Weather conditions for Inauguration Day

[Ed Mahmoud]

Euro shows nice storm winding down for DC by Monday evening, then breezy and cold for Inauguration Day.

Sunday evening, storm near DC, likely with snow.


Monday night, storm in Eastern New England, which should mean it is about over in DC, but high 850 and 700 mb level RH's imply clouds, maybe snow showers.


Tuesday evening- breezy and cool, but a wind shifting to West should provide some downslope warming, and the core of the cold is starting to pass DC by.

[cycloneye]

D.C. NWS discounts the EURO.

THE BEST CHANCE FOR AT LEAST LOW CHANCE SNOW PROBABILITIES LOOKS
TO BE SUNDAY AS THE LOW WASHES OUT AND THE INCOMING DYNAMICS OF
THE UPPER TROF PUSH THE DISSIPATING FRONT ACROSS THE REGION. THE
00Z EUROPEAN DOESN/T DISSIPATE THE LOW AND INSTEAD DEVELOPS A
NOR`EASTER FOR THE NEW ENGLAND STATES SUNDAY INTO EARLY MON...AN
UNLIKELY SCENARIO AT THIS TIME.

http://forecast.weather.gov/product.php ... hlight=off

[cycloneye]

12z GFS at 144 hours shows dry but cold weather on the 20th.No Nor-Easter as EURO has.There is a low but is well east of the coast.

[Ed Mahmoud]

Just checked on Joe Bastardi. 10 am update, he prefers Euro look for a pre-inaugural snowstorm, discounts GFS.


Not that he is certain to be right...

[cycloneye]

12z EURO at 144 hours shows dry but cold 20th in D.C,no Nor-Easter around.

http://www.ecmwf.int/products/forecasts ... 9011412!!/

[Ed Mahmoud]

12z EURO at 144 hours shows dry but cold 20th in D.C,no Nor-Easter around.

http://www.ecmwf.int/products/forecasts ... 9011412!!/

No way to guess the amounts, and it is over by Tuesday, but looks like a good shot of snow on Monday. Which'll make DC look all nice and sparkly.

[cycloneye]

Weather Channel Latest Forecast for January 20th in D.C.

4:31 pm ET
Inauguration Day weather: The inauguration of President-elect Obama is 6 days away and millions will arrive in Washington, D.C. to be witnesses of this historic day.


We've been following the forecast for a few days now and nothing notable has changed from yesterday to today.

The main concern remains the question of how much cold air will be in place and how strong will the winds be.

No, the temperature won't be as cold as this coming Friday when weather.com predicts a high of just 20 degrees. But on the other hand, it won't be very warm either. Reinforcing cold shots from the North will keep high temps in the mid 30s.

Meanwhile, there's the wind factor we'll have to contend with. If you believe the computer weather models right now, there is possibility for a modest storm to take shape somewhere off the East coast.

It's not the snow we're worried about but the tight pressure gradient that develops between the low pressure and the high pressure building in the central U.S. This setup aids in the creation of strong northerly winds blowing through Washington D.C.

So you probably know where we're going with this; the wind chill factor may become a big player on Tuesday. Temps in the 30s and winds out of the north at 15 to 30 mph equals wind chills in the upper teens to mid 20s. Just something to keep in mind as we fine-tune the forecast leading up to January 20.

http://www.weather.com/newscenter/topst ... auguration

[cycloneye]

12z GFS at 120 hours shows dry but still below average temps for the 20th.Maybe some brief flurries on Monday.



http://www.nco.ncep.noaa.gov/pmb/nwprod ... el_l.shtml

[cycloneye]

The latest D.C. forecast:


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
300 PM EST THU JAN 15 2009

LONG TERM /SATURDAY THROUGH THURSDAY/...

THE UPPER HIGH PRESSURE RIDGE ACROSS THE WRN HALF OF NA CONTINUES TO
AMPLIFY AND PUSH EAST SATURDAY AND SUNDAY...EXTENDING INTO THE NW
TERRITORIES. IN RESPONSE TO THIS RIDGE...THE UPPER TROF OVER THE ERN
HALF OF NORTH AMERICA DIGS DOWN TO THE GULF COAST BY SUNDAY NIGHT.
THE STRONG LOW LEVEL HIGH PRESSURE PUSHES OFF THE MID ATLANTIC COAST
LATER SATURDAY WHILE AN OPEN WAVE LOW DEVELOPS AND SPILLS INTO THE
SOUTHERN GREAT LAKES SATURDAY NIGHT. LATEST GFS/EURO BOTH
SLOWER...TAKING THE SFC LOW ASSOCIATED WITH THIS WAVE FROM LAKE ERIE
SUNDAY MORNING TO UPSTATE NEW YORK THROUGH SUNDAY NIGHT. THE COLD
FRONT EXTENDING FROM THIS LOW CROSSES THE ERN MID ATLANTIC SUNDAY
EVENING/NIGHT. THIS SYSTEM...WITH SUBSEQUENT DISTURBANCES...BRINGS
SEVERAL DAYS OF UPSLOPE SNOW TO THE WESTERN SIDES OF THE ALLEGHENY
FRONT STARTING SATURDAY EVENING. MOISTURE FROM THE GULF BEGINS TO BE
AVAILABLE TO THIS SYSTEM STARTING LATE SATURDAY AS THE HIGH PUSHES
OFF THE COAST. DELAYED SLIGHT CHANCE FOR SNOW BEYOND (EAST) OF
UPSLOPE AREAS UNTIL LATE SATURDAY NIGHT WITH CHANCE POPS FOR SUNDAY
AFTERNOON AND EVENING.

THE UPPER WAVE PATTERN CONTINUES TO SHIFT EAST THRU MID WEEK...SO
THAT BY TUESDAY ANY SFC LOW FORMING UNDER THE EASTERN PORTION OF THE
TROUGH WOULD BE WELL OFF THE MID-ATLANTIC COAST. HOWEVER...A FEW
SHORTWAVES/ AREAS OF VORTICITY WILL PUSH THE UPPER TROF INTO THE MID
ATLANTIC MONDAY THRU TUESDAY NIGHT. THIS UPPER TROUGH WILL BE CUTOFF
FROM BOTH THE GULF AND GULF STREAM (MAIN MOISTURE SOURCES)...AND
THESE SHORTWAVES WILL REINFORCE THE COLD AIR...SO ONLY LIGHT SNOW
SHOWERS/FLURRIES ARE EXPECTED WITH EACH PASSAGE MIDDAY MONDAY
THROUGH TUESDAY NIGHT. IN ADDITION...THE TRACK OF THE SHORTWAVES
BRINGS THEM ACROSS THE APPALACHIANS SO ANY MOISTURE WILL BE SQUEEZED
BEFORE SPILLING ONTO THE EASTERN SEABOARD. THE TIMING OF THE
SHORTWAVES MONDAY THROUGH TUESDAY NIGHT IS VERY UNCERTAIN...WENT
WITH SLIGHT CHANCE OF LIGHT SNOW THROUGH THIS PERIOD...CHANCE FOR
UPSLOPE PORTIONS OF EXTREME WESTERN FORECAST AREA. TEMPERATURES LOOK
TO BE FIVE TO TEN DEGREES BELOW NORMAL ACROSS THE AREA SUNDAY THRU
WEDNESDAY WITH HIGHS IN THE LWR TO MID 30S...LOWS IN THE LWR TO MID
20S.

http://forecast.weather.gov/product.php ... hlight=off

[cycloneye]

The latest NWS forecast.

.LONG TERM /SATURDAY THROUGH THURSDAY/...

ANOTHER SWIFT UPPER VORT WILL BARREL TOWARD THE AREA FROM THE
UPPER MIDWEST...BUT AS THE BACKSIDE TROF DEEPENS INTO THE MID/LOWER
MISSISSIPPI VLY LATE SAT INTO EARLY SUNDAY...THE SFC LOW SLOWS IT/S
MOMENTUM OVER THE SRN GRT LKS WHILE THE UPPER TROF DIGS DOWN INTO
THE SRN APLCNS. A COLD FRONT ASSOCIATED W/ THE GREAT LAKES LOW
INITIALLY SLIDES INTO THE CNTRL APLCNS EARLY SUNDAY. THEN...A WEAK
LEE SFC LOW DEVELOPS ACROSS THE BY LATE MRNG/EARLY AFTN AND SLIDES
EWD ACROSS THE MID ATLC THRU THE LATE AFTN HRS. SURROUNDING ALL OF
THIS ACTIVITY WILL LIKELY BE SCATTERED SNOW BANDS STREAMING ACROSS
THE REGION...THE BEST CHANCES ACROSS THE HIGHER UPSLOPE AREAS OF
THE CNTRL APLCNS AND ALONG THE PA/MD BORDER.

AS THE LOW TROF DEVELOPS AND FRONTOGENESIS STRENGTHENS E OF THE BLUE
RIDGE...LIGHT SLY WINDS WILL LIKELY CONTRIBUTE TO LOCALIZED SNOW
BAND DEVELOPMENT CLOSER TO THE BAY...BUT LIKELY INCLUDING THE I-95
CORRIDOR AT LEAST FOR A TIME DURING THE AFTN HRS. MODELS FAIRLY
SPLIT ON EITHER DRAGGING A DRY COLD FRONT OR NEARLY SATURATING THE
REGION W/ AT LEAST SCATTERED PRECIP. TEMPS SHOULD PEAK JUST ABOVE
FREEZING ACROSS THE PIEDMONT AND COASTAL REGIONS OF THE MID
ATLC...THO STILL LOW DWPTS AND THE WAA REGIME WELL OFFSHORE...
FALLING PRECIP SHOULD FALL AS SNOW XCPT FOR LWR SRN MD WHERE RASH
PSBL. SINCE THE DYNAMICS OF THIS INCOMING SYSTEM ARE WEAK AND THE
MOISTURE RETURN INTO THE MID ATLC WILL ALSO BE MINIMAL...AMOUNTS/QPFS
WILL ALSO BE LIGHT.

DURING THE AFTN HRS ON SUNDAY...THE NAM HAS THE MID ATLC IN THE
LEFT ENTRANCE REGION OF A MODERATELY STRONG UPPER JET...AN
UNFAVORABLE REGION FOR LONG LIVED AREAS OF LIFT...W/ MUCH OF THE
MORE INTENSE OMEGA WELL OFFSHORE. THEN MODELS DEVELOP A SHORT
PERIOD OVERNIGHT SUN INTO EARLY MONDAY...OF A TRIFECTA OF LOWS
STREWN ACROSS THE NORTHEAST. THE TWO NORTHERN LOWS QUICKLY
DISSIPATE AHEAD OF THE DEEPENING MID ATLC COASTAL LOW...AIDED BY
THE INCREASING AFOREMENTIONED UPPER DYNAMICS. THIS ACTIVITY SLIDES
QUICKLY NEWD ACROSS THE NORTHEAST COAST /CAPE COD/ EARLY MONDAY
AND THRU MIDDAY. THE EFFECTS ON THE MID ATLC WILL BE BREEZY
CONDITIONS FROM THE LEFTOVER SFC PRES GRADIENT AS THE NORTHEAST
INTENSIFIES OVER SRN MAINE/NOVA SCOTIA.

TUESDAY /STILL HINGING ON ALL THIS PREVIOUS ACTIVITY/ LOOKS A BIT
MORE QUIESCENT AS A DEEP AND COLD BUT LESS OMINOUS UPPER TROF
GRADUALLY PUSHES OVER THE ERN SEABOARD. STILL KEEPING THE OUTSIDE
CHANCE OF A FEW ISOLATED NW-FLOW SNOW BANDS AND MCLOUDY/PARTLY
SUNNY SKIES FOR AT LEAST THE MRNG HRS...POSSIBLY DECREASING DURING
THE AFTN AS A PORTION OF THE UPPER VORT MAX SLIDES OVER THE REGION.
THE BIGGER HEIGHT STRATIFICATION FROM THE UPPER TROF OCCURS OVER
THE DEEP SOUTH...WHERE ANOTHER OFFSHORE SFC LOW IS EXPECTED TO
DEVELOP OFF THE SOUTHEAST COAST BY LATE TUE. THE 00Z ECMWF DEVELOPS
A STRONG SFC LOW A COUPLE HUNDRED MILES OFF CAPE HATTERAS TUES
NIGHT. A WEAK UPPER SHRTWV THEN SLIDES DOWN THE BACKSIDE OF THE
SLOWLY EXITING UPPER TROF OVER ERN CANADA...MUCH OF THE PRECIP
SLIDING INTO THE UPSLOPE AREAS OF THE CNTRL APLCNS.

[srainhoutx]

After reading the morning HPC Update and looking through some 00Z and new 12Z GFS guidance. Could we see a 1961 repeat in the making? Time will tell, but it "could" make for some interesting snow removal from the day prior. We shall see.

[cycloneye]

From Accuweather



http://www.accuweather.com/regional-new ... eastusnews

[Ed Mahmoud]

European has been on this several days, the day before snowfall.

GFS now aboard, 3 or 4 inches of snow (which I think is a good storm by DC standards) on Monday followed by mid 20sF on Tuesday.

[Jason Foster]

First,off the bat,this thread is only to discuss all the aspects of how the weather will be on January 20th,when the swearing-in ceremony of the 44th President of the United States will take place and not discuss anything else apart from the weather.The thread will also have historical information about past Inauguration days in terms of weather.

Sounds like you didn't want this to go down the road of another thread on a separate forum...can't say I blame you.

Anyway. I think right now, it is clear that it will be cold. With all the info out there right now...looks like between 28° to 40°. That seems to be the range of error of most sources (models, personal forecasters, etc.). "If" any show falls (and I say with great hesitation), it looks like more of the public (aka TV) forecasters aren't biting yet. All I hear from them is flurries or dusting. I tend to go that route just from personal experience. Seems all season the models have put more moisture into our area than has actually fallen. So we'll see.

Of course for me, I'd love to see snow on that day...give me more to do when I'm down there photographing the event.

[srainhoutx]

HPC Final Updated has backed away from anything significant along the E Coast Monday through Wednesday for now based on the 12Z ECMWF...snipet...

ACCORDINGLY...DECIDED TO LET FINAL HPC GUIDANCE MAINTAIN MOST
CONTINUITY FOR MOST OF THE NATION DAYS 3-7 AS INITIALLY DERIVED
FROM THE 00 UTC ECMWF...ALBEIT WITH A HEALTHY DOSE OF ECMWF
ENSEMBLE MEAN OVER TIME TO ADDRESS UNCERTAINTY. HOWEVER...AMID
INCREASED SHORT RANGE LEAD-IN UNCERTAINTY FROM 12 UTC
GUIDANCE...THE FINAL HPC PROGS HAVE BACKED SLIGHTLY AWAY FROM 00
UTC ECMWF LOW DEVELOPMENTS OVER THE E-CENTRAL THEN UP THE E COAST
US MON-WED.

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

[cycloneye]

NWS in D.C. is somewhat in the uncertain side deciding between the EURO and GFS,which one will be right.

LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --MODELS ARE IN GOOD AGREEMENT THROUGH 12Z SUNDAY...PLACING SURFACE
LOW PRESSURE ACROSS THE GREAT LAKES. AHEAD OF LOW PRESSURE...MODELS
AND SREFS INDICATE LOW CHANCES OF MEASURABLE PRECIPITATION...WHICH
WOULD BE IN THE FORM OF SNOW...ACROSS FAR NORTH AND WEST PORTIONS OF
OUR CWA SATURDAY NIGHT INTO SUNDAY MORNING. BACKED OFF ON CHANCES
ACROSS THE REMAINDER OF THE CWA THROUGH SUNDAY MORNING. A FRONT
ATTACHED TO LOW PRESSURE WILL MOVE THROUGH THE CWA SATURDAY
AFTERNOON. THIS FRONT WILL BRING A CHANCE OF SNOW ACROSS THE ENTIRE
CWA...WHICH COULD BE MIXED WITH RAIN SOUTH OF WASHINGTON PER 09Z
SREFS.

WHAT HAPPENS BEYOND SATURDAY AFTERNOON IS MUCH MORE INTERESTING AND
CHALLENGING. 12Z GFS DEVELOPS LOW PRESSURE ACROSS THE SOUTHEAST
STATES ON SUNDAY AND TREKS IT NORTHEAST ALONG THE MID ATLANTIC COAST
THROUGH MONDAY MORNING AND UP THE NORTHEAST COAST MONDAY AFTERNOON.
THIS SOLUTION WOULD BRING INCREASED CHANCES OF SNOW ACROSS THE CWA
ESPECIALLY AREAS EAST OF THE BLUE RIDGE SUNDAY NIGHT INTO MONDAY
MORNING. THERE/S SOME SUPPORT FROM THE 09Z SREF AND GFS ENSEMBLES IN
THIS SOLUTION. HOWEVER...THE 00Z AND 12Z ECMWF DOES NOT SUPPORT THIS
SOLUTION AND HAS LITTLE OR NO PRECIPITATION CHANCES SUNDAY NIGHT
INTO MONDAY MORNING EXCEPT FOR UPSLOPE AREAS OF THE HIGHLANDS. THE
12Z NAM IS IN THE SAME CAMP AS THE ECMWF. THE DIVERGING SOLUTIONS
ADD TO THE UNCERTAINTY OF THIS FORECAST. AFTER MUCH CONSIDERATION
AND COLLABORATION...WE HAVE DECIDED TO INCREASE CHANCES OF SNOW
ACROSS THE CWA IN LIGHT OF THE GFS/GFS ENSEMBLE/SREF FORECASTS. IF
THEY ARE CORRECT...SOME SNOW ACCUMULATION IS LIKELY. ON THE FLIP
SIDE...IF THE ECMWF/NAM SOLUTIONS WIN OUT...THEN LITTLE OR NO SNOW
MAY OCCUR. WE WILL NEED TO KEEP A CLOSE WATCH ON THIS SYSTEM AND
ADJUST DETAILS AS MODEL GUIDANCE BECOMES IN BETTER AGREEMENT.

IN ADDITION...THE FATE OF THE SUNDAY NIGHT/MONDAY SYSTEM WILL HELP
TO DETERMINE WHAT HAPPENS EARLY IN THE WEEK. CONTINUE TO LIKE THE
THEME OF AN UPPER TROUGH ACROSS THE MID ATLANTIC WITH SMALL VORT
FEATURES POSSIBLY ROTATING THROUGH. BECAUSE OF THIS...HAVE CONTINUED
TO HAVE PLENTY OF CLOUDS ALONG WITH A SLIGHT CHANCE OF SNOW SHOWERS
ON TUESDAY. AT THIS TIME...ANY COASTAL DEVELOPMENT ON TUESDAY LOOKS
TO BE WELL SOUTHEAST OF THE LOCAL AREA...BUT WILL OBVIOUSLY NEED TO
BE MONITORED ESPECIALLY IF THE SUNDAY NIGHT/MONDAY SYSTEM IS NOT AS
AGGRESSIVE AS THE GFS INDICATES.

http://forecast.weather.gov/product.php ... hlight=off

[cycloneye]

NWS in D.C. latest forecast still has uncertainty this close to Inauguration day as they are divided in two camps about which modekls will get it right.


.LONG TERM /SUNDAY THROUGH SATURDAY/...

LOOKED AT MANY ENSEMBLES AND A FEW DETERMINISTIC MODELS TONIGHT
THE 00Z CANADIAN ENSBL...21Z SREF...12Z EURO...00Z GFS...12Z GFS
ENSBL...AND 00Z NAM. THE GFS PHYSICS SEEM TO PRODUCE THE BEST CHC OF
PRECIP FOR OUR FORECAST AREA.

THE EURO AND CANADIAN SEEM TO KEEP THE BULK OF THE PRECIP WITH THE
CLIPPER TO OUR N. THEY BRING SOME SNOW INTO THE MTNS AND SOME
FLURRIES OR SCT SNOW SHWERS FOR THE REST. THEN ANY COASTAL
DEVELOPMENT STAYING SE OF OUR AREA...WHICH FALLS IN WELL WITH THE
UPPER PATTERN AND THE 500MB RIDGE OVER THE ROCKIES. WITH THE
CORRESPONDING TROF TOO FAR EAST...THAT SHOULD TEND TO KEEP ANY
COASTAL DEVELOPMENT WELL SE OF DC. THE 00Z NAM IS SIMILAR...AND
GIVES ONLY A FEW FLURRIES FOR MUCH OF THE FORECAST AREA.

THE 21Z SREF HAS A SIMILAR NOTION AS THE ABOVE EURO AND CANADIAN...
BUT IT BRINGS THE COASTAL DEVELOPMENT CLOSER AND SPREADS AT LEAST A
FEW HUNDEREDTHS OF AN INCH OF PRECIP TO DC. THE OMINOUS THING ABOUT
THE SREF IS THAT EACH MODEL RUN HAS BEEN COMING IN EVEN FURTHER TO
THE NW WITH THE PRECIP SHIELD...RATHER THAN PUSHING OFFSHORE AND
CLOSER TO THE EURO AND CANADIAN ESMBLS. ANOTHER CAVEAT WITH THAT IS
THAT THE RAIN SNOW LINE HAS ALSO BEEN PUSHING CLOSER AND CLOSER TO
DC WITH EACH RUN.

THE 12Z GSF ENSBLS ARE SIMILAR TO THE 21Z SREF BUT BRING MORE PRECIP
WITH THE COASTAL DEVELOPMENT...WITH AMOUNTS AROUND TWO TENTHS OF AN
INCH. WHILE THE LATEST GFS OPERATIONAL RUN IS SIMILAR TO ALL THAT
BUT WITH ONLY EIGHT HUNDEREDTHS OF QPF.

SO WHERE DOES THAT LEAVE US? THERE ARE TWO CAMPS WITH ALL THIS. THE
ENSEMBLES AND MODELS THAT RELY ON GFS PHYSICS...WHICH GIVE SOME
LIGHT SNOW...POSSIBLY MIXED WITH RAIN IN LOWER S MD. BEST CHANCE FOR
PRECIP AT THIS TIME WITH THESE SEEM TO BE 9PM SUN THRU 4AM MON. AND
THEN THERE ARE ALL THE OTHER MODELS. THESE ALL SEEM TO INDICATE
LITTLE TO NO PRECIP FOR THE FORECAST AREA...EXCEPT THE MTNS. THE
DISTURBING THING TO ME IS THAT THE GFS SEEMS TO BE DOUBLING DOWN AND
INCREASING THE EXTENT OF PRECIP OVER THE AREA WITH EACH RUN...RATHER
THAN DOING THE OPPOSITE AND COMING AROUND TO THE OTHERS. AS ALWAYS
TIME WILL TELL. FOR THE SUN NIGHT POP FORECAST FOR NOW...WILL START
WITH THE GFS MOS FOR A WORST CASE AND ADJ THAT DOWN A LITTLE.

ANOTHER ISSUE...THE MOS TMPS FOR SUN SEEM TO BE TOO HIGH. HARD TO
IMAGINE TEMPS RISING 20 TO 25 DEGS WITH LIGHT WINDS AND OVERCAST
SKIES. MODELS WERE TOO WARM WITH YESTERDAYS HIGHS...LOOKS LIKE THAT
CONTINUES TODAY AND SUNDAY. COOLING THE OPTIMISTIC MODELS WOULD ALSO
PUSH THE RAIN SNOW LINE FURTHER SE THAN THEY INDICATE CURRNTLY.

FOR MONDAY WILL MAITAIN SOME POPS FOR NOW...MOSTLY IN THE MORNING.
MONDAY NIGHT LOOKS DRY. WILL HOLD ONTO SLT CHC ON INAUG DAY TUE. THE
UNCERTAINTY FOR SUN/MON WILL PLAY A ROLE IN THE SYNOP SITUATION WE
WILL FIND OURSELVES IN ON TUE.

http://forecast.weather.gov/product.php ... hlight=off

[cycloneye]

The uncertainty is now over and now NWS of D.C. calls for a trace or no snow for the Capital as the coastal low will be far away from the coast.

LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...

MODELS HAVE COME INTO BETTER AGREEMENT REGARDING THE SUNDAY
NIGHT/MONDAY TIME PERIOD. 06Z AND 12Z GFS HAVE BACKED OFF ON COASTAL
LOW PRESSURE AFFECTING THE MID ATLANTIC SUNDAY NIGHT INTO EARLY
MONDAY. 03Z AND 09Z SREFS DID THE SAME...WHICH CONVERGES TOWARD
ECMWF AND NAM SOLUTIONS. THIS HAS LEAD TO AN INCREASE IN CERTAINTY
AND CONFIDENCE FOR OUR FORECAST.

A MORE NORTHERN STREAM SHORTWAVE/CLIPPER SYSTEM IS STILL POISED TO
MOVE ACROSS THE AREA SUNDAY NIGHT. THIS SYSTEM WILL PRODUCE SNOW
MAINLY WEST OF THE MTNS...BUT THERE IS A CHANCE THAT A LITTLE BIT OF
LIGHT SNOW WILL BE ABLE TO MAKE IT EAST OF THE MTNS INCLUDING THE
BALTIMORE/WASHINGTON METRO AREA. WITH THE COASTAL SYSTEM NOT
EXPECTED TO AFFECT THE AREA NOW...AND ANY SNOW BEING A FUNCTION OF
THE WEAK CLIPPER SYSTEM...WE HAVE LOWERED OUR CHANCES OF SNOW INTO
THE CHANCE CATEGORY. PRECIPITATION COULD EVEN BEGIN OR MIX WITH RAIN
SOUTHEAST OF WASHINGTON IN THE EVENING. ACCUMULATIONS MAY BE AN INCH
OR TWO ACROSS THE HIGHLANDS...BUT ANY ACCUMULATIONS EAST OF THE MTNS
WOULD MORE THAN LIKELY ONLY BE A TRACE TO A COATING.

THIS LIGHT SNOW WOULD BE DONE BY SUNRISE MONDAY...WITH ANY LEFTOVER
SNOW GENERALLY OCCURRING FROM AN UPSLOPE COMPONENT ACROSS THE
HIGHLANDS. AN UPPER TROUGH WILL REMAIN OVER THE MID ATLANTIC MONDAY
AND TUESDAY. THIS WILL KEEP PLENTY OF CLOUDS AROUND...BUT CHANCES OF
SNOW EAST OF THE MTNS LOOKS SLIM TO NONE. THEREFORE...HAVE REMOVED
MENTION OF SNOW SHOWERS EAST OF THE MTNS ON TUESDAY. WITH NORTHWEST
FLOW...TEMPERATURES WILL BE BELOW CLIMO AND OCCASIONAL UPSLOPE SNOW
WILL OCCUR OVER THE HIGHLANDS.

http://forecast.weather.gov/product.php ... hlight=off

[cycloneye]

Some flurries late today for D.C.,but for Inauguration day,it will be cold but sunny.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
320 AM EST SUN JAN 18 2009

.SYNOPSIS...
-- Changed Discussion --AN AREA OF LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES TODAY INTO
TONIGHT. THE COLD FRONT ASSOCIATED WITH THIS LOW WILL PASS THROUGH
THE MID-ATLANTIC LATER TODAY AND TONIGHT. A MID-LEVEL TROUGH OF LOW
PRESSURE WILL REMAIN IN PLACE THROUGH TUESDAY BRINGING CHILLY
CONDITIONS. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE
OF THE WEEK.-- End Changed Discussion --


&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --CURRENT ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER THE
GREAT LAKES AND THE COLD FRONT ASSOCIATED WITH THIS LOW MOVING
THROUGH THE OHIO VALLEY. A MID-LEVEL TROUGH OF LOW PRESSURE REMAINS
OVER THE EASTERN PORTION OF THE NATION.

THE LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL SLOWLY DRIFT EAST
AND THE COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE INTO THE AREA
THIS AFTERNOON. CURRENT RADAR SHOWS MOST OF THE PRECIPITATION OFF TO
OUR NORTH THIS MORNING AND THAT SHOULD CONTINUE TO BE THE CASE
THROUGHOUT THE DAY. THE BEST LIFT REMAINS TO OUR NORTH CLOSER TO THE
LOW. AS THE COLD FRONT MOVES INTO THE REGION THIS AFTERNOON ANOTHER
UPPER-LEVEL DISTURBANCE ROTATING AROUND THE TROUGH WILL CAUSE A
SURFACE LOW TO DEVELOP ALONG THE FRONT. HOWEVER...WITH THE TROUGH
AXIS REMAINING POSITIVELY TILTED AND FAST WINDS ASSOCIATED WITH THE
SOUTHERN STREAM OF THE JET...THIS AREA OF LOW PRESSURE WILL HAVE
LITTLE INFLUENCE ON OUR WEATHER. NAM/GFS BUFKIT DO SHOW LIMITED
INSTABILITY DEVELOPING AHEAD OF THE FRONT AND WE DO REMAIN IN THE
FAVORABLE REGION OF A MID-LEVEL JET MAX MOVING THROUGH.
THEREFORE...WILL CONTINUE WITH SLIGHT CHANCE TO CHANCE POPS CLOSER
TO THE FRONT THIS AFTERNOON MAINLY ACROSS LOCATIONS WEST OF THE BLUE
RIDGE. HAVE ADDED THE CHANCE FOR FLURRIES THIS AFTERNOON FOR
BALTIMORE AND WASHINGTON DC...BUT THE BEST CHANCE FOR PRECIPITATION
SHOULD HOLD OFF UNTIL THIS EVENING.

ALONG AND WEST OF THE ALLEGHENY FRONT...PLENTY OF LOW-LEVEL MOISTURE
AND A SLIGHT UPSLOPE COMPONENT TO THE LOW-LEVEL FLOW WILL ALLOW FOR
SNOW SHOWERS TODAY. NAM/GFS BUFKIT ALSO INDICATE SOME INSTABILITY
AHEAD OF THE FRONTAL PASSAGE...BUT THE INVERSION REMAINS RATHER
SHALLOW AND WITH A SOUTHWEST FLOW THE UPSLOPE COMPONENT TO THE
LOW-LEVEL FLOW WILL BE WEAK. SO DID NOT ISSUE AND ADVISORY. SNOW
ACCUMULATIONS GENERALLY LESS THAN ONE INCH ARE EXPECTED THROUGH THIS
AFTERNOON.

WITH A SOUTHERLY FLOW AHEAD OF THE FRONT...MAX TEMPS WILL BE
NOTICEABLY MILDER COMPARED TO RECENT DAYS DESPITE THE CLOUD COVER.
MAX TEMPS WILL RANGE FROM THE UPPER 20S IN PORTIONS OF THE POTOMAC
HIGHLANDS TO AROUND 40 IN WASHINGTON DC.-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
-- Changed Discussion --THE COLD FRONT WILL CONTINUE TO PASS THROUGH THE REST OF THE CWA
THIS EVENING. WITH SOME INSTABILITY AHEAD OF THE FRONT AND A JET
MAX MOVING THROUGH...WILL CONTINUE WITH SLIGHT CHANCE TO CHANCE POPS
FOR SNOW SHOWERS THIS EVENING FURTHER EAST ACROSS THE METROPOLITAN
AREAS. THIS IS ABOVE WHAT THE LATEST GUIDANCE IS SUGGESTING. SNOW
ACCUMULATION...IF ANY WOULD BE LIGHT AND CONFINED MAINLY TOWARDS
NORTHERN MARYLAND.

THE MID-LEVEL TROUGH OF LOW PRESSURE WILL REMAIN OVER THE REGION
BEHIND THE FRONT OVERNIGHT. LEFT THE SLIGHT CHANCE FOR SNOW SHOWERS
IN THE FORECAST ACROSS THE METROPOLITAN AREAS...BUT NO ACCUMULATION
IS EXPECTED. FURTHER WEST ALONG THE ALLEGHENY FRONT...A PERIOD OF
UPSLOPE SNOW WILL BRING ADDITIONAL SNOW ACCUMULATIONS. A WINTER
WEATHER ADVISORY MAY BE WARRANTED DURING THIS TIME...BUT DID NOT
ISSUE IT WITH THIS PACKAGE. THE INVERSION WILL REMAIN SHALLOW
DESPITE COLDER AIR AND A BETTER UPSLOPE COMPONENT TO THE LOW-LEVEL
FLOW. WILL GO WITH ADDITIONAL ACCUMULATIONS AROUND AN INCH FOR
NOW.-- End Changed Discussion --

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
-- Changed Discussion --A COMPLEX UPPER TROUGH PATTERN REMAINS OVER THE AREA THRU THE EARLY
PART OF THE WEEK. THE CENTER OF THE UPPER WAVE MOVES ACROSS THE
EASTERN GREAT LAKES SUNDAY NIGHT THRU MONDAY NIGHT. THE TROUGH
EXTENDING FROM THIS SYSTEM WILL CROSS THE MID-ATLANTIC SUNDAY
NIGHT...THEN DEVELOPS INTO A COASTAL LOW THAT RACES UP THE NE COAST
ON MONDAY. WENT WITH CHC POP FOR SNOW WRN MTNS. SCHC FOR LIGHT SNOW
SHOWERS ON MONDAY EAST OF THE MOUNTAINS...INCLUDING THE
BALTIMORE/WASHINGTON METRO AREA...WHERE SOME LIMITED MOISTURE EXISTS
WITH POSSIBLE INSTABILITY PER NAM/GFS BUFR SOUNDINGS.

GFS/EURO BOTH DEVELOP A COASTAL LOW OFF HATTERAS ON
TUESDAY...WITH MID LEVEL TROUGH AXIS ALONG THE EASTERN
SEABOARD...THE TRACK IS WELL OUT TO SEA WITH ANY ASSOCIATED PRECIP
HELD OFF MID-ATLANTIC COAST TUESDAY AND WEDNESDAY. THEREFORE TUESDAY
APPEARS DRY...EXCEPT FOR UPSLOPE PARTS OF THE MOUNTAINS WITH NW FLOW
ACROSS THE MID-ATLANTIC. TEMPERATURES FIVE TO TEN DEGREES BELOW
NORMAL EARLY AND MID WEEK WITH TUESDAY BEING THE COLDEST DAY.

LATE WEEK...EURO SOLUTION DEVELOPS MORE ZONAL FLOW ON WEDNESDAY WITH
ANY CYCLOGENESIS NORTH OF THE MID-ATLANTIC IN THE LATE PART OF THE
WEEK. THE GFS AMPLIFIES THE FLOW ENOUGH TO BRING A LOW ACROSS THE
SOUTHERN GREAT LAKES WITH FROPA ACROSS THE MID-ATLANTIC FRIDAY
NIGHT. MAINTAINED SLIGHT CHANCE POPS ON FRIDAY AND FRIDAY NIGHT
GIVEN UNCERTAINTY. TEMPERATURES MODERATE TO NEAR OR EVEN SLIGHTLY
ABOVE NORMAL FOR THURSDAY/FRIDAY.-- End Changed Discussion --

[cycloneye]

Some flurries are falling today in D.C.but it will be sunny and cold for tommorow.

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
601 AM EST MON JAN 19 2009

.SYNOPSIS...
UPPER DISTURBANCES WILL ROTATE AROUND A MEAN UPPER TROUGH OVER THE
NORTHEASTERN STATES TODAY...BRINGING A CHANCE OF LIGHT SNOW FOR
MUCH OF THE AREA. AN UPPER LEVEL TROUGH WILL REMAIN IN PLACE ON
TUESDAY. A COASTAL LOW DEVELOPS ALONG THE CAROLINA COAST TUESDAY
AND PUSHES OUT TO SEA BY WEDNESDAY. HIGH PRESSURE GRADUALLY BUILDS
IN TOWARD THE END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --WITH BROAD SHIELD OF PCPN SPREADING NEWD WITH APRCH OF SHRTWV
TROF...HAVE EXTENDED WINTER WX ADZY FOR NRN THREE ZONES ALONG NRN
PORTION OF ALLEGHENY FRONT. UPSLP FLOW AND LIFT SHUD INCR THIS
AREA AS TROF APRCHS...AND THESE SHUD ENHANCE SNOW GENERATION THIS
MRNG. WILL CONT ADZY TO 17Z. PRVS DSCN FOLLOWS...

MEAN TROF LOCATED OVER NERN CONUS THIS MRNG. SVRL SHRTWV TROFS
MOVG AROUND THE LARGER TROF. ONE SUCH SHRTWV TROF SPARKED LGT SHSN
ACRS NRN MD...ERN WV PNHDL AND EXTREME NRN VA DURG LATE NGT HRS.
THESE SNSH WERE DECRG IN CVRG THIS MRNG.

SFC CDFNT HAVING DIFFICULT TIME MAKING EWD PROGRESS OUT OF WRN
POTOMAC HIGHLANDS. THIS LKLY IS A RESULT OF SECOND SHRTWV TROF
APRCHG OVER CNTRL WV ATTM...AND YIELDING SLGTLY MORE AGGRESSIVE
SHIELD OF PCPN. THIS SECOND TROF WILL MOVE THRU FCST AREA TDA...
AND CDFNT XPCD TO MOVE THRU IN KIND.

PCPN XPCD TO INCR ACRS WRN HIGHLAND AND PENDLETON CNTYS THIS MRNG
AS LIFT SPREADS EWD AND UPSLP FLOW INCRS. HAVE EXTENDED WINTER WX
ADZY THRU TDA...MAINLY FOR WRN SLOPES. LESS CERTAINTY IN TYPICAL
UPSLP AREAS FURTHER N...AND SO WILL RUN WINTER WX ADZY THRU 6 AM
FOR NRN ZONES.

SNOW XPCD TO SPREAD OVER MUCH OF FCST AREA THIS MRNG AND SPCLY
THIS AFTN AS WAVE MOVES THRU. TOTALS GENLY AROUND ONE HALF INCH
XPCD. HOWEVER...MODELS DVLP SMALL AMTS OF INSTBY THIS AFTN OVER
ERN ZONES...VCTY CHSPK BAY AND POTOMAC. NEAR DC AND BALTIMORE
METRO AREAS...MAY SEE ACCUMULATIONS SLGTLY HIGHER THAN ONE HALF
INCH...DURG AFTN COMMUTE. CONFIDENCE IN SNOW IS HIGH...BUT STILL
SOME UNCERTAINTY ON QPF. IF CNVCTV SNOW TREND DVLPS THIS AFTN...
LKLY WILL NEED WINTER WX ADZY FOR PORTIONS OF METRO COMMUTING
AREAS. SHUD BCM MORE CLR BY MRNG UPDATE.

GUIDANCE MAXIMA SEEMED A BIT HIGH GIVEN XPCD CLD CVR...SO HAVE
UNDERCUT MEXMOS SLGTLY TDA. MAY SEE UPWD TREND IN TEMPS ACRS SRN
ZONES LATE THIS AFTN AS CLD CVR ERODES IN WAKE OF SHRTWV TROF.-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
SHRTWV TROF EXITS RAPIDLY THIS EVE. MAINTAINED CHC POPS ERN ZONES
EARLY EVE FOR LINGERING PCPN...BUT ALL PCPN SHUD EXIT BY MID EVE...
WITH THE XCPTN OF UPSLP FAVORED AREAS.

COOL MINIMA TNGT...SPCLY IN WRN ZONES OWING TO SNOW CVR. GENLY UPR
TEENS TO LWR 20S...XCPT WRN ZONES...WHERE MINIMA MAY REACH 10-15
DEG F.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE UPPER TROUGH PATTERN OF THE PAST WEEK PERSISTS OVER THE AREA FOR
INAUGURATION DAY BEFORE BEGINNING TO BREAK DOWN INTO MORE ZONAL FLOW
ON WEDNESDAY. AN OUTCOME OF THIS TRANSITION IS THE DEVELOPMENT OF A
COASTAL LOW OFF THE CAROLINA COAST ON TUESDAY. THE TRACK OF THIS
SYSTEM IS NE ALONG THE GULF STREAM /AWAY FROM THE MID-ATLANTIC/...
THOUGH DEPENDING ON THE SIZE AND INTENSITY SOUTHERN PORTIONS OF
THE MID-ATLANTIC WILL BE AFFECTED. THE GFS/ECMWF DEVELOP A BROAD
LOW THAT IS STRETCHED SW TO NE OFF THE MID-ATLANTIC COAST BY
TUESDAY NIGHT. THE NAM GREATLY INTENSIFIES THE SYSTEM AND IS SLOW
TO MOVE IT AWAY FROM THE COAST. SNOW BANDS TO EXTEND WEST AND
NORTHWEST FROM THE CENTER OF THE SYSTEM WITH SRN VA AND ERN NC
AFFECTED THE MOST. INTRODUCED SLIGHT CHANCE POPS FOR SNOW FOR
TUESDAY AND TUESDAY NIGHT ACROSS OUR FAR SOUTHERN ZONES /CENTRAL
VA AND FAR SOUTHERN MD...SOUTH OF DC AND BALTIMORE/. UPSLOPE SNOW
FOR WESTERN SLOPES OF THE ALLEGHENY FRONT LIKELY ON TUESDAY BEFORE
TAPERING OFF TUESDAY NIGHT/EARLY WEDNESDAY.

CHILLY AIR PERSISTS FOR TUESDAY AND WEDNESDAY WITH HIGHS IN THE
LOWER 30S /AROUND TEN DEGREES BELOW NORMAL/ UNDER MOSTLY CLOUDY
SKIES. EXPECT BREEZY CONDITIONS ON TUESDAY AND INTO TUESDAY NIGHT
WITH WINDS 10 TO 15 MPH WITH GUSTS TO AROUND 20 MPH...WIND CHILLS
AROUND 20 FOR THE DC AREA DURING THE DAY TUESDAY...SLIPPING INTO
THE TEENS TUESDAY EVENING/NIGHT. THOSE OUT AND ABOUT ON TUESDAY
SHOULD DRESS FOR THESE COLD CONDITIONS.

MORE ZONAL UPPER FLOW THURSDAY AND FRIDAY WILL ALLOW FOR A RETURN OF
NORMAL TEMPERATURES ON THESE DAYS. UPSLOPE SNOW FOR WESTERN SLOPES
ENDS WEDNESDAY MORNING... WITH REST OF WEDNESDAY THROUGH THURSDAY
LOOKING DRY AS A SURFACE HIGH EXPANDS ACROSS THE SOUTHEAST.
UNSETTLED CONDITIONS RETURNING AT THE END OF THE WORK WEEK WITH A
COLD FRONT PASSAGE LATE FRIDAY INTO SATURDAY. PRECIP LOOKS TO BE AT
LEAST WESTERN UPSLOPE SNOW AT THIS TIME...IF/WHEN ANY MAKES IT OVER
THE APPALACHIANS AND WHAT PRECIP TYPE /RAIN OR SNOW/ IS STILL
GREATLY UNCERTAIN.

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