January: Seasonal Temps To End The Month

[Portastorm]

As I mentioned on another forum, the GFS has really struggled though with how to handle southern stream energy in this pattern. It's waffled a bit in the last few runs. Looks to be keeping that central Plains low quite strong while ignoring what, if anything, happens at the base of the western US trough.

I'm going to be curious to see how the CMC and Euro look in a few hours.

[Andrew]

As I mentioned on another forum, the GFS has really struggled though with how to handle southern stream energy in this pattern. It's waffled a bit in the last few runs. Looks to be keeping that central Plains low quite strong while ignoring what, if anything, happens at the base of the western US trough.

I'm going to be curious to see how the CMC and Euro look in a few hours.

Well all models have really been doing a poor job at handling the Jet and how noisy it has been. Srain and I were talking about that. The Euro even showed a very dry atmosphere today throughout central Texas but we had precip across the area. That will be something to watch as we get into the short range.

[srainhoutx]

Another thing to monitor is the very deep convection that has developed off Mexican Pacific Coast near the Mexican Rivera. The sub tropical jet is becoming very noisy and I'm not so sure the frontal boundary will make a big push off shore of Coastal Texas. There could be some training heavy rains developing tomorrow night into New Years Day. All the guidance is struggling with numerous features be it out W in Northern Mexico, the active SJT as well as short waves diving S to SE from the Pacific NW. This will be a very complex and complicated forecast for the next week, in my humble opinion.

[Andrew]

Another thing to monitor is the very deep convection that has developed off Mexican Pacific Coast near the Mexican Rivera. The sub tropical jet is becoming very noisy and I'm not so sure the frontal boundary will make a big push off shore of Coastal Texas. There could be some training heavy rains developing tomorrow night into New Years Day. All the guidance is struggling with numerous features be it out W in Northern Mexico, the active SJT as well as short waves diving S to SE from the Pacific NW. This will be a very complex and complicated forecast for the next week, in my humble opinion.

For the amount of precipitable water in a deep layer in the atmosphere, I'd almost expect the models to be showing more rain totals.

Probably due to the lack of instability whatever rain does develop will be on the lighter side. That will probably limit totals.

[Ptarmigan]

Another thing to monitor is the very deep convection that has developed off Mexican Pacific Coast near the Mexican Rivera. The sub tropical jet is becoming very noisy and I'm not so sure the frontal boundary will make a big push off shore of Coastal Texas. There could be some training heavy rains developing tomorrow night into New Years Day. All the guidance is struggling with numerous features be it out W in Northern Mexico, the active SJT as well as short waves diving S to SE from the Pacific NW. This will be a very complex and complicated forecast for the next week, in my humble opinion.

Just saw satellite image looks almost like a tropical system.

[Andrew]

CMC is coming in wetter and stronger:

[srainhoutx]

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
131 AM EST MON DEC 31 2012


PRELIM DAY 1 QPF DISCUSSION
VALID DEC 31/1200 UTC THRU JAN 01/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR



DAY 1...

...SOUTHERN ROCKIES EASTWARD INTO THE SOUTHERN/CENTRAL PLAINS AND
LOWER-MID MS AND OH VALLEYS...

THE LATEST MODEL RUNS REMAIN IN GOOD AGREEMENT THROUGH DAY 1 WITH
THEIR HANDLING OF THE BROADER SCALE TROUGH MOVING OUT OF THE
SOUTHWESTERN U.S. INTO THE CENTRAL AND SOUTHERN PLAINS. AN
INITIAL BURST OF SNOW OVER THE CO/NM ROCKIES OCCURS IN AN AREA OF
700 MB CONVERGENCE NEAR THE LOW LEVEL CIRCULATION CENTER.
THIS ACTIVITY TAPERS AS THE LOW MOVES INTO THE HIGH PLAINS. A
BAND OF ENHANCED 850 MB CONVERGENCE SET UP ACROSS OK-KS-NORTH
TX...WITH THE NORTHERN END MOVING EAST MORE QUICKLY THAN THE
SOUTHERN END LINGERING OVER TX. REFER TO HPC WINTER WEATHER
PRODUCTS FOR DETAILS CONCERNING HEAVY SNOW THREATS ACROSS KS/MO.

A STRONG SOUTHWEST-NORTHEAST 500-300 MB JET WITH BANDS OF UPPER
DIVERGENCE HELP TRIGGER ASCENT AHEAD OF A DEVELOPING COLD FRONT IN
THE LOWER MS VALLEY. MODELS SHOW THE RAPID RETURN OF GULF MOISTURE
AHEAD OF THE EJECTING TROUGH WITH PWS INCREASING TO 1.5-1.75
INCHES OR MORE ACROSS EASTERN TX/LA. IN ADDITION TO INCREASING
MOISTURE...850-700 MB MOISTURE FLUX ANOMALIES FEED INCREASING
RAINFALL AMOUNTS.

MANUAL QPF USED A MULTI-MODEL BLEND...WHICH IS HIGHER THAN THE 12Z
ECMWF DUE TO MULTIPLE FACTORS FAVORABLE FOR CONVECTION PLUS THE
TRADITIONAL ECMWF LOW BIAS IN HIGH MOISTURE ENVIRONMENTS. THE
PRIMARY DIFFERENCE BETWEEN THE MODEL CONSENSUS AND MANUAL QPF IS I
NUDGED THE AXIS A LITTLE FURTHER SOUTHEAST INTO SOUTHEAST TX/LA
ENDING 12Z TUE AS THE GFS SHOWS THE PEAK 850-700 MB
CONVERGENCE/HIGHEST PW VALUES/HIGHEST MOISTURE FLUX VALUES EAST OF
THE QPF AXIS.

PETERSEN

[srainhoutx]

I know a lot of attention has been focused on the over running event that some of the guidance have been suggesting for Wednesday into Thursday. The 03Z SREF Ensemble mean does advertise a ‘wet pattern’ at virtually all levels of the atmosphere as the next in a series of short waves drop S and round the base of the Great Basin trough. While temps and freezing levels appear to be borderline at best and surface temps are forecast to be marginal or above freezing, I would not be surprised to see a mixed bag of precip develop to our W across W Central Texas and slowly migrate E as over running develops along a wavy quasi stationary frontal boundary along Coastal Texas/Louisiana. The best chance of snow appears to be across El Paso, Southern New Mexico and the Big Bend Region into near Midland. There are some individual members (more than one or two) that suggest a bit closer to Kerrville/San Antonio down to Eagle Pass/Laredo areas could see a mix of rain/sleet/snow. For Austin and the Houston area, perhaps our most likely precip would be a very chilly rain with a sleet pellet or two with Austin and College Station down to Brenham and over to Huntsville and Lake Livingston having a better chance of seeing any sleet mixing in with the cold rain. That said this is still a developing complex and complicated weather situation as a cold front will push S into Texas Wednesday as a rather strong short wave dives SE from Wyoming/Colorado riding over a ridge of high pressure developing across the Great Basin and another short wave rounds the base of a rather deep trough axis extending back to our W across Northern Mexico. A very noisy sub tropical jet just adds to the forecast difficulties as deep convection continues to fire off shore of Mexico in the Eastern Pacific.



SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
357 AM EST MON DEC 31 2012

VALID 12Z MON DEC 31 2012 - 12Z WED JAN 02 2013

...SNOW IS EXPECTED FROM THE CENTRAL/SOUTHERN ROCKIES EASTWARD
INTO SECTIONS OF THE UPPER OHIO VALLEY...

...THE COLDEST WEATHER REMAINS OVER THE NORTH-CENTRAL CONUS...


AN UPPER TROUGH EJECTING OUT OF NORTHERN MEXICO WILL GRADUALLY
LIFT NORTHEASTWARD ABOVE A SUBTROPICAL RIDGE ANCHORING THE
SOUTHEASTERN U.S. THE AMPLITUDE OF THIS TROUGH AXIS WILL DIMINISH
IN TIME AS IT FEELS THE EFFECTS OF THIS EXPANSIVE RIDGE TO ITS
SOUTH. BEFORE THIS OCCURS...THE MID-LEVEL ENERGY STREAMING OUT OF
SOUTHERN ARIZONA/NEW MEXICO WILL BE ACCOMPANIED BY AN ACTIVE
SUBTROPICAL PLUME OF MOISTURE RISING FROM DEEP IN THE EASTERN
PACIFIC. THIS WILL CONTINUE TO ALLOW PRECIPITATION TO BREAK OUT
NORTH OF A SURFACE BOUNDARY SPRAWLED ALONG THE WESTERN GULF COAST.
THE AIR MASS ON THE NORTHERN FRINGE OF THIS SHIELD OF
PRECIPITATION IS FORECAST TO REMAIN COLD ENOUGH TO SUPPORT SNOW.
THE BEST THREAT FOR ACCUMULATIONS APPEARS TO BE ACROSS KANSAS
WHICH IS WHERE THE BEST MOISTURE TRANSPORT AND STRONGEST UPPER
DYNAMICS WITH THE TROUGH WILL BE IN PLACE. THE HPC WINTER WEATHER
FORECAST SUGGESTS A WIDESPREAD 4 TO 6 INCHES OF SNOW WILL BE
POSSIBLE DURING THE NEXT 24 HOURS WITH POCKETS OF HEAVIER AMOUNTS
ACROSS CENTRAL KANSAS. AS THE SYSTEM BEGINS TO WEAKEN ON ITS SHIFT
EASTWARD...THE LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY WILL ALSO
DIMINISH LEADING TO LOWER SNOWFALL AMOUNTS FROM ILLINOIS OFF
TOWARD OHIO. LOOKING FARTHER SOUTH...SHOWERS AND THUNDERSTORMS
SHOULD BECOME NUMEROUS OVER THE DEEP SOUTH...PARTICULARLY ALONG
THE COLD FRONT.

A SERIES OF WEAK IMPULSES TRACKING THROUGH THE GREAT LAKES WILL
KEEP CONDITIONS CHILLY OVER THE NORTHEASTERN U.S. TO ENTER THE
YEAR 2013. AS THE MID-LEVEL FORCING WITH THESE DISTURBANCES WILL
BE RATHER WEAK...ONLY MINOR SNOWFALL ACCUMULATIONS ARE EXPECTED
DOWNWIND OF THE MAJOR GREAT LAKES.

THE ARCTIC AIR REMAINS TRAPPED INTO THE HIGHER LATITUDES OF CANADA
THEREBY KEEPING TEMPERATURES RATHER MODERATED OVER THE NATION.
WHILE NEW YEARS EVE OVERNIGHT TEMPERATURES DROPPING INTO THE -10
TO -15 DEGREE RANGE IS NOT UNHEARD OF GIVEN THE TIME OF YEAR...THE
UPPER MIDWEST DOES MARK THE COLD SPOT IN THE COUNTRY. A WARMING
TREND IS ACTUALLY IN STORE FOR THIS REGION BY NEW YEARS DAY AS A
WARM FRONT CROSSES THE NORTHERN TIER STATES. THIS WILL ULTIMATELY
RAISE TEMPERATURES FROM NEAR 0 DEGREES TO THE LOWER TEENS FOR
TUESDAY ACROSS THE UPPER MIDWEST WITH LOWER 20S BACK TOWARD THE
NORTHERN HIGH PLAINS.


RUBIN-OSTER

[kennethb]

Just to give an idea of what type of winter we are having so far here in south Louisiana, yesterday morning we had our coldest morning yet here in Baton Rouge of 28. I have a couple tropical sages, cassia, milkweed, that have yet to freeze back. Yes they have been nipped, but only slightly. Even this morning, I realized the poinsettias I planted this past spring have not frozen back and in fact are just beginning to bloom. Even the mild winter last year, I had the plants above frozen back by Christmas. I would expect that by February we will have the killing freeze, but that remains to be determined by the PNA, AO, NAO, SOI, La Nina, El Nino, Taco Bell etc.

[srainhoutx]

Morning update from Jeff:

Widespread rainfall will develop this evening and continuing into Tuesday.

Warm front with all its associated weather (fog, drizzle, and light rain) currently extends from near Victoria to Wharton to San Luis Pass. South of the front temperatures have increased to 71 at Bay City versus 48 at Caldwell. Fog and drizzle are noted across nearly the entire area. Warm front will make very slow northward progress today possibly reaching I-10 by late afternoon while increasing upper level lift from a short wave ejecting out of the mean SW US trough moves into the region this afternoon. Expect to see widespread light to moderate rainfall develop with a few heavier showers. Could see a thunderstorm or two near the warm front this afternoon as the lift increases, but the chance is fairly low given near zero instability.

Main event is expected tonight as another strong cold front sags into the area. Moisture profiles on the CRP and BRO 12Z soundings were in the 1.3-1.5 inch range on the PWS and expect this moisture advection to progress up the coast and into SE TX this afternoon. This does support heavy rainfall given the high moisture parameters for this time of year, but lack of any significant surface instability should greatly reduce the threat for organized thunderstorms producing very heavy rains.

General widespread rainfall with embedded heavy downpours can be expected tonight with storm totals of 1-2 inches NE of a line from Brenham to Angleton with isolated totals near 3 inches. SW of this line totals will average .5 to 1 inch.

Temperature today will slowly rise to the mid to upper 60’s south of the warm front and remain steady of slowly rise into the mid 50’s north of the boundary. Cold front tonight will knock temperatures back into the 40’s and they will remain in the 40’s on Tuesday under gusty NW winds, clouds, and lingering rainfall.

Cold front will slowly sag off the coast on Tuesday with drier low level air mass filtering southward. Large swath of rainfall should progress to the coast and possibly offshore, but active southern stream jet in combination with main axis of the upper level trough remaining west of the area over N MX will continue thick clouds and potential rain chances Wed-Thurs. Models are not and have not been handling the mid-late week pattern/forecast very well as they bounce between wet and dry. One item that is nearly certain is that temperatures will be cool to cold with lows in the 40’s and highs in the 50’s under mainly cloudy skies. As for rainfall, will keep some chance of rainfall near the coast, but it is uncertain as to how far inland rains may spread from time to time as weak disturbances translate through the SW US trough and across TX. Wed night and Thurs AM look like a possible wet period especially near the coast.

[srainhoutx]

The 16Z HRRR is rather suggestive of elevated storms and training rainfall developing after midnight into the early morning hours of New Years Day.

[Portastorm]

It still appears like a minor winter weather event could occur for places like Del Rio, Ozona, Sonora, stretching into western sections of San Antonio and maybe even the active natural gas/fracking areas of south Texas (i.e. Cotulla). The 12z GFS is coming in and shows enough precip and cold enough 850mb temps that perhaps some sleet or even a few snowflakes might fall late Thursday into early Friday. The SREF ensemble means also show this happening.

For most of us, that's probably west or south of our locales. Who knows ... maybe they'll be a few surprises for some of us.

[srainhoutx]

Just emptied a half inch of rain out of the old rain bucket from the overnight moderate rain that fell in NW Harris County. I see areas from Down Town on SE did much better in the rainfall department with nearly 4 inches in Galveston. Not too shabby... It does a appear the sub tropical jet will remain rather noisy, so don't expect much in the way of clearing skies before that 500mb vort/trough starts to shift E from Northern Mexico later this week into the weekend. Notice the closed core low dropping S in California along with a short wave dropping SE in Wyoming/Colorado with yet a stronger short wave up stream in British Columbia heading SE.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1012 AM CST TUE JAN 1 2013

.DISCUSSION...
HEAVIER PRECIP HAS SHIFTED OFFSHORE AND IS ALONG THE COLD FRONT
OVER THE COASTAL WATERS OUT BEYOND 20NM. THE FRONT SHOULD CONTINUE
TO MOVE SOUTHEAST THOUGH SLOWLY. PATCHY LIGHT RAIN WILL CONTINUE
THIS MORNING MAINLY OVER THE SOUTHERN HALF OF THE AREA INTO THE
EARLY AFTERNOON. AS LIFT WITH APPROACHING SHORTWAVE OVER THE HILL
COUNTRY NEARS EXPECT THE PRECIP TO SHIFT EAST AND LIGHTEN.
OVERCAST SKIES WILL PREVAIL THROUGH THE AFTERNOON HOURS BUT MAY
BECOME BROKEN THIS EVENING IN THE NORTHWESTERN AREAS WITH MAINLY
HIGH CLOUDS. THE LIGHT PRECIP AND COLD AIR ADVECTION SHOULD KEEP
TEMPERATURES IN THE MID 40S TO MID 50S WITH NEAR STEADY
TEMPERATURES. WILL LIKELY DO AN UPDATE AROUND 1130 OR NOON TO
CLEAR OUT PRECIP IN THE WEST AND NORTHWEST.

AS OF 1005 AM THIS MORNING GALVESTON HAS HAD A RECORD SETTING 3.99"
OF RAIN AND IS STILL FALLING THOUGH LIGHTER NOW.

[Ptarmigan]

Another thing to monitor is the very deep convection that has developed off Mexican Pacific Coast near the Mexican Rivera. The sub tropical jet is becoming very noisy and I'm not so sure the frontal boundary will make a big push off shore of Coastal Texas. There could be some training heavy rains developing tomorrow night into New Years Day. All the guidance is struggling with numerous features be it out W in Northern Mexico, the active SJT as well as short waves diving S to SE from the Pacific NW. This will be a very complex and complicated forecast for the next week, in my humble opinion.

For the amount of precipitable water in a deep layer in the atmosphere, I'd almost expect the models to be showing more rain totals.

Probably due to the lack of instability whatever rain does develop will be on the lighter side. That will probably limit totals.

There has to be lift like a upper level low.

Highest PW value for Southeast Texas in January is 2.00 inches. A PW value above 1.60 is +2 above standard deviation.

http://www.crh.noaa.gov/unr/?n=pw-gridded#

[Ptarmigan]

For future reference, handy PW climatology chart by date for various radiosonde launch locations.

http://www.crh.noaa.gov/unr/?n=pw

I looked at Top 50 PW for Lake Charles (KLCH).
http://www.crh.noaa.gov/images/unr/soo/pw/pw_Top50.pdf

Here is what I found. None are in the winter and spring. They are in summer and fall.

Month
June 3
July 14
August 18
September 12
October 3

Hour
0000Z 22
0600Z 1
1200Z 26
1800Z 1

Highest PW By Month
June 2.63 June 30, 2010 6Z
July 2.77 July 11, 1963 0Z
August 2.80 August 18, 2010 12Z
September 2.70 September 12, 1998 0Z
October 2.77 October 3, 1995 12Z

Interesting to note that many of the flood events do not make it in the top 50 PW for Lake Charles. It would be interesting to see PW for Houston.

[srainhoutx]

Looking ahead to next week, the GFS and Euro are suggesting a fairly potent storm system crossing Southern Arizona/Southern New Mexico next Tuesday/Wednesday. What raises an eyebrow is the fact that we may have moderating temps beyond this weekend and if the medium/long range guidance is correct, a severe episode may be ahead before another rather sharp cold snap following that storm system. Something to monitor in the days ahead…

[jasons2k]

I just got home and found .48" in the rain bucket. I can't tell when what fell when, so I'll split the difference and record .24" for 12/31 and start the year with .24".

That gives me a December total of 1.02" and a total for 2012 of 37.62".

[srainhoutx]

There were some 'hints' via the 00Z NAM (4km WRF), 21Z SREF mean and even the GFS that there may be a potential for wintry mischief Thursday/Friday for areas of West and Central Texas extending as far S as Laredo into San Antonio and possibly even as close as the NW Austin suburbs. The shorter range guidance is suggesting a bit more moisture at all levels and a stronger 500mb vort crossing near or just S of the Big Bend Region finally phasing with the trough that lingers into Northern Mexico. There are some indications that some light precip will extend as far E as the Northern half of SE TX as well. We'll continue to monitor this potential as there will be a re enforcing shot of cold air arriving Thursday ahead of the trough finally beginning to head ENE Friday into Saturday.

[Belmer]

Saw this on another website:

"With the PNA going back to negative and the NAO going negative, we are going into a two-week warming pattern starting this weekend. Looking at the long-range models, it would seem that the cold will once again come back the last week of January into February.
While we have a good snow cover across the country east of the Rockies, we are probably going to lose a lot of the snow cover over the next two weeks.
I am having trouble trying to find any significant snow event for the next two weeks. The GFS suggests that we may have big storm in the Plains around the 12th, but given the ups and downs of the models lately, I am not relying on that just yet.
So for now, it's January thaw weather coming for a couple of weeks before winter sets back in."

Makes sense for the most part.

[Belmer]

06Z GFS is probably getting some mouths watering. Looking a lot better. Hope the trend can continue. Houston may hopefully be in for a few surprises when all set and done.