When you thought it was over - Active pattern to continue -

[Stormsfury]

Temperatures initially will be colder than most models are outputting due to significant snowcover ... but unlike this previous storm, there won't be a new arctic high to lock down the cold air this go around - the setup is more of a spring like orientation.

I hope that the storm sets up further east but since the ECMWF/NOGAPS/GFS/ETA/UKMET are all trending already on a solution track wise - there's no reason to believe otherwise at this point that a tremendous warm surge out ahead of the storm system, especially considering the strength and the strength of the 850mb low level jet (upwards of 60 kts.) is going to transport some very warm, GOM air and moisture northward, and very rapidly I might add ... also quite likely will set an outbreak of severe weather in the Southland, and possibly the Southeast as well..

Latest Guidance and last night EC's run indicates a potential for a devastating setup of flooding rains over the MA/NE region and a potential for a significant severe weather outbreak in the Southland, maybe Southeast.

Potential for a significant snowstorm in the Upper Midwest from IL, westward into MN and Wisconsin...Upper Lakes Region ...

EC last night progging a 985mb low over IL Day 6 and 982mb in Canada northeast of Michigan on Day 7 ... here's the latest HPC discussion concerning the upcoming event.

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
230 PM EST MON FEB 17 2003

VALID 12Z THU FEB 20 2003 - 12Z MON FEB 24 2003

PATTERN AND MODEL OVERVIEW...

IN A NUTSHELL...WE ARE FOLLOWING THE 12Z/17 GFS. IT IS
CONSISTENT WITH THE ALMOST ALL MAIN THEMES OF THE 06Z
GFS...HENCE OUR REASONING FROM THIS MORNING REMAINS
VALID. ABOUT THE ONLY IMPORTANT DIFFERENCE IS THAT THE
NEW GFS RUN IS FASTER/FARTHER N WITH A CLOSED UPPER LOW
APPROACHING CA DAY 6 OR 7.

THE LONGWAVE PATTERN FEATURES A BROAD PROGRESSIVE
MEAN TROF IN THE CENTRAL STATES THRU SAT DAY 5. FOR SUN
DAY 6 AND MON DAY 7...THE NEW 12Z GFS CONTINUES TO SUGGEST
MORE UPPER RIDGE BUILDING INTO THE GULF OF ALASKA BY NEXT
WEEKEND...MORE LIKE THE ECMWF.

MOST ALL OPERATIONAL MODELS ARE CONVERGING ON A
SOLUTION THAT BRINGS A NEW MAJOR STORM INTO THE ERN HALF
OF THE CONUS TOWARDS THE END OF THE WEEK. THE ECMWF
WAS A LITTLE SLOWER/MORE CLOSED OFF ALOFT WITH THIS SYS
THAN THE 00Z/06Z GFS THU DAY 3 AND FRI DAY 4. HOWEVER BY SAT
DAY 5...IT WAS JUST A FEW DEGREES W OF THE GFS. THE LAST 3
GFS RUNS WERE IN PRETTY GOOD AGREEMENT WITH THE
OVERALL DEVELOPMENT OF THIS MAJOR SYS WED-FRI. EVEN THE
NEW 12Z/17 NOGAPS BEGAN TO CONVERGE TOWARDS THE
GFS/ECMWF SOLUTIONS BY SAT DAY 5.

THE 12Z GFS FOLLOWS THE 06Z GFS IN TRENDING TOWARDS THE
ECMWF...WHICH BUILDS A SHORTWAVE RIDGE IN THE ERN PACIFIC
MORE THAN THE 00Z GFS SAT DAY 5 AND SUN DAY 6. THIS 06Z/12Z
GFS SCENARIO ALLOWS A DOWNSTREAM SHORTWAVE TO AMPLIFY
MORE SUN DAY 6 AS IT DROPS SEWD INTO THE CENTRAL ROCKIES.
AT FIRST WE THOUGHT THAT THE ECMWF WAS OVERDOING THE
AMPLITUDE OF THIS RIDGE...SINCE IT WAS OUT OF CHARACTER
WITH THE FLATTER 00Z/17 GFS ENSEMBLE MEAN. HOWEVER...PAST
EXPERIENCE TELLS US IT IS DANGEROUS TO IGNORE THE ECMWF
WHEN LATER GFS RUNS ARE TRENDING TOWARDS IT...HENCE OUR
CHOICE.

...REGIONAL HIGHLIGHTS...

...AK...

EXPECT FAIRLY QUIET WEATHER THE NEXT FEW DAYS COMPARED
TO LAST FEW WEEKS. SIGNIFICANT PCPN SHOULD BE CONFINED TO
S CENTRAL/SERN COAST. SINCE THE 00Z/17 GFS AND ECMWF
MEANS ARE GOING THEIR SEPARATE WAYS FROM DAY 5 ON...I
SUSPECT THAT AT LEAST THE SRN COAST MAY BE MILDER AND
WETTER THAN SUGGESTED BY THE 00Z GFS NEXT WEEKEND. THE
NEW 12Z GFS SUPPORTS OUR EARLIER THINKING HERE.

...WRN US...

EXPECT AN UNSETTLED WET SPELL FOR THE NWRN QUARTER OF
THE NATION NOW INTO SUN DAY 6 ...ESPECIALLY FROM NRN CA
NWD ALONG THE CASCADE RANGES...AND OVER THE
BITTERROOTS. 12Z GFS SHOWS A SHORTWAVE THU DIGGING A BIT
MORE INTO THE SWRN STATES DAY 3 THAN ITS EARLIER
RUN...BRINGING MORE PCPN TO HIGHER ELEVATIONS OF NRN
AZ/NM. WE ACCEPT THIS TREND...AS IT IS IN LINE WITH THE NEW
UKMET.

...CNTRL/ERN STATES...

ACTIVE WEATHER PATTERN WILL FEATURE A BIG CYCLOGENESIS
THU-FRI IN THE NATIONS HEARTLAND. THERE WILL BE STRONG
WARMING/GULF INFLOW AHEAD OF IT...AND POSSIBLY A NARROW
STRIPE OF HEAVY SN TO THE LEFT OF THE TRACK OF THE CENTER
FROM KS/NE INTO THE UPPER LAKES REGION. LOTS OF GULF
MOISTURE WILL BE TAPPED...GENERATING HEAVY PCPN MOST
AREAS E OF THE MS RIVER. UPPER DYNAMICS WILL BE MORE LIKE
EARLY SPRING...FAVORING STRONG CONVECTION ACROSS THE
SERN PORTIONS OF THE NATION EXTENDING AS FAR N AS NC/VA.
RAPID WARMING OVER DEEP SNOW COVER COULD PRODUCE
MELTING/RUNOFF PROBLEMS FRI-SAT FOR AREAS OF THE MID-
ATLANTIC THAT JUST RECEIVED HUGE AMOUNTS OF SNOWFALL. IN
ADDITION...THE OH TN/VLYS MAY SEE RUNOFF PROBLEMS AS THEY
WILL BE STILL RECOVERING FROM HEAVY RAINS THAT OCCURRED
THIS PAST WEEKEND.

SOMEWHAT COLDER AIR WILL FOLLOW THE SYS...BUT THE REAL
ARCTIC SURGE WILL LIKELY HOLD OFF UNTIL SUN DAY 6 IN THE
CENTRAL STATES. THE EWD PUSH OF THE ARCTIC AIR MAY BE
RETARDED BY A WAVE DEVELOPMENT ON THE FRONT MON DAY 7
SOMEWERE OVER THE SERN/MID ATLANTIC STATES.

[Stormsfury]

Something of note: after the expected first storm- there could be a potential late season arctic outbreak that might set the stage for a big winter event - indications showing best baroclinicity in the GOM afterwards.

[chadtm80]

Thanks for the update stormsfury.. Keep them coming

[Rob-TheStormChaser]

For sure...it does look like another cold snap, but not as acute like the last. I'm just glad that the tracks are now more westerly...at least that helps us out up north here a little, but then we now have to contend with flood and melting possibilities. Gradual is the word here...thats what we want.

[Stormsfury]

Just previewed the 18z GFS run...it's mega-cold after the Midwest Storm ... -20C 850mb temperatures all the way into MO.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_174m.gif

[GAStorm]

Anyone think that the southeast may finally get a long awaited snowstorm by next week? I think everyone up north would be more than happy to send some this way!!

[Rob-TheStormChaser]

lol take ours! Your time is running out with only snips of cold spurts from here on out. Its getting tougher and tougher to keep that much cold air and also enough moisture overrunning it to substantiate a big storm down south. This last one might've been the last 'large' chanc for the season. I wouldnt be surprised to see a few smaller systems drop a few more inches in the south, but its becoming hard pressed. We'll see.

[Stormsfury]

Anyone think that the southeast may finally get a long awaited snowstorm by next week? I think everyone up north would be more than happy to send some this way!!

Up for conjecture right now ... but I myself can only hope!...
I'm tired of missing it, and/or when the opportunity comes, continually being dry-slotted!...*

[GAStorm]

lol! That has been the story all winter long!! Big storms roll in and cold dry air squeezes a few flakes of snow if we are lucky!

[GAStorm]

lol! That has been the story all winter long!! Big storms roll in and cold dry air squeezes a few flakes of snow if we are lucky!

[Stormsfury]

Uh oh ... The Day 5 ECMWF shifted the low east and south a little -- now has a 991 low over Eastern KY (and not IL) ---

http://cyclone.plymouth.edu/cgi-bin/gen ... &cu=latest

500mb heights - Closed 500mb low over Arkansas...

http://cyclone.plymouth.edu/cgi-bin/gen ... &cu=latest

Better chance of significant snows shifts further south and east (into IL, IN, MO, and maybe Arkansas get in the act)...better chance of severe weather into Mississippi, Alabama, Georgia...day 5....

[Stormsfury]

The potential continues to exist for potential severe weather in the Southland from Texas to the Carolinas, and flooding rains in Eastern Tennessee and the Mid-Atlantic where heavy snows fell from the President's Day Storm this past weekend ...

Click Here for the Overview and Discussion for the Southeast and the Mid-Atlantic.

[Rainband]

Stormfury, Keep me updated on the potential for flooding in PA. My sister lives their and her locals always get it wrong. Also keep me posted on what we in west central Florida can expect. Rob you keep me posted too, Thanks guys

[Stormsfury]

Rob can keep you posted on Pennsylvania ... my confidence in that area is very low.

Updated Discussion for the Southeast and Mid-Atlantic