December 2017: End Of The Year Weather

[Heat Miser]

I agree that it does create a lot of chatter, but wishing or wish-casting something as devastating as an 83 freeze comes this way borders on lunacy. A few freezes a year, fine, kills off mesqitto's and what not, so I've heard. Getting giddy about the possibility of a devastating freeze or ice storm, no. Telling everyone you love them in the midst of a legitimate snowfall, I have no problem with. Despite the fact I had to get up at 6 AM the next morning I sat/stood and watched like a child waiting on Santa until I had to at least get a few hours sleep.
And, unless building codes have significantly improved since 83, and those houses that stood then still stand have received incredibly improved insulation to combat a freeze such as 83, devastation will still be widespread.
Ice on the roadways, I see absolutely nothing positive about such a scenario in an area ill prepared and drivers inexperienced driving in such conditions. Even drivers experienced in those conditions would rather not drive on black ice. Hundreds of accidents with many being majors, injuries and unfortunately fatalities.
Power lines down leaving thousands without heat for maybe days at a time.
You want to get giddy about snow, hey I'm right there with you. You want to get excited about a devastating freeze or an ice storm, I'm not. And, I'm the biggest weather enthusiast there is.

[sau27]

How about the Canadian spitting out a 1070mb high with temps in the -50s in Montana and Wyoming. Highly unlikely but still incredible to see a model putting that out. Ooof.

[DoctorMu]

Yeah, the Canadian is running really cold, and in the teens down to Hempstead. A bit of ice.

GFS runs a little warmer with sleet Christmas night and the 26th.

Even the GEFS ensemble brings the freeze line nearly to the coast.

[DoctorMu]

How about the Canadian spitting out a 1070mb high with temps in the -50s in Montana and Wyoming. Highly unlikely but still incredible to see a model putting that out. Ooof.

Lol GFS and Ensemble a balmy -10°- 0°F.

No doubt some cold air will be piling up this week with the hounds released this weekend. Anything is in play. Cold rain, sleet, freezing rain, w/e, PPP weather. I'm sure emergency management will be preparing - we still have a lot of displaced folks. Shelters will be open. Help your neighbor if you can!

[Ptarmigan]

I'll say this to be in regards to what all the guidance has been suggesting, if this cold is going to build across Western Canada we will know by Tuesday. That is when the strong disturbance currently over the Eastern Bering Sea/Western Alaska is expected to head ESE toward British Columbia and develop the strong trough the models have been predicting.

Meanwhile I have glanced at the overnight Ensembles and even the CPC Day 8+ GEFS Super Ensemble and those ensemble means are different that the Operational depictions of the GFS and the ECMWF. Cold air is there starting Tuesday (Western Canada) and heading S on Wednesday/Thursday into the Lower 48. There is quite a bit of moisture over Texas as well into the week after Christmas. Monday we will be 8 Days out until Christmas Day. If the guidance converges on a realistic solution by Tuesday/Wednesday, then and only then will confidence increase moderately regarding our sensible weather. Also a note of caution when looking at the Medium Range and beyond with those extreme heights (1060+ High Pressure). Those events are extremely rare. The strongest High Pressure ever recorded if I recall correctly was 1078mb over Alaska/Western Canada back in 1989, or maybe 1983.

A 1060 millibar is statistically an outlier. There have been freezes with this type of pressure. Very rare.

The highest recorded pressure in North America is 1079.6 millibars on February 2, 1989 in Dawson City, Yukon, Canada. America's highest is 1078.6 millibars in Northway, Alaska in January 31, 1989. That gave Texas a freeze in early February 1989.

The highest pressure in the Lower 48 is 1064 millibars in Miles City, Montana on December 24, 1983. That was a really huge freeze like January 1886, February 1895, February 1899, and January 1930.

I am sure there have been higher pressure like in January 1886, February 1895, February 1899, and January 1930. I would not be surprised if it went up to 1100 millibars.

World and U.S. Anti-cyclonic (High Barometric) Pressure Records
https://www.wunderground.com/blog/weath ... cords.html

[Andrew]

Continual support for a cold front pushing through the region this weekend according to the GFS. This would keep temperatures at or below normal for Christmas. Indications for Christmas morning show a freeze for the majority of SE Texas. Looking more and more likely that Christmas will actually feel like Christmas this year if the GFS is correct. On the other hand the CMC continues to delay the front and shows it arriving Christmas day. I suspect the GFS is on the right track. May be over-exaggerating the intensity and depth of the cold air but I do suspect it is getting closer to a solution.

[stormlover]

Gfs has been so inconsistent just like all the models, hard to trust any of them right now, Thursday we will get an idea

[Andrew]

Gfs has been so inconsistent just like all the models, hard to trust any of them right now, Thursday we will get an idea

GFS has actually been rather consistent with that first front pushing through the 23-24th. Still think that has a good chance of occurring.

[Katdaddy]

Unsettled and messy weather to start the week. Expect increasing rain chances today with areas of fog which will continue through Tuesday. The SPC still has SE TX in a marginal risk area Tuesday evening. Wednesday is looking very nice with low 70s and mostly sunny skies. Nothing new for the upcoming weekend as unknowns persist this far out.

[snowman65]

I'm not seeing anything below freezing for the rest of the year. My how things have changed.

[srainhoutx]

Little doubt we will see several strong fronts during the Christmas Holiday Period. The problem is the chatter that began a little over a week ago with those wintry weather graphics in the Long Range Guidance. Will those pictures of ice and possibly snow come back on those model graphics in a couple of days for this weekend and Christmas Day? I'm not so sure about that. Below are the morning Update surface charts from the Weather Prediction Center for Days 4 through 7 that takes us into Christmas Morning. I do see a 1048mb Artic High depicted near Montana on Christmas Morning. Yesterday the WPC went unusually high with a 1040mb High Pressure Cell, so perhaps there is some validity to the reasoning of much colder air arriving around and after Christmas. I also pulled up the QPF Graphic for the 23rd through the morning of Christmas. There is some light moisture across our Region with higher amounts NE of us. The Experimental Winter Weather Graphics at Day 6 and 7 suggest some possibility of snow across portions of Eastern Oklahoma and Arkansas but nothing across Texas.

12182017 Day 4 Surface Chart 9khwbg_conus.gif

12182017 Day 5 Surface Chart 9lhwbg_conus.gif

12182017 Day 6 Surface Chart 9mhwbg_conus.gif

12182017 Day 7 Surface Chart 9nhwbg_conus.gif

121820107 Day 6 to 7 QPF 97ep48iwbg_fill.gif

[srainhoutx]

Michael Ventrice‏Verified account @MJVentrice · 38m38 minutes ago
Global ensemble models are still struggling with resolving the timing of an arctic cold front over the eastern U.S. on Christmas Day. Our @WxCoEnergy Cluster product illustrates the discrepancy within the GFS and ECMWF Ensembles.

[snowman65]

Michael Ventrice‏Verified account @MJVentrice · 38m38 minutes ago
Global ensemble models are still struggling with resolving the timing of an arctic cold front over the eastern U.S. on Christmas Day. Our @WxCoEnergy Cluster product illustrates the discrepancy within the GFS and ECMWF Ensembles.

Has anyone changed the batteries lately?

[tireman4]

FXUS64 KHGX 181045
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
445 AM CST Mon Dec 18 2017

.DISCUSSION...
Areas of fog, dense at times, was noted across northern parts of
the area early this morning. Patchy sea fog is starting to
develop in the Gulf and this will likely expand and become more
dense in the next 12-24 hours.

Based on the latest rigs & buoy obs, it appears that the warm
front is situated just north of 42019 this morning. Latest
guidance suggests it`ll make slower northward progression than
what we were thinking yesterday. It appears the boundary might not
approach the coast until late afternoon now, so trimmed POPs down
some northwest of Highway 59/69. Concerned the numbers south of
there could be a touch too high as well based on some of the
hires data, but will let the 50-60% POPs ride there for now.

Look for some showers and thunderstorms to initiate south of the Big
Bend area overnight complements of an upper impulse making its up
in the southwest flow aloft. These showers and thunderstorms will
probably clip our nw/n zones late tonight into Tuesday morning.

Large scale lift will increase during the day Tuesday and Tuesday
night as the upper trough situated over southern Arizona & New
Mexico makes its way across north Texas. Look for shra/tstms to
continue across the NW half of the area thru much of the
day...eventually building further southwestward into a thin line
of storms along a surface front. This boundary should push
ese through the region between 5pm-11pm Tue. Parameters are still
in place for the possibility of some strong/severe cells. (There
should be more instability to tap into than what we saw Saturday
night). Areas of sea fog will be an issue coastal areas, outside
of rainfall, later today until the front pushes thru late Tue
night.

Wednesday is looking nice with lows in the 50s & highs in the 70s
along w/ msunny skies. Thursday also looks dry and warm, though
it`ll be a transition day with onshore winds resuming and an
increase in clouds and moisture levels.

A stronger cold front, and associated precip in advance of the
windshift, should push thru southeast Texas during the day
Friday. There remains some fairly significant differences in
opinion between models as to this fronts strength in regards to
temps in its wake. Some, like the ECMWF even bring a warm front
quickly back through se Tx late Saturday. Instead of chasing run-
to-run guesses this far out, the extended fcst (from Saturday and
beyond) was left essentially the same. The set up remains favorable
for a couple of reinforcing shots of colder temps making their
way into the region going into next week. But overall forecast
confidence in timing & specific details hasn`t improved much, and
probably won`t do so for at least a few more days. 47

&&

.MARINE...
Generally light east and then southeast winds will prevail across
the coastal waters through tonight. This pattern will remain fav-
orable for the development of sea fog late this afternoon/tonight
across the bays/nearshore waters. This potential for sea fog will
likely stay in place through until late Tues...when the next cold
front is expected to move across SE TX. A light/moderate offshore
flow will prevail in the wake of the front through Weds.

Onshore flow should return early Thurs, and wind speeds should be
strengthening to SCEC criteria Thurs night/early Fri. Models are
now pushing this second stronger front into the coastal waters by
Fri night. Moderate/strong N winds will fill in behind this front
Sat. SCEC/SCA flags will likely be needed at that time. 41

&&

.AVIATION...
A messy forecast will be continuing through the next TAF package
with the low clouds/fog potential remaining in place through the
rest of the morning/early afternoon. The development of overrun-
ning rains across much of the CWFA along with the passage of the
warm front inland should help to keep MVFR/IFR CIGS in place for
this afternoon/evening. Will also have to keep tabs on GLS where
the potential for sea fog remains in place until the cold front).
41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 62 61 72 53 72 / 40 70 70 70 0
Houston (IAH) 67 63 75 59 73 / 60 50 40 70 0
Galveston (GLS) 66 65 73 62 71 / 60 20 30 60 0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 10 AM CST this morning for the
following zones: Brazos...Burleson...Grimes...Houston...
Madison...Montgomery...Polk...San Jacinto...Trinity...
Walker...Washington.

GM...NONE.

&&

[srainhoutx]

The newly Updated Weather Prediction Center Extended Range Discussions suggests Artic Air is coming and some wintry mess with it, but the finer details are still highly uncertain...

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1102 AM EST MON DEC 18 2017

VALID 12Z THU DEC 21 2017 - 12Z MON DEC 25 2017

...ABOVE AVERAGE CONFIDENCE IN THE POTENTIAL FOR AN OUTBREAK OF
ARCTIC AIR ACROSS THE CENTRAL U.S. BY THE WEEKEND...


...OVERVIEW...

MODELS CONTINUE TO LOCK ON TO A SIGNIFICANT AMPLIFICATION OF THE
FLOW PATTERN THROUGH CHRISTMAS MORNING - RIDGE EXTENDING FROM THE
WEST COAST TO THE ARCTIC AND A MEAN TROUGH FROM THE HUDSON BAY
AREA TO THE DESERT SOUTHWEST/MEXICO. THIS SETUP WILL FAVOR COLD
AIR TO SURGE SOUTHWARD... WHICH WILL CREATE A SHARP THERMAL
GRADIENT ACROSS THE SOUTHERN TIER STATES AS WARM, MOIST AIR LIFTS
NORTHWARD (THANKS TO A STRENGTHENING SUB-TROPICAL RIDGE OFFSHORE
THE SOUTHEAST COAST). THIS BOUNDARY WILL MORE OR LESS REMAIN
ACROSS THE SOUTHERN PLAINS/GULF STATES THROUGH THE EXTENDED PERIOD
AND WILL ACT AS A FOCUS FOR WIDESPREAD PRECIPITATION... WITH
OCCASIONAL WINTER WEATHER NORTH OF THE BOUNDARY AND A LONG
DURATION RAIN ALONG AND SOUTH OF THE FRONT. BRIEF PERIODS OF
HEAVIER RAINFALL MAY BE POSSIBLE. SHORTWAVE ENERGY PASSING THROUGH
SOUTHERN CANADA AND THE NORTHERN U.S. WILL KEEP THE UPPER
MISSISSIPPI VALLEY TO THE NORTHEAST COLD AND SNOWY. NORTHWESTERLY
WINDS WILL LIKELY INDUCE LAKE ENHANCED SNOW FOR THE FAVORED
UPSLOPE REGIONS IN NEW YORK AND MAINE.


...GUIDANCE/PREDICTABILITY ASSESSMENT...

OVERALL THE DETERMINISTIC AND ENSEMBLE MEANS ARE IN STRONG
AGREEMENT THAT A LARGE SCALE CHANGE WILL OCCUR OVER THE NEXT
WEEK...ALTHOUGH DIFFERING IN REGARDS TO THE TIMING AND LOCATIONS
OF INDIVIDUAL SHORTWAVES. THE ECWMF AND THE GFS HAS CONTINUED TO
TREND FASTER WITH THE EASTWARD PROGRESSION OF THE TROUGH. THE CMC
WAS REMAINED SLOW WHICH APPEARED TO BE AN OUTLIER. GUIDANCE BEGAN
AS A BLEND OF THE 00Z ECWMF AND 06 GFS...AS THE TROUGH AMPLIFIES
THE DEGREE OF SPREAD AMONGST GUIDANCE WIDENED AS WELL. FOR
CHRISTMAS EVE AND CHRISTMAS THE BLEND HAD A HEAVIER WEIGHTING OF
THE 06Z ENSEMBLE MEAN AND LESSER WEIGHTING OF THE EC/GFS.

...WEATHER HIGHLIGHTS/THREATS...

A BAND OF SNOW IS FORECAST TO TRACK FROM THE CENTRAL PLAINS TO
THE NORTHEAST AS A LOW PRESSURE PASSING THROUGH. THE HIGHEST
ACCUMULATIONS ARE FAVORING THE UPPER MISSISSIPPI VALLEY/UPPER
GREAT LAKES. SNOW WILL ALSO BE POSSIBLE OVER NEW ENGLAND FRI/SAT
WHERE WARM ADVECTION WILL BE THE LIKELY MECHANISM. THERE REMAINS
SOME SPREAD OVER EXACTLY HOW STRONG THIS SYSTEM WILL BE, AND THUS
FOR PRECISE INTENSITY OF SNOW/WINDS.

THE AREA EXTENDING FROM FROM LOWER MS/TN VALLEYS INTO THE SOUTHERN
APPALACHIANS HAS THE HIGHEST PROBABILITY OF SEEING THE HEAVIEST
RAINFALL DURING THE MEDIUM RANGE. THIS WILL BE FROM A COMBINATION
OF THE COLD FRONT CROSSING THE REGION LATER IN THE WEEK, AND THEN
WITH OVERRUNNING PRECIP NORTH OF THE FRONT THAT SHOULD SETTLE NEAR
THE GULF/CAROLINA COASTS BY THE WEEKEND.

THE CENTRAL U.S. WILL HAVE A SIGNIFICANT DROP IN TEMPERATURES
LATER IN THE WEEK. A VAST AREA WILL HAVE MAXIMUM TEMPERATURES
FALLING FROM 10-20 DEG F ABOVE NORMAL TO 20-30 DEG F BELOW NORMAL
BY NEXT WEEKEND. RELATIVE WARMTH OVER THE EAST WITH SOME ANOMALIES
EXCEEDING +10 DEG F SHOULD EXTEND THROUGH SAT BEFORE BEGINNING TO
FADE BY SUN-MON WITH FRONTAL PASSAGE.

CAMPBELL

[MontgomeryCoWx]

Man, the models have gone schizo.

12z reverts back to a fetch of moisture over Texas and snow in Brownsville on Christmas Day

I'm sure that will happen.

[snowman65]

Our local mets have it 64 Christmas morning.....Yes, that's the LOW...64.....

[MontgomeryCoWx]

Our local mets have it 64 Christmas morning.....Yes, that's the LOW...64.....

I’d lay money down that your low that day will be AT LEAST 20 degrees colder than that. Your local Mets must have hugged one model run

[snowman65]

Our local mets have it 64 Christmas morning.....Yes, that's the LOW...64.....

I’d lay money down that your low that day will be AT LEAST 20 degrees colder than that. Your local Mets must have hugged one model run

I just checked all 3 locals...1 has low of 40 and high 55 and the other 2 both have low of 64, with high of 75. We'll see...probably be somewhere in the middle.

[MontgomeryCoWx]

Our local mets have it 64 Christmas morning.....Yes, that's the LOW...64.....

I’d lay money down that your low that day will be AT LEAST 20 degrees colder than that. Your local Mets must have hugged one model run

I just checked all 3 locals...1 has low of 40 and high 55 and the other 2 both have low of 64, with high of 75. We'll see...probably be somewhere in the middle.

I see low 30s to upper 40s