Deep South Winterwx Discussion 2015-2016

[southerngale]

Chat with us about the weather.

[srainhoutx]

Impact Weather has just issued a new video regarding this weeks expected events from TX to points East...

http://www.youtube.com/impactweather

[Brent]

Thursday Night...Occasional rain or snow. Lows in the lower 30s. Chance of precipitation 90 percent.

[Ivanhater]

Say it aint so...another big snowstorm for the Deep South next week?

00z Canadian says why not?!

[MississippiWx]

Hey, Ivan. Isn't that the ECMWF model you posted?

[Raebie]

Seriously. Say it ain't so.

[Brent]

Birmingham:

THE LATEST NAM AND GFS MODEL SOUNDINGS HAVE COME AROUND TO THE
IDEA EARLIER POSED BY THE ECMWF THAT SATURATED CONDITIONS WILL
EVENTUALLY OCCUR IN A SUFFICIENTLY COLD DEPTH TO SUPPORT THE
FORMATION OF SNOW CRYSTALS. THE SAME MODEL SOUNDINGS ALSO SHOW
THAT THERE WILL BE A RATHER SHORT (1 TO 3 HOUR) WINDOW OF
OPPORTUNITY...RIGHT AS THE PRECIP IS ENDING...FOR THOSE SNOW
CRYSTALS TO WALK THE TIGHTROPE OF 32 DEGREES F DOWN TO THE
SURFACE. IT WILL BE A CLOSE CALL...AND I WILL NOTE THAT THE ECMWF
IS ACTUALLY A BIT WARMER THAN THE OTHER MODELS (AT THE SURFACE) AT
PRECIP CUT-OFF TIME. ANY SNOW THAT DOES MAKE IT ALL THE WAY DOWN
SHOULD BE SHORT-LIVED...WITH A DUSTING TO (WORST-CASE SCENARIO)
MAYBE A HALF INCH AT MOST. THE COLD AIR WILL BE FOLLOWING IN
BEHIND...SO ANYTHING THAT ENDS UP WET ON THE GROUND COULD BECOME
FROZEN BY MORNING.

THE PARADE OF SHORTWAVES CONTINUES INTO EARLY NEXT WEEK...WHICH
TAKES US TO OUR SECOND OF THE TWO WINTER WEATHER POTENTIAL
SYSTEMS. THE GFS AND ECMWF ARE SIMILAR IN BRINGING A SURFACE LOW
ACROSS THE NORTHERN GULF IN THE MONDAY THROUGH TUESDAY TIME FRAME.
THE TRICKY PART WITH THIS SYSTEM...THOUGH...IS THE APPARENT
PRESENCE OF A COLD AIR DAMMING WEDGE ALONG THE EAST COAST. AS
ACTIVE AS THIS WINTER HAS BEEN ALREADY...THIS IS A FEATURE WE
REALLY HAVE NOT HAD TO DEAL WITH -- YET.

CAD WEDGES COMPLICATE THINGS...LARGELY BECAUSE THE LONGER RANGE
MODELS DON`T HAVE THE BEST RESOLUTION TO DEAL WITH THEIR LARGELY
MESOSCALE AFFECTS (ESPECIALLY IN THE LOW LEVELS). TAKING THE 12Z
RUN MODEL OUTPUT AT FACE VALUE...SURFACE TEMPERATURES ARE FORECAST
TO BE ONLY A 3-4 DEGREES F ABOVE FREEZING. THAT DOESN`T LEAVE A
LOT OF WIGGLE ROOM FOR MODELS THAT POTENTIALLY CAN`T RESOLVE THE
COLDNESS OF A CAD WEDGE COMING INTO EAST ALABAMA. FOR THIS
REASON...I HAVE INTRODUCED THE POSSIBILITY OF FREEZING RAIN (ALONG
WITH THE LIKELIHOOD OF RAIN) FOR THE NORTHEAST PORTION OF OUR CWA
FOR MONDAY NIGHT AND TUESDAY MORNING. IT IS A LOW CONFIDENCE AND
LOW CHANCE ENDEAVOR AT THIS POINT...BUT POTENTIALLY HIGH IMPACT
IF COLDER SURFACE TEMPERATURES OCCUR.


Thursday Night...Rain likely in the evening...then rain likely or chance of snow after midnight. No snow accumulation. Lows around 30. Northwest winds 5 to 10 mph. Chance of precipitation 60 percent.

Monday Night...Rain likely and chance of light freezing rain. Lows in the lower 30s. Chance of precipitation 70 percent.

Tuesday...Cloudy. A 40 percent chance of rain and light freezing rain in the morning. Highs in the upper 40s.

[zippity]

Oh my.

[Metalicwx220]

Area forecast discussion
National Weather Service Charleston SC
638 PM EST Wednesday Jan 19 2011


Synopsis...
high pressure will shift offshore by late Thursday. A cold front
will move across the area early Friday...followed by another high
pressure through the weekend. Another low pressure system could
affect the region early next week.


&&


Near term /until 6 am Thursday morning/...
high pressure will continue to build across the region
tonight...with only cirrus streaming over the area. Winds should
decouple by late this evening resulting in light/variable winds
over land. These two conditions will result in great radiational
cooling. Temperatures will fall quickly tonight with lows near
freezing far inland to near 40 degrees along the immediate coast.


The primary concern tonight will be lingering low level
moisture left by overnight rain which should promote ground fog...
particularly in southeast Georgia where cloud cover persisted through the day
today and drying has been minimal. Overnight...guidance depicts
drier air spreading across the region and ending the potential for
significant fog from north to S.


&&


Short term /6 am Thursday morning through Saturday/...
Thursday and Thursday night...high pressure pushing east across the Ohio Valley
will skirt the southeast Thursday...moving offshore Thursday
evening...while an area of low pressure coming off The Rockies
strengthens over the Southern Plains. This will result in an
increase in high clouds throughout the day but the system will
remain well to the west to prevent any precipitation from reaching the SC/Georgia
coast during the day on Thursday. Going into Thursday night...the
center of the developing low will shift into the northern Gulf while
its associated upper level trough axis pivots through the
Mississippi River valley. Along and ahead of this upper trough...
deep moisture will increase while the surface low pressure area shifts
northeastward along a cold front being dragged through the eastern
states. Isentropic lift will moderately increase...but of concern is
the more sparse nature that the models /including the NAM...GFS...
sref and European model (ecmwf)/ are dispersing potential precipitation. The speed
and track of the low...including its displacement from the upper
trough...also looks to impact the precipitation distribution.
Therefore...have opted to bump probability of precipitation back down to the middle-chance range
which is in line with numerical guidance. Temperatures will remain
mild ahead of the front...with highs in the low 60s and lows in the
middle-upper 40s.


Friday and Friday night...the cold front will shift offshore
Friday...being pushed along by the definitive upper level trough
axis. High pressure expanding over the Ohio Valley region will then
spill over the Appalachians into the southeast...allowing cold air
advection to once again develop. Despite clearing skies...highs will
only reach the middle-upper 50s. Clearing conditions will continue into
Friday night...with the area of high pressure pushing further east into
the middle Atlantic region and building down the Appalachians...taking the
form of a weak high pressure wedge. This will result in low
temperatures Friday night dropping to well below normal values in
the upper 20s to lower 30s.


Sat...high pressure with cold air advection will continue over land
Saturday while a weak trough meanders well offshore...allowing for
clear but cool conditions over land with cloudy/showery conditions
well offshore. Upper level flow out of the northwest will win the
battle over strong sunshine and any downsloping influences...
keeping maximum temperatures around 50 degrees. Should surface winds remain more
prominently northeast...if there is additional cloud cover...or if
cold air advection is stronger than anticipated...highs could remain
only in the 40s.


&&


Long term /Saturday night through Wednesday/...
lingering showers are possible over the coastal waters Saturday
night before dry high pressure continues to build into the region
from the northwest. Expect rain/shower activity to be at a minimum
and well offshore through Sunday while high pressure dominates the
region.


The forecast becomes highly uncertain for the beginning of next week
with another system possibly developing over the south central
United States and affecting the southeast as early as Monday night.
At this time the system favors an eastward track along the northern
Gulf of Mexico and into southern Georgia before shifting northeast
along the coast early Wednesday. Should the system develop...the
track will be dependent on the strength of The Wedge over the
southeast United States Tuesday and Wednesday. Scattered
rain/showers have been introduced Monday night through Tuesday due
to the anticipated track of this system. The system looks to eject
into the Atlantic by Wednesday.


Temperatures will continue to generally run below normal through the
period.


Weather.com has a rain/snowshowers in the forecast for Charleston and it misses Savannah somehow for Saturnday.

[Brent]

[Ivanhater]

[BigB0882]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0? It is still a ways out but it looks mighty cold, GFS has highs in BTR of upper 30's with about 1.00" of rain. If this could trend a little colder it would be nice. Too much time for things to change for me to get excited, though.

It is hard to not get excited when you have 1.00" of QPF that is so close to being snow. That would be an epic event for anyone this far south.

[Ivanhater]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0?

Usually when I see the pocket of 0c, it is usually indicative of a cold core Upper level low. If I am not mistaken, that is what gave Houston and New Orleans their big snow a couple years ago.

[Dean4Storms]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0?

Usually when I see the pocket of 0c, it is usually indicative of a cold core Upper level low. If I am not mistaken, that is what gave Houston and New Orleans their big snow a couple years ago.

Yep, looks like an UL LOW generating a surface reflection over the northern Gulf.

In this type situation, you could potentially be just above freezing at the surface like in the mid 30's and have snowflakes falling. They might not stick unless is is coming down pretty hard and then mostly just on grassy surfaces. So anyone just outside of that 0 degree C line could still see some flakes.

[Metalicwx220]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0?

Usually when I see the pocket of 0c, it is usually indicative of a cold core Upper level low. If I am not mistaken, that is what gave Houston and New Orleans their big snow a couple years ago.

Yep, looks like an UL LOW generating a surface reflection over the northern Gulf.

In this type situation, you could potentially be just above freezing at the surface like in the mid 30's and have snowflakes falling. They might not stick unless is is coming down pretty hard and then mostly just on grassy surfaces. So anyone just outside of that 0 degree C line could still see some flakes.

Does it have snow for the entire state of Georgia or is that all rain?

[Jag95]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0?

Usually when I see the pocket of 0c, it is usually indicative of a cold core Upper level low. If I am not mistaken, that is what gave Houston and New Orleans their big snow a couple years ago.

Yep, it was a thing of beauty for New Orleans. We didn't get a flake further east in Mobile, but it dumped 8" on the north shore of the Lake. Wish I would have saved radar loop of that.

[Metalicwx220]

What's up with that pocket of 0c? How does that happen, a cold core low? If it could move a little south BTR would be in it. However, is the precip before or after temps get to 0?

Usually when I see the pocket of 0c, it is usually indicative of a cold core Upper level low. If I am not mistaken, that is what gave Houston and New Orleans their big snow a couple years ago.

Yep, it was a thing of beauty for New Orleans. We didn't get a flake further east in Mobile, but it dumped 8" on the north shore of the Lake. Wish I would have saved radar loop of that.

LOL thats how I feel every snowstorm that comes. Charleston gets every thing and we get Rain.

[Dean4Storms]

[/quote]

Yep, looks like an UL LOW generating a surface reflection over the northern Gulf.

In this type situation, you could potentially be just above freezing at the surface like in the mid 30's and have snowflakes falling. They might not stick unless is is coming down pretty hard and then mostly just on grassy surfaces. So anyone just outside of that 0 degree C line could still see some flakes.[/quote]
Does it have snow for the entire state of Georgia or is that all rain?[/quote]


Prolly some snow for the northern 1/3 of GA. as I would imagine this begins tracking NE.

[MGC]

Yep, cold UL that caused all that snow in Dec 08...sister in Hammond La had quite a snow, most I've ever seen in SE LA.....MGC

[MississippiWx]

Unfortunately, the 18z run already backed off the snow event for next week. It just doesn't seem like anyone south of I-20 will get much, if any, snow this year. The pattern has been close several times, but just not close enough.