December 2017: End Of The Year Weather

[sau27]

??? 2013? We haven't had highs in the 20s since 89 I don't think. Looking at the 2013 record, no such cold stands out.

The longest run of below freezing max temps at both Bush and Hobby is 4 days (2/4/89 - 2/7/89 & 12/23/83 - 12/26/83)

[MontgomeryCoWx]

I’m fairly positive we had 2 straight days of sub freezing highs in 2013 around one of our 6 winter weather events that winter.

I know we had a high in the 20s in February 2011 and trying to remember if 2008/2009 had one as well. I’ll do my research tonight.

I do realize I am speaking about my location in Montgomery county and not IAH, so that may Be where we are differing.

[srainhoutx]

The 18Z GEFS suggests a very impressive Omega Block to our NW tapping into some chilly Siberian Air. That's one heck of a longwave trough across Central North America and temperatures (in Celsius) look mighty chilly compared to what we have experienced the last couple of Christmas's.

[TexasMetBlake]

Guys, I'm looking at the 2013 records at IAH and no such cold exist. No temperatures are below freezing for highs be there in January, February or December 2013 -- much less highs in the 20s.

[MontgomeryCoWx]

Guys, I'm looking at the 2013 records at IAH and no such cold exist. No temperatures are below freezing for highs be there in January, February or December 2013 -- much less highs in the 20s.

Yeah, in my last sentence I said my lens is based on my location in MoCo and not IAH.

Wasn’t 2013/2014 the crazy winter with all the mini ice events or was it 2012/2013?

[Ptarmigan]

Guys, I'm looking at the 2013 records at IAH and no such cold exist. No temperatures are below freezing for highs be there in January, February or December 2013 -- much less highs in the 20s.

Yeah, in my last sentence I said my lens is based on my location in MoCo and not IAH.

Wasn’t 2013/2014 the crazy winter with all the mini ice events or was it 2012/2013?

It was 2013-2014. The Gulf Of Alaska was very warm that time. It is favorable for ridging over Alaska, which is negative East Pacific Oscillation (EPO).

[MontgomeryCoWx]

Guys, I'm looking at the 2013 records at IAH and no such cold exist. No temperatures are below freezing for highs be there in January, February or December 2013 -- much less highs in the 20s.

Yeah, in my last sentence I said my lens is based on my location in MoCo and not IAH.

Wasn’t 2013/2014 the crazy winter with all the mini ice events or was it 2012/2013?

It was 2013-2014. The Gulf Of Alaska was very warm that time. It is favorable for ridging over Alaska, which is negative East Pacific Oscillation (EPO).

That was Nuri-gate Winter.

[Ptarmigan]

??? 2013? We haven't had highs in the 20s since 89 I don't think. Looking at the 2013 record, no such cold stands out.

The last time there was highs of 20s was on December 23, 1989. It happened twice in 1989, the other being on February 4, 1989.

http://www.weather.gov/hgx/climate_iah_normals_feb
http://www.weather.gov/hgx/climate_iah_normals_dec

??? 2013? We haven't had highs in the 20s since 89 I don't think. Looking at the 2013 record, no such cold stands out.

The longest run of below freezing max temps at both Bush and Hobby is 4 days (2/4/89 - 2/7/89 & 12/23/83 - 12/26/83)

The longest below freezing temperature was in 1951. It lasted for 5 days or 123 hours!

http://www.wxresearch.com/almanac/frezhour.htm

[Ptarmigan]

Yeah, in my last sentence I said my lens is based on my location in MoCo and not IAH.

Wasn’t 2013/2014 the crazy winter with all the mini ice events or was it 2012/2013?

It was 2013-2014. The Gulf Of Alaska was very warm that time. It is favorable for ridging over Alaska, which is negative East Pacific Oscillation (EPO).

That was Nuri-gate Winter.

That was in November 2014.

[Ptarmigan]

The 18z guys is so out of the ordinary and several standard deviations below normal that it almost doesn't even make sense. I would be very cautious when throwing around numbers that the 18z GFS is throwing out.

Showing highs in the mid 20s all day Tuesday (day after Christmas) and upper 20s to near 30 all day Wednesday. That hasn't happened in decades. Let's just wait and see.

I am trying to remember the last time we spent the better part of 48 hours below freezing. I seem to remember an ice storm from when I was a kid, maybe in the 1994-1995 time frame, where it stayed that cold for that long long time.

There was a freeze and freezing rain in January 1997. It was below freezing for 2 days. There was also a freeze in February 1994, snow and ice storm.

[MontgomeryCoWx]

My official high on 2/4/11 was 28 degrees.

My highs from 2/6/14 to 2/8/14 were 30, 30 and 31.

That’s where my head was at when referencing 20 something highs.

And my God we must have had a record number of freezing temps that 13/14 Winter. I counted double digits just in january alone. If I go back and count I believe February had double digits too. That was also the winter we received a freezing rain event the first week in March.

[Ptarmigan]

When Houston Saw Highs That Were In The 20s
January 1, 1928
January 10, 1962
January 12, 1892
January 18, 1930
January 19, 1940
January 20, 1978
January 22, 1930
January 30, 1949
January 30, 1951
January 31, 1951
February 1, 1951
February 2, 1951
February 1, 1985
February 4, 1989
February 7, 1895
February 8, 1933
February 9, 1929
February 13, 1899
February 14, 1895
December 20, 1924
December 23, 1989
December 24, 1983
December 25, 1983

This is from 1889 to 2017. I suspect there that the highs did not go above 20s in the 1820-1821, 1845-1846, 1852, 1873, 1875, January 1886, and January 1888 Freeze. The high in Galveston on January 8, 1886 was 31°F and on January 16, 1888 was 32°F.

It is a rare occurrence. 23 have occurred in Houston from 1889 to 2017. On average that should be every 5.6 years. The last happening on December 23, 1989.

The lowest high was on February 13, 1899, with a high of 20°F! The latest date to see 20s as a high was on February 14, 1895, which was during the epic snow event.

Got It From Here
http://threadex.rcc-acis.org

[MontgomeryCoWx]

Bookmarked that link... will use that for a few other locations. Wish they had KCXO on there.

[don]

I wonder if the models are bringing back the winter storm? Both the GFS and Canadian have a winter storm across the state after Christmas.The GFS is the most aggressive though fwiw...

[stormlover]

The models suck right now!!! Will keep changing

[Andrew]

Anything beyond Christmas has extremely low confidence. Models are going back and forth with how much reinforcement cold air comes down. The GFS in particular shows a noisy jet creating the winter storm posted above but it showed a similar setup last week for this weekend (and we know how that changed). I suspect a similar result will occur again. Cold and dry. One thing is looking more and more likely and that is a cold Christmas. Some models continue to be rather aggressive with the second front on the 24th. Could see freezing temps Christmas morning, but either way it will be a welcoming change from the last couple years where Christmas was well above average.

[Katdaddy]

A Dense Fog Advisory for all of SE TX this morning with showers and a few thunderstorms moving into SE TX. The SPC has shifted the marginal risk area N of the coastal area overnight. After showers and thunderstorms today and tonight; expect mostly sunny skies and mid to upper 70s across SE TX tomorrow.

[snowman65]

Time to roll the dice and see what the models feel like telling us today....I have my handy magic 8 ball just in case

[srainhoutx]

Looking at the current temperatures across our source Regions of the NW Territories and Yukon in Canada, I am finally seeing some -20C to near -40C temperatures in some locations. Now let's see if some of that cold Canadian Air can head South in the days ahead. Meanwhile, careful when out and about today into this evening. Rounds of rain, some possibly heavy with thunderstorms this afternoon into evening look likely.

Get out and enjoy tomorrow if you can. That will likely be the best weather day we see in some time...

[srainhoutx]

I edited the Topic Title to drop that mention of Ice for now...(sorry wxman57). Confidence is increasing for an Artic Intrusion into our Region for Christmas, but that high confidence stops with the finer details regarding any moisture over running the shallow Artic Air beyond the 23rd to 25th. The strongest High Pressure I see in the WPC surface charts is 1044 which seems reasonable at this time. As always, we'll continue to monitor just in case a curveball or two pop up in the Day 2 to 3 range.

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
127 AM EST TUE DEC 19 2017

VALID 12Z FRI DEC 22 2017 - 12Z TUE DEC 26 2017

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


...OVERVIEW...

CONFIDENCE REMAINS HIGH FOR A MAJOR PATTERN CHANGE ACROSS NORTH
AMERICA OVER THE NEXT SEVERAL DAYS. A SPLIT FLOW PATTERN VERY
EARLY IN THE PERIOD WILL QUICKLY UNDERGO A SIGNIFICANT
AMPLIFICATION, WITH AN EASTERN PACIFIC RIDGE AXIS EXTENDING FROM
JUST OFF THE U.S. WEST COAST NORTH TO THE ARCTIC, AND A DOWNSTREAM
MEAN TROUGH FROM NEAR HUDSON BAY SOUTHWEST INTO THE CONUS. THIS
SETUP WILL RESULT IN A FLOW OF AIR FROM THE HIGH LATITUDES OF THE
ARCTIC SOUTHWARD THROUGH CANADA AND INTO THE
PLAINS/MIDWEST/ROCKIES. TELECONNECTIONS ASSOCIATED WITH THE AREA
OF MAXIMUM POSITIVE HEIGHT ANOMALIES ACROSS NORTHWEST CANADA (+2
TO +3 STANDARD DEVIATIONS ON THE GEFS MEAN) SUPPORT THE IDEA SHOWN
BY MOST GUIDANCE, WITH THE NORTHERN/CENTRAL PLAINS AND UPPER
MIDWEST THE FAVORED AREAS FOR THE COLDEST TEMPERATURES BY THE
WEEKEND. FARTHER EAST, THE SUBTROPICAL RIDGE IS FORECAST TO
STRENGTHEN, CENTERED OVER THE BAHAMAS OR SOUTH FLORIDA (ALSO
SUPPORTED BY TELECONNECTIONS TO THE NORTH PACIFIC RIDGE). THE
CONTRAST BETWEEN THE FLOW OF ARCTIC AIR SOUTHWARD INTO THE CENTRAL
U.S. AND WARM, MOIST SUBTROPICAL AIR TRANSPORTED NORTHWARD INTO
THE SOUTHERN/SOUTHEASTERN U.S. WILL SUPPORT A PERSISTENT AND SHARP
FRONTAL ZONE FROM THE GULF OF MEXICO NORTHEASTWARD INTO THE
SOUTHEAST AND JUST OFF THE MID-ATLANTIC COASTLINE. SOME
UNCERTAINTY REMAINS REGARDING EXACTLY WHERE THIS FRONTAL ZONE SETS
UP (DISCUSSED MORE BELOW), WHICH WILL HAVE MAJOR IMPLICATIONS FOR
THE WEATHER ACROSS THE EASTERN U.S. BY THE WEEKEND. EXPECT THIS
FRONT TO SERVE AS A FOCUS FOR POTENTIAL ROUNDS OF PRECIPITATION,
WITH SOME POTENTIAL FOR WINTER WEATHER ON THE NORTHERN FRINGES
GIVEN THE SHARP THERMAL GRADIENT. ADDITIONALLY, MODELS SUGGEST THE
POTENTIAL FOR A WAVE OF LOW PRESSURE TO DEVELOP ALONG THE FRONT BY
SUN-MON ALONG THE SOUTHEAST/MID-ATLANTIC COAST.


...GUIDANCE/PREDICTABILITY ASSESSMENT...

DURING DAYS 3-5, MODELS SHOW SOME TIMING DIFFERENCES WITH RESPECT
TO THE SHORTWAVE AND ASSOCIATED SURFACE LOW MOVING FROM THE
CENTRAL PLAINS TO THE GREAT LAKES AND INTO SOUTHEAST CANADA. IN
GENERAL, A 12Z ECMWF/12Z GFS BLEND, WITH SMALL COMPONENTS OF THE
RESPECTIVE ENSEMBLE MEANS INCLUDED, WAS THE PREFERRED APPROACH
DURING THIS TIME PERIOD. MEANWHILE, CONFIDENCE IS HIGH THAT A
LARGE POSITIVELY-TILTED TROUGH WILL BEGIN TO AMPLIFY ACROSS THE
CENTRAL U.S. BY SAT AS A SHORTWAVE CROSSES THE ROCKIES AND
AMPLIFIES. MEANWHILE, A DEEP UPPER LOW INITIALLY NEAR HUDSON BAY
WILL DRIFT SOUTHWARD TOWARD THE UPPER MIDWEST.

UNCERTAINTY BEGINS TO INCREASE AFTER SUN WITH RESPECT TO HOW
QUICKLY HEIGHTS WILL FALL ACROSS THE EASTERN U.S. THE ECMWF HAS
BEEN CONSISTENT IN KEEPING A STRONGER SUBTROPICAL RIDGE IN PLACE,
WHICH DELAYS THE ARRIVAL OF THE COLD FRONT INTO THE EASTERN U.S.,
WHILE THE GFS AND CMC PUSH THE FRONT THROUGH MOST OF THE EASTERN
U.S. BY SUN, BEFORE STALLING IT TEMPORARILY FROM THE NORTHERN GULF
OF MEXICO TO THE CAROLINAS. THIS SCENARIO SEEMS TO BE FAVORED TO
SOME DEGREE BY BOTH THE GEFS AND ECENS MEANS, BOTH OF WHICH
SUGGEST THE LOWEST PRESSURES SUN-MON WILL BE LOCATED ALONG AN AREA
GENERALLY ALONG THE EAST/SOUTHEAST U.S. COAST. THUS, WHILE THE
ECMWF SCENARIO CANNOT BE RULED OUT, AM NOT FAVORING THE SLOWER
FRONTAL PROGRESSION AT THIS TIME. TO FURTHER COMPLICATE MATTERS,
THE GFS HAS SHOWN A LARGE DEGREE OF RUN-TO-RUN VARIABILITY, WITH
THE 18Z RUN IN PARTICULAR BRINGING THE CORE OF THE ARCTIC AIR
EASTWARD TOWARD THE CENTRAL APPALACHIANS BY TUE. THIS SCENARIO WAS
ALSO NOT PREFERRED AT THIS TIME. TELECONNECTIONS WOULD SUPPORT
SOME MODEST MAINTENANCE OF THE SUBTROPICAL RIDGE WITH THE CORE OF
THE COLD AIR DIRECTED SOUTHWARD ACROSS THE CENTRAL U.S., AT LEAST
INITIALLY. THUS, GIVEN THE UNCERTAINTY AMONG THE GUIDANCE, THE
FORECAST FOR DAYS 6-7 WAS BASED LARGELY ON A BLEND OF THE 12Z
ECENS/GEFS MEANS, WITH ONLY SMALL COMPONENTS OF THEIR RESPECTIVE
DETERMINISTIC SOLUTIONS INCLUDED. WHILE THIS SCENARIO DOES BRING
THE ARCTIC FRONT INTO THE EASTERN U.S. BY TUE, THE CORE OF THE
COLD AIR WOULD REMAIN DIRECTED INTO THE CENTRAL U.S. GIVEN THE
POSITION OF THE SURFACE HIGH ACROSS THE NORTHERN HIGH PLAINS.


...WEATHER HIGHLIGHTS/THREATS...

THE SURFACE LOW TRACKING ACROSS THE GREAT LAKES FRI-SAT WILL BE
ACCOMPANIED BY A BAND OF SNOW ON THE NORTH SIDE OF THE SYSTEM.
SNOW WILL ALSO BE POSSIBLE OVER NEW ENGLAND FRI/SAT WHERE WARM
ADVECTION WILL BE THE LIKELY MECHANISM. THE AREA EXTENDING FROM
FROM LOWER MS/TN VALLEYS INTO THE SOUTHERN APPALACHIANS HAS THE
HIGHEST PROBABILITY OF SEEING HEAVY RAINFALL DURING THE MEDIUM
RANGE. MODELS SHOW A GROWING CONSENSUS FOR AN AREA OF VERY
HEAVY/EXCESSIVE RAINFALL POTENTIAL FRI-SAT ACROSS THIS AREA IN
ASSOCIATION WITH A SLOW-MOVING FRONT WHICH IS FORECAST TO
EVENTUALLY STALL OVER THE SOUTHEAST BY SUN. ADDITIONAL OVERRUNNING
PRECIPITATION WILL BE POSSIBLE NORTH OF THE STALLED FRONT ON
SUNDAY, PERHAPS LOCATED A BIT TO THE SOUTHEAST OF THE FRI-SAT
HEAVY RAINFALL AREA, ALTHOUGH CONFIDENCE IN THE EXACT FRONTAL
PLACEMENT REMAINS A BIT BELOW AVERAGE FOR THE REASONS DESCRIBED
ABOVE. IF A FRONTAL WAVE DEVELOPS ALONG THE SOUTHEAST/MID-ATLANTIC
COASTLINE AS FORECAST BY SUN-MON, THIS WOULD SPREAD AN ORGANIZED
ROUND OF PRECIP ACROSS AREAS FROM THE CAROLINAS NORTHWARD,
ALTHOUGH AT THIS TIME THERMAL FIELDS ARE TOO UNCERTAIN TO
SPECULATE MUCH ON RAIN/SNOW AREAS. NONETHELESS, SOME POTENTIAL FOR
WINTER WEATHER WOULD EXIST, ESPECIALLY FOR THE APPALACHIANS AND
INTERIOR MID-ATLANTIC/NORTHEAST IN THIS SCENARIO. IF THE CURRENT
FORECAST WERE TO VERIFY, THIS WOULD LIKELY MEAN A COLD RAIN FOR
THE MAJOR CITIES ALONG THE I-95 CORRIDOR GIVEN THAT THE ARCTIC
FRONT WOULD STILL BE TO THE WEST OF THE REGION AND NO OBVIOUS
SOURCE OF LOW-LEVEL COLD AIR IS EVIDENT. THIS FORECAST IS STILL
SUBJECT TO SIGNIFICANT CHANGES, HOWEVER, GIVEN THE DESCRIBED
UNCERTAINTY.

TEMPERATURES ACROSS THE CENTRAL U.S. WILL BE ON THE DECLINE
THROUGHOUT THE MEDIUM RANGE AS A COUPLE ARCTIC FRONTAL BOUNDARIES
IN QUICK SUCCESSION SPREAD INCREASINGLY COLD AIR SOUTHWARD. THE
COLDEST TEMP ANOMALIES WILL INITIALLY BE JUST EAST OF THE ROCKIES
SAT-SUN, WITH HIGH TEMPS 15 TO 30 DEG F BELOW AVERAGE. BY MON-TUE,
THE COLDEST ANOMALIES, ALSO 15 TO 30 DEG F BELOW AVERAGE, WILL
SHIFT TO THE NORTHERN PLAINS AND UPPER MIDWEST, WHERE HIGH
TEMPERATURES FOR SOME AREAS WILL REMAIN BELOW ZERO, AND LOWS MAY
REACH -20 DEG F. MEANWHILE, ABOVE AVERAGE TEMPS WILL PERSIST
ACROSS THE EASTERN U.S. UNTIL THE FIRST COLD FRONT IS ABLE TO
PASS. HIGH TEMPS FRI-SAT ARE FORECAST TO 10-20 DEG F ABOVE AVERAGE
FOR THE SOUTHEAST, OH VALLEY, AND MID-ATLANTIC.

RYAN