Deep South Winterwx Discussion 2015-2016

[lrak]

http://www.srh.weather.gov/images/fxc/e ... image5.gif
.
.

http://www.srh.weather.gov/graphicast.php?site=ewx&gc=5

Nice graphic from San Antonio

Happy New Year!

[Extremeweatherguy]

Interesting little storm showing up for mid/late next week on the 00z GFS run..

[Extremeweatherguy]

00z CMC looks even more impressive with the storm mid/late next week, showing a good chance of wintery precipitation from the southern plains through the southeast...including all the way to the gulf coast!

http://www.meteo.psu.edu/ewall/CMC_0z/cmcloop.html

[timNms]

From NWS Jackson, MS:

WEDNESDAY NIGHT
MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF
LIGHT RAIN AND LIGHT SNOW. LOWS IN THE UPPER 20S.
THURSDAY
CLOUDY WITH A 40 PERCENT CHANCE OF LIGHT RAIN AND
LIGHT SNOW. HIGHS IN THE MID 40S.

[icicle]

From MEG..


THE 00Z GFS AND ECMWF ARE IN UNUSUALLY GOOD AGREEMENT IN SHOWING
THE POSSIBILITY OF ACCUMULATING SNOW FOR PORTIONS OF THE MIDSOUTH
WEDNESDAY NIGHT INTO THURSDAY. THIS IS STILL FAR OUT AND THERE IS
STILL MUCH UNCERTAINTY...PREFER TO SEE LATER MODEL RUNS. MODELS
INDICATE THAT BY MID-WEEK A H5 LOW WILL DEEPEN ACROSS THE PLAINS
BECOMING CLOSED NEAR THE MIDSOUTH BY THURSDAY. ARCTIC
AIR...COLDEST OF THE WINTER...WILL PLUNGE SOUTHWARD THROUGH THE
PLAINS. MODELS INDICATE A 1048-1050 MB SURFACE HIGH NEAR THE
MT/ND/CANADIAN BORDER BY WEDNESDAY MORNING. MEANWHILE...A SURFACE
LOW DEVELOPS AND IS FORECAST TO TRACK EASTWARD ALONG THE NORTHERN
GULF. A DEEP COLD AIR MASS OVER THE MIDSOUTH WILL SUPPORT
PRECIPITATION TO BE ALL SNOW ACROSS THE ENTIRE REGION. THE QUESTION
THEN BECOMES HOW MUCH PRECIPITATION WE RECEIVE FROM THIS SYSTEM.
ALSO...THERE REMAINS UNCERTAINTY IN TIMING OF THE SYSTEM. THE 06Z
GFS IS TENDING FASTER BRINGING SOME SNOW INTO THE REGION AS EARLY
AS WEDNESDAY AFTERNOON. STAY TUNED... THE COLDEST AIR OF THE
WINTER...EVEN COLDER THAN EARLY NEXT WEEK...IS THEN FORECAST TO
PLUNGE INTO THE MIDSOUTH THE LATTER PART OF NEXT WEEK.

[IrishRose]

From the NWS Mobile/Pensacola/Destin area:

A POTENTIALLY VERY INTERESTING SITUATION DEVELOPS WEDNESDAY NIGHT
INTO THURSDAY. THE GFS...GEFS...AND ECWMF ARE ALL IN GOOD AGREEMENT
OF A STRONG SHORTWAVE DIVING SOUTH OUT OF CENTRAL CANADA INTO THE
MIDWEST ON THURSDAY. A STRONG UPPER LEVEL JET ON THE BACKSIDE OF THE
TROUGH HELPS TO DEVELOP A SFC LOW OVER THE WESTERN GULF...WHICH MOVES
EAST WEDNESDAY NIGHT INTO THURSDAY. GIVEN THE EXTENT OF COLD AIR IN
PLACE PRIOR TO THIS LOW...THE EXACT TRACK WOULD HAVE SIGNIFICANT
IMPLICATIONS ON OUR WEATHER. THE ECMWF AND GEFS MEAN SHOW A MORE
SUPPRESSED TRACK OVER THE NORTH CENTRAL GULF COMPARED TO THE GFS. A
SUPPRESSED SOLUTION DOES MAKE SENSE WITH THE SFC RIDGING AND AMOUNT
OF COLD AIR PRECEDING THE LOW WHICH HELPS TO SHIFT THE BAROCLINIC
ZONE FURTHER SOUTH. IF THIS WERE TO COME TO FRUITION...THEN THERE WOULD
BE A CHANCE OF SOME SNOW...ESPECIALLY OVER THE NORTHERN COUNTIES. IF
A 00Z GFS TRACK WITH THE LOW FURTHER NORTH HAPPENED...THEN WE WOULD
BE LOOKING AT MAINLY A RAIN EVENT. OUT OF RESPECT OF THE ECMWF AND
ITS AGREEMENT WITH THE GFS ENSEMBLE MEAN...HAVE INTRODUCED A CHANCE
OF RAIN AND SNOW OVER NORTHERN ZONES WED NIGHT...BUT CAPPED POPS AT
30 PERCENT. A SMALL CHANCE OF RAIN THEN CARRIES INTO THURSDAY AS
BOUNDARY LAYER TEMPS WARM. SINCE THIS IS STILL 6 DAYS OUT...A LOT OF
UNCERTAINTY EXISTS AND PLENTY OF TIME FOR THE GUIDANCE TO CHANGE
ITS TUNE. HOWEVER...THE ECWMF HAS BEEN STEADFAST IN SHOWING A LOW
FOR SEVERAL MODEL RUNS NOW AND IS GAINING SUPPORT OF OTHER MEDIUM
RANGE GUIDANCE. STAY TUNED. 34/JFB

[Brent]

Sunday Night: Mostly clear, with a low around 15.

Monday: Sunny, with a high near 39.

Monday Night: Clear, with a low around 13.

Tuesday: Sunny, with a high near 39.

Tuesday Night: Clear, with a low around 18.

and then the real fun stuff...

Wednesday Night: A 20 percent chance of snow. Mostly cloudy, with a low around 23.

Thursday: A 40 percent chance of snow. Cloudy, with a high near 39.

Today is the only day in the next week with a high above 45... amazing. Our average high is in the 50's.

[attallaman]

:cold:

Sunday Night: Mostly clear, with a low around 15.

Monday: Sunny, with a high near 39.

Monday Night: Clear, with a low around 13.

Tuesday: Sunny, with a high near 39.

Tuesday Night: Clear, with a low around 18.

and then the real fun stuff...

Wednesday Night: A 20 percent chance of snow. Mostly cloudy, with a low around 23.

Thursday: A 40 percent chance of snow. Cloudy, with a high near 39.

Today is the only day in the next week with a high above 45... amazing. Our average high is in the 50's.

Where are those temps forecasted for? Your home 20?

[Brent]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
305 PM CST FRI JAN 1 2010

.DISCUSSION...

SKIES HAVE CLEARED OUT NICELY ACROSS THE AREA...SETTING THE STAGE
FOR A COLD NIGHT. WIND WILL SLACK OFF A BIT OVERNIGHT BUT REMAIN IN
THE 5 MPH RANGE KEEPING TEMPERATURES A DEGREE OR THREE ABOVE WHAT
THEY COULD BE. TONIGHT WILL BE THE FIRST OF MANY SUB FREEZING
NIGHTS...ACROSS CENTRAL ALABAMA. AS OF TODAY...WE ARE EXPECTING
MORNING LOWS OF 25 DEGREES OR LESS AT BIRMINGHAM THROUGH THE
WEEK...INTO NEXT WEEKEND. THE RECORD NUMBER OF CONSECUTIVE DAYS
BELOW 25 DEGREES AT BIRMINGHAM IS ELEVEN...SET IN JANUARY OF
1940...WE COULD CHALLENGE THAT RECORD OVER THE UPCOMING DAYS.
ADDITIONALLY...THE RECORD FOR CONSECUTIVE DAYS BELOW 20 DEGREES IS
SEVEN...SET IN 1899. THAT RECORD LOOKS SAFE FOR NOW.

OVER THE WEEKEND A COLD DRY AIRMASS WILL OOZE INTO CENTRAL ALABAMA.
AIR ORIGINATING OVER WESTERN CANADA WILL NOT BE MODIFIED
SIGNIFICANTLY DUE TO AN EXTENSIVE SNOW PACK UPSTREAM OVER THE PLAINS
AND MIDWEST. MORNING LOWS WILL FALL INTO THE TEENS FOR A LARGE
PORTION OF THE AREA BEGINNING ON MONDAY...WITH HIGHS STRUGGLING TO
GET OUT OF THE 30S FOR MUCH OF THE AREA.

RELATIVE HUMIDITY WILL BE LOW WITH SUCH A DRY AIRMASS IN PLACE
BEGINNING SUNDAY AFTERNOON. A RED FLAG WARNING MAY BE REQUIRED FOR
RH`S LESS THAN 25 PERCENT SUNDAY AND MONDAY.

YESTERDAYS MODEL RUNS WERE IN BETTER AGREEMENT IN BRINGING A SHOT OF
WINTRY PRECIPITATION INTO CENTRAL ALABAMA WEDNESDAY NIGHT INTO
THURSDAY. LATEST RUNS LOOK DRIER...BUT WILL NOT BACK TOTALLY OUT OF
THE SNOW PREDICTION JUST YET AS WE REMAIN IN AN UNUSUALLY COLD...YET
PROGRESSIVE PATTERN.

12/SIRMON

[Dean4Storms]

Yea, the GFS shows the low down near Cuba, that seems a bit extreme. I think eventually the trend brings the low back further northward and that at least the immediate coast gets some moisture out of this.

[Ivanhater]

[Big Easy]

Pretty lame, none committal and very conservative forecast from the New Orleans NWS office.

I see many other NWS discussions from other offices in the SE, are generally more specific in their nature. For the most part, the New Orleans office is much less forthcoming on their analysis. I wonder if it has to do with the experience level of the persons working at the various offices in how these forecast are conveyed.

Anyway, here is the latest from New Orleans. They don't appear to be too over concerned/impressed, or don't even venture out beyond Wednesday AM. They say the best chance for a hard freeze in the next 7 days is on Wednesday morning. Reading between the lines, it appears as if they think this may not be that big of an outbreak of very cold air

There appears to be some conflicts. Many of the Texas offices are calling for some serious cold air for their respective areas over the next 7-8 days, all the way down to Corpus Christi/Brownsville. Some of the Mississippi and Alabama discussions are talking about the same thing. With this being the case, is it that the New Orleans office believes there will be some sort of unforeseen heating element over the SE part of the state, that will create this wall of protection from the projected cold all of the surrounding offices are seeing? I am a bit confused.

FXUS64 KLIX 012142
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
342 PM CST FRI JAN 1 2010

.SYNOPSIS...
COLD FRONT IS WELL SOUTH INTO THE GULF..WITH HIGH PRESSURE RIDGE
FROM THE DAKOTAS SOUTHWARD INTO TEXAS. SKIES HAVE CLEARED ACROSS
THE AREA. TEMPERATURES AT MID AFTERNOON GENERALLY IN THE 50S WITH
DEW POINTS UPPER 20S NORTH TO MIDDLE AND UPPER 30S SOUTH.
&&

.SHORT TERM...
HIGH PRESSURE THROUGH THE WEEKEND. LITTLE IN THE WAY OF CLOUDS
EXPECTED THROUGH SUNDAY. COLD AIR ADVECTION IS FOCUSED TO OUR
NORTHEAST...BUT WILL STILL BE COLD ENOUGH TO PROVIDE READINGS
ABOUT 10 DEGREES BELOW NORMAL. 35

.LONG TERM...
IMPULSES CONTINUE TO WRAP AROUND EASTERN CANADA UPPER
LOW...KEEPING HIGH PRESSURE OVER THE CENTER OF THE COUNTRY.
SOUTHERN STREAM SHORTWAVE MAY HAVE ENOUGH MOISTURE TO SQUEEZE OUT
A LITTLE BIT OF PRECIPITATION WEDNESDAY NIGHT OR THURSDAY.

TEMPERATURE FORECAST IS A LITTLE FRAGILE...AS 12Z MEDIUM RANGE RUNS
SHOW THE CENTER OF THE COLD AIR MAY BE A LITTLE FURTHER EAST THAN
EARLIER FORECAST. OVERNIGHT LOWS FOR MOST OF THE EXTENDED PERIOD
WILL BE BELOW FREEZING NORTH OF LAKE PONTCHARTRAIN...AND NEAR
FREEZING ON THE SOUTH SHORE. BEST CHANCE OF A HARD FREEZE WITHIN
THE 7 DAY PERIOD WILL BE ON TUESDAY MORNING. 35
&&

[CYCLONE MIKE]

big easy, they have been like this pretty much all winter. A few days before christmas they went out on a limb and talked about hard freezes and snow the day after christmas and while it was cool, nothing like they were forecsting. I asked this same thing about a week or so ago because I noticed the same thing. They always seem much more conservative. The answer I got was it depends on which model or models the office likes the best and stick to it for their forecast. Watch as the event draws near they will change their tune towards other offices. Seems they are always a day behind Lake Charles and follow them the most.

[Ntxw]

The models have forecasted several winter weather events for the deep south this winter and when the event comes close, nothing really has happened. It's been below average yes, but nothing too severe. Realistically they're not going to scream snow and ice\frigid if the track record hasn't been so good unless they are absolutely sure. Not trying to be negative (I sure do hope winter fun is in store for everyone) but we have to remember models are a tool and should not be used as a full forecast

Edit: The trend is cold, so things are falling into place.

[Dean4Storms]

Now IF it would just come to fruition!!!

[CrazyC83]

850mb temps under 10C as far south as the Yucatan and Cuba, and close to Jamaica? WOW.

[Extremeweatherguy]

00z GFS = Brrr!

Check out the large area of 510 thicknesses the model is showing just after midnight on Friday morning over the Tennessee Valley, with 540 thicknesses extending all the way to the gulf coast:



And look at the 850mb temperatures at the same time:



Yes, that's right, you're not seeing things: the -18C (0F) 850mb temperature line extends into northern Georgia, northern Alabama and the western tip of North Carolina!


This airmass definitely has potential to deliver some of the coldest temperatures witnessed in years if the 00z GFS verifies.

[CrazyC83]

With those kind of forecasts, the Florida peninsula would need a surface cold air advection to maintain a freeze though.

[Extremeweatherguy]

With those kind of forecasts, the Florida peninsula would need a surface cold air advection to maintain a freeze though.

The 00z run did actually go on to bring the cold into Florida by Saturday morning.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_180l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_180l.gif

[Extremeweatherguy]

I have a feeling lots of people in the south will like the 12z run of the GFS...







Many areas from Texas to the Carolinas to north Florida could see some wintry precipitation if this run proved to be correct.