December: New Years Eve Outlook

[srainhoutx]

I believe wxman57 won a 'friendly wager' with his forecast of the 2004 Christmas Eve miracle snow that whitened the beaches from Corpus to Sabine Pass a week out as well. Winter Weather forecasting for most of our Region is tricky at best, but some memorable events such as January 1973 are often the ones where no one expects it and we are pleasantly surprised when they happen. That said we cannot get wintry mischief without the cold air and it does appear that we may have that in place by this time next weekend.

[Texas Pirate]

How come, so far, forecasters have nailed the winter forecast and the cane season was such a bust?
I'm running out of sweaters and its only the 1st of December.

[Kludge]

Brrr...a full latitude trough even during the day 10 time frame with an Arctic Outbreak fully underway across the Inter Mountain West and Plains tends to raise an eyebrow.

Mr. Meteogram with a post showing we never get below 40 degrees in 3..2..1...

[don]

0z GFS looks rather icy across central and southeast Texas next weekend

[ticka1]

0z GFS looks rather icy across central and southeast Texas next weekend

music to my ears!!!!

[sambucol]

0z GFS looks rather icy across central and southeast Texas next weekend

music to my ears!!!!

Mine, too, Ticka!!!

[TexasBreeze]

GFS highs (DW Hooks) low to mid 30's with overrunning precip. Freezing rain Sat, Sun, and Monday. Very shallow, but strong arctic front.

[Andrew]

GFS highs (DW Hooks) low to mid 30's with overrunning precip. Freezing rain Sat, Sun, and Monday. Very shallow, but strong arctic front.

Not so confident with the handling with the middle layers of the atmosphere. Models really seem to slow down the movement of the Front and trough once it hits the Texas border. We learned from this last event how wrong that can be at times. Forcing from the gulf (while strong) doesn't look strong enough to stop the progression of the colder air (especially from a source region like Northern Canada)

[Portastorm]

Yeah, the KAUS meteogram based on the 0z GFS actually shows ice pellets and freezing rain for 12/9-12/11.

"Fun" times ahead.

[don]

0z Euro looks onboard also, temps are slightly warmer than Gfs though (mid to upper 30s) instead of the GFS low to mid 30's.

[Andrew]

0z Euro looks onboard also, temps are slightly warmer than Gfs though (mid to upper 30s) instead of the GFS low to mid 30's.

Not to mention the full latitude trough that comes across the U.S. around day 9 or 10. The Euro has been very persistent with this as of late. Starting next week/ weekend we could be in store for some really cold temps.

[wxman57]

Unfortunately (to me), next weekend is looking like a very cold and wet one. Strong front moves through by sunrise Friday and the temperature falls through Sunday. The cold air layer will probably be very shallow down here, so the main threat may be freezing rain and sleet vs. snow:

[srainhoutx]

The guidance has converged on a significant Arctic Outbreak and a strong Winter Storm will drop SE from British Colombia into the Pacific NW, Northern/Central Rockies and the Northern/Central Plains lending to a multi day significant snow event that will spread across the Western and Central Regions of the Lower 48 during the first week of December. The HPC/HPC Winter Weather Outlooks this morning provide some information that is different from what we saw with the events prior to Thanksgiving week. It appears that Blizzard conditions are possible across the Northern Rockies into the Dakotas and possibly marching S into Nebraska and Kansas as the week progresses towards mid week. With our first Arctic intrusion, there was light if any snow to work with across the Plains and unlike this Arctic Outbreak, there is a surface low pressure system that will provide the first shot of much colder air with plentiful moisture ~vs~ just an over running precip situation that developed last weekend across the Southern Plains into Texas and Arkansas.

The attachment 12012013 030Z lowtrack_ensembles.gif is no longer available

The attachment 12012013 day1_psnow_gt_04.gif is no longer available

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
415 AM EST SUN DEC 01 2013

VALID 12Z SUN DEC 01 2013 - 12Z WED DEC 04 2013


DAYS 1 TO 3 ...

...PACIFIC NORTHWEST/NORTHERN TO CENTRAL ROCKIES/NORTHERN
PLAINS/UPPER MIDWEST...

HEAVY SNOWS ARE LIKELY ON DAY 1 FOR THE HIGHER ELEVATIONS OF THE
PACIFIC NORTHWEST/NORTHERN ROCKIES AS A 130-150 KT 300 MB JET
STREAMS ONSHORE INTO WA STATE FROM THE NORTHEAST PACIFIC
WITH THE JET DRIFTING SOUTH ACROSS WA/ID/WESTERN MT AND THEN INTO
NORTHWEST WY.

THE HEAVIEST SNOWS ON DAY 1...ARE EXPECTED TO FOCUS MAINLY ALONG
THE NORTHERN CASCADES
WHERE STRONG DIVERGENCE ALONG THE LEFT EXIT REGION OF THE JET
ALONG WITH OROGRAPHIC LIFT INTERACTS WITH A DEEP MOISTURE PLUME
CARRIED BY A LONG WESTERLY FETCH INTO THE REGION...TO ENHANCE THE
HEAVY SNOW THREAT OF 1-2 FEET ACROSS THE REGION.

BY DAY 2...MON...AS THE JET DRIFTS SOUTH ACROSS OR AND INTO
SOUTHERN ID AND WESTERN WY...THE WESTERLY STREAM OF MOISTURE AND
UPSLOPE FLOW ON TERRAIN FACING THE FLOW
PRODUCES A RISK FOR A FOOT OR SNOW IS INDICATED ALONG MUCH OF THE
OR CASCADES AND ALONG THE ROCKIES FROM NORTHERN ID/WESTERN MT INTO
NORTHWEST WY/NORTHERN UT WASATCH.

A SECOND AREA OF SNOW BREAKS OUT IN ADVANCE OF THE IN A REGION OF
LOW-MID LEVEL CONVERGENCE/UPPER DIVERGENCE NEAR THE 700 MB FRONT
ACROSS NORTHERN ND AND MN. SUBSTANTIAL TIMING DIFFERENCES DEVELOP
WITH THE GFS STILL ON THE FAST EDGE OF THE SUITE OF SOLUTIONS.

BY DAY 3...THE FLOW SPLITS WITH A PRIMARY NORTHERN CIRCULATION
REDEVELOPING WITH A TRAILING WAVY FRONT MOVING SOUTH ACROSS THE
GREAT BASIN AND CENTRAL ROCKIES.
THE TIMING AND INTENSITY DIFFERENCES CONTINUE ACROSS THE NORTHERN
PLAINS/UPPER MS VALLEY/UPPER GREAT LAKES. THE ECMWF SPED UP ITS
FORWARD PROGRESSION OF THE 700 MB LOW ACROSS EASTERN MT AND ND TO
BE CLOSER TO THE UKMET AND CANADIAN GLOBAL TIMING...WITH THE
NAM/GFS AND THEIR RESPECTIVE GEFS/SREF MEANS STILL AHEAD OF THIS
CLUSTER. STRONG CONVERGENCE NEAR THE 700 MB FRONT/CIRCULATION
DRIVES SNOW ACROSS CENTRAL UT TO NORTHERN CO...WITH THE 00Z ECMWF
DEVELOPING 130 KT JET MAXIMA AND ASSOCIATED DIVERGENCE MAXIMA OVER
THE UT WASATCH TO THE RANGES OF NORTHERN CO/ADJACENT SNOW RANGE OF
SOUTHEAST WY. WITH THE FASTER TREND IN SINKING THE FRONT SOUTH
SHARED AMONG THE 00Z ECMWF/UKMET/CANADIAN...THESE SOLUTIONS WERE
GIVEN EQUAL WEIGHTING IN THE FORECAST.


The 00Z ensembles and operational guidance suggest that as the week progresses, bitter cold Arctic air will settle across our Region and bring the potential of a multi day Winter Weather Outbreak that will extend very far S into the Southern Plains and possibly into Northern Mexico. By late in the upcoming week the trends suggest that freezing rain/sleet/snow will spread much further South into Texas, Oklahoma, Kansas, Missouri, Northern Louisiana an Arkansas. Temperature departures should range in the -20 to -30 F range with overnight lows approaching the -30 F range across the Northern/Central Rockies extending East into the Northern Plains. There are increasing odds that a widespread societal impact event could develop that will extend into the upcoming weekend very far S into Texas as several short waves drop S into the base of the trough and reinforce the very cold air and connect with a noisy sub tropical jet that may provide for freezing rain, sleet and snow as an over running pattern develops late Thursday into next Sunday and possibly extending into the early days of the second week of December. We will see, but the signals and available data as well as some increasing chatter from the NWS offices across the Region suggest after a few days respite from the cold air with warmer temps and slight rain chances, we may once again plunge into the deep freeze and with less air mass modification and 'colder' surface temps may provide for Wintry mischief other than from a cold core upper low passing overhead.

[sambucol]

Is this pipe busting cold?

[srainhoutx]

Is this pipe busting cold?

I do not believe this will be a pipe busting event. The air mass is rather shallow and may well keep us in the 30's ~vs~ the low to mid 40's as we saw with the last event unless we see some major changes in the next several days.

[Portastorm]

I understand and appreciate the need for Texas-based NWSFOs to cautiously approach forecasts for wintry weather. No need in going "hog wild" five days out when things can (and often do) change. But in the case of my own local office, EWX, I think their take right now on Friday night-Saturday temperatures are going to bust horribly. They're waaaaay too warm. Forecasting a high in the low 40s on Saturday when even the warmest guidance (GFS) shows highs in the low 30s is a bit of a head scratcher.

I'm fairly confident they'll be moving those temps downward with each approaching forecast cycle. But it does create a disconnect when you tell people "get ready for next weekend" and they come back with "oh, I saw the forecast and the temperatures aren't even close to freezing."

[wxman57]

Unfortunately, I think the temps will be close to freezing next weekend, Portastorm. As for the general public - not much they can do about it this far out. Maybe by Friday. Our clients, though, will appreciate the early heads-up, as they can make preparations for the cold. Some of their lines freeze when temps reach the mid 40s, and prolonged highs below 45 or so can cause problems generating enough steam at refineries.

[Portastorm]

Unfortunately, I think the temps will be close to freezing next weekend, Portastorm. As for the general public - not much they can do about it this far out. Maybe by Friday. Our clients, though, will appreciate the early heads-up, as they can make preparations for the cold. Some of their lines freeze when temps reach the mid 40s, and prolonged highs below 45 or so can cause problems generating enough steam at refineries.

Yep. And that is when/where I like private sector meteorologists who are more willing to take that chance and make a call from a longer range. I do understand though that it is what your clients expect/pay for.

FWIW, I am not forecasting at this time a winter storm for Austin next weekend! I do think there is a decent chance of some kind of wintry precip (most likely freezing rain, like you said). Guidance suggests QPF amts will be light. But I do feel confident in saying it's going to be quite cold -- as cold if not colder than the last "outbreak." What the jet stream does and the flow from the Southwest ... remains to be seen.

Glad y'all are looking out for our friends in the fossil fuel business!

[Andrew]

Unfortunately, I think the temps will be close to freezing next weekend, Portastorm. As for the general public - not much they can do about it this far out. Maybe by Friday. Our clients, though, will appreciate the early heads-up, as they can make preparations for the cold. Some of their lines freeze when temps reach the mid 40s, and prolonged highs below 45 or so can cause problems generating enough steam at refineries.

Yep. And that is when/where I like private sector meteorologists who are more willing to take that chance and make a call from a longer range. I do understand though that it is what your clients expect/pay for.

FWIW, I am not forecasting at this time a winter storm for Austin next weekend! I do think there is a decent chance of some kind of wintry precip (most likely freezing rain, like you said). Guidance suggests QPF amts will be light. But I do feel confident in saying it's going to be quite cold -- as cold if not colder than the last "outbreak." What the jet stream does and the flow from the Southwest ... remains to be seen.

Glad y'all are looking out for our friends in the fossil fuel business!

Yea QPF is going to be hard to predict this far out, especially when it comes to predicting shortwave tracks and amount of moisture available.

[don]

Gfs has temps in the mid 30's for Houston with plenty of precip. the question is are the models underestimating the cold air due to its shallow nature? just a few degrees can make the difference between an ice storm or just a cold rain.