February-Comfortable Days/Cool Nights To The Month

[srainhoutx]

The 12Z suite of operational and ensemble guidance continues to advertise an unsettled zonal split flow throughout the week with a couple of short waves moving across the Region. One weak disturbance is crossing the area near SE OK/NE TX area today with a bit stronger wave moving S of Arizona at this hour across Northern Mexico and should spark off additional showers and isolated storms Wednesday. The next short wave appears a bit stronger and with a boundary oscillating across Central Texas, a better chance of rainfall is looking likely.

Looking ahead to the weekend, the guidance is fair agreement that a long wave trough and attending 500mb storm develops near the CA/AZ/MX border. Embedded short waves are depicted to drop SE toward the base of a SW to NE or positive tilted trough axis that will extent from the Baja Region of NW Mexico on NE to the Great Lakes/Mid West. The ensembles are still suggesting a cut off upper low will linger into Monday suggesting showers and storms, some possibly severe will develop across W Central Texas Saturday and very slowly transition E into Monday, should the cut off solution verify. Winter Storm RECON has been tasked and is scheduled to make 13 drops across the NE Pacific to sample the environment beginning February 6th at 00Z.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0100 PM EST MON 04 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
VALID 05/1100Z TO 06/1100Z FEBRUARY 2013
WSPOD NUMBER.....12-066

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. FLIGHT ONE -- NOAA 49
A. P56/ DROP 7 (44.3N 151.0W)/ 06/0000Z
B. NOAA9 07WSC TRACK56
C. 05/1900Z
D. 13 DROPS ON TRACK NORTH OF 37.0N WITH SPACING
BETWEEN DROP POINTS SET AT APPROXIMATELY 90 NM.
E. 41,000 TO 45,000 FT/ 06/0600Z

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

[srainhoutx]

Oh, and for those wondering about that 'chilly air' that has been mentioned mid month, here is the latest for IAH...enjoy it while it lasts...

[harpman]

srain, can you interpret the above? Thanks.

[srainhoutx]

srain, can you interpret the above? Thanks.

The GFS is suggesting a low near 25 with some light wintry mischief before drying out near the 18th-19th. Oh course we can't trust the models beyond 5 days if even then, but the Climate Prediction Center update today did put all of the Western 2/3rd of the US in below normal temps and above average precip from E Central TX on E into Louisiana. We will see.

[Ptarmigan]

I looked at past weather records and noticed thunder was recorded during the January 30, 1949 freeze and snow event in Houston. College Station went below zero.

http://www.ncdc.noaa.gov/most-popular-data

Go to Individual Station Original, which is Original COOP forms (PDF).

[harpman]

Thank you. I saw the 12Z run of the GFS. Interesting to say the least.

[srainhoutx]

The next short wave disturbance appears to be very vigorous and has abundant moisture and some instability to work with. Heavy rainfall and even some strong to possibly severe storms with training heavy rain is not out of the question for Wednesday into early Thursday across much of the Southern half of Texas into Louisiana. PW's have increased to the 1.5+ range and the HPC is suggesting QPF may approach the 2-3+ inch mark for portions of the Rio Grande Valley into S Central/SE Texas as well as Louisiana. We may get close to Flood Advisory Criteria if the trends continue today as this short wave is tracking further S across Old Mexico and a boundary is draped over or just N of the Hill Country.

[srainhoutx]

Morning e-mail from Jeff:

Fairly active WSW to SW flow aloft will bring a few chances of rainfall to the region this week in an overall unsettled pattern.

Patchy dense fog across portions of the area is lifting into more of a low deck of stratus clouds, except near the coast and in the bays where thicker sea fog is currently in place. Will continue to deal with the threat for periods of dense sea fog along the coast for the next 24 hours as fairly light to moderate winds combined with warm moist air flowing over the cooler nearshore waters promotes fog development. SE TX will be in between systems today with only a few scattered showers possible mainly E of I-45 and south of I-10.

Attention will focus on the Wednesday afternoon and overnight period as a fairly strong short wave trough in the SW flow aloft moves out of Mexico and into SW and then SC TX on Wednesday and Wednesday afternoon. Low level moisture is already increased over the area in response to a weak short wave passage yesterday afternoon which was able to squeeze out a few fast moving showers. This next incoming system appears more well defined and stronger in the model guidance with both the global and shorter term meso models showing a fair amount of upstream thunderstorms development on Wednesday late morning into the early afternoon over the Rio Grande plains into SC TX and then spreading ESE into the coastal bend and SE TX during the afternoon and into the overnight hours. While the low level flow backs to the ESE enhancing the low level shear late Wednesday, the amount of available instability appears to be lacking for a significant severe weather threat. Additionally clouds will hamper early day heating and forecast soundings only show a small amount of instability through the air column. For now, this looks like an isolated severe weather threat mainly south of I-10, but any modest heating on Wednesday could result in SPC upgrading parts of the area into a slight risk.

Of greater importance is the threat for heavy rainfall mainly over the southern ½ of the region Wednesday-Wednesday night. Short term meso models are suggestive of a couple of bands of training convection over SE TX during this period as the lift from the short wave combines with the southerly low level jet and copious Gulf moisture. Moisture levels will be high with PWS of 1.5 inches but not excessive. Meso models are attempting to develop activity along some sort of boundary near the coast…could be a weak coastal front or air mass change zone due to more surface heating over S TX on Wednesday. I will follow along with the TX TECH WRF model which did well with the early Jan 2013 rainfall event and this model places at least of couple of lines of thunderstorms across the area well into Wednesday night. South of I-10 rainfall amounts of 1-2 inches will be possible with isolated amounts of 3 inches while north of I-10 amounts will generally average .5 to 1 inch. Should see rains come to an end Thursday morning…but there may be some left over showers especially near the coast early before drier air arrives from the west.

Area will be dry from Thursday afternoon-Friday ahead of a major SW US storm system that begins to approach the plains over the weekend. Moist southerly flow begins on Saturday, but minus any undetected disturbances in the upper level flow Saturday should be a fairly dry day. With moisture increasing off the Gulf, will throw in a 20% rain chance for any streamer showers on Saturday. Rain chances begin to increase Sunday-Monday as increasing lift from the large storm system spreads into the plains. Still some timing and thermodynamic uncertainties in the forecast for this system in terms of potential capping and severe weather parameters.

[srainhoutx]

Morning Updated from the HPC regarding the Medium Range. Winter RECON is still schedule to fly the NE Pacific tonight and sample the system expected to bring a weather events for the late weekend/early next week time frame originating to our West...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1015 AM EST TUE FEB 05 2013

VALID 12Z FRI FEB 08 2013 - 12Z TUE FEB 12 2013


THERE ARE TWO MAJOR SYSTEMS SLATED TO IMPACT THE CONTIGUOUS UNITED
STATES AT THE MEDIUM RANGE. THE FIRST INVOLVES SHORTWAVES
INTERACTING IN THE SPLIT FLOW OFF THE NORTHEAST COAST DAY 4. THE
MODELS HAVE CONVERGED ON THE TIMING OF THE INDIVIDUAL IMPULSES
THROUGH DAY 3, BUT HAVE NOT COME INTO AGREEMENT ON THE DEGREE TO
WHICH THE SHORTWAVES PHASE ONCE OVER THE ATLANTIC OCEAN. THE ECMWF
HAS BEEN MOST AGGRESSIVE WITH THE INTENSITY OF THE PHASED CYCLONE,
WITH THE EUROPEAN CENTRE ENSEMBLE MEMBERS ONLY MODESTLY CLUSTERING
WITH THE DETERMINISTIC VERSION. THE GFS, GEM GLOBAL, AND UKMET
SOLUTIONS HAVE PROVEN EVEN MORE SCATTERSHOT THAN THE ECENS
INDIVIDUAL MEMBERS. FOR THIS PARTICULAR FORECAST, USED AN EVEN
BLEND OF THE 00Z/05 ECMWF AND ECENS MEAN FOR THE NORTHEAST SYSTEM,
PRIMARILY BECAUSE OF THE CREEP OF THE MEAN TOWARDS THE MORE
INTENSE DETERMINISTIC SOLUTION. SINCE THE EVENT INVOLVES DISPARATE
IMPULSES FROM DIFFERENT STREAMS, THE MOST LIKELY CHANCE FOR A HIGH
IMPACT ON SENSIBLE WEATHER WOULD BE OVER EASTERNMOST NEW ENGLAND.

THE SECOND SYSTEM IS ALSO ONE OF THE "WILL THEY/WON'T THEY"
PHASING ILK. THE ENERGY WILL BE CROSSING THE WEST EARLY IN THE
PERIOD, WITH THE LION'S SHARE OF THE FLOW OVER THE SOUTHWEST. HERE
AGAIN, THE DETERMINISTIC ECMWF IS THE MOST AGGRESSIVE WITH THE
RESULTING CYCLONE, INDICATING A DEEP SURFACE LOW OVER THE UPPER
MIDWEST DAY 6. ONCE MORE, THE ECENS MEAN HAS ONLY SUBTLY WAXED
TOWARD A LARGE, CONSOLIDATED SYSTEM. THE OTHER GLOBAL
DETERMINISTIC MODELS HAVE OFFERED FEW CLUES AS TO THE POTENTIAL OF
THE EVENT. BECAUSE THIS SYSTEM IS FARTHER OUT IN TIME, AND DOES
NOT HAVE AS ROBUST OF ENSEMBLE SUPPORT AS THE NORTHEAST SYSTEM,
CHOSE TO WEIGHT THE MANUAL PROGS WITH TWO-THIRDS OF THE MOST
RECENT ECENS MEAN. ONE THING UPON WHICH THE DIFFERENT MODELS DO
AGREE WITH THIS EVENT IS THAT THE GULF OF MEXICO IS LIKELY TO BE
HEAVILY TAPPED, WITH WIDESPREAD SIGNIFICANT RAINFALL INDICATED F0R
THE DEEP SOUTH INTO THE OHIO VALLEY.


CISCO

[wxman57]

The 12Z GFS doesn't have any significant cold for Houston through the 21st, but it does indicate some significant rainfall tomorrow.

[JackCruz]

Will the rain event tomorrow be a daytime thing or evening into night? Just wondering....

[srainhoutx]

The trends today seem to suggest a positive tilted trough hanging back to the Great Basin with a couple of lows ejecting NE before the main trough and attending 500mb closed cold core low tracks E across the Region next week. The 12Z Euro certainly is suggesting such a scenario may well be possible. We will see.

[srainhoutx]

Yep. Then we wash, rinse and repeat the pattern...via the Euro...

[Ptarmigan]

Will the rain event tomorrow be a daytime thing or evening into night? Just wondering....

Looks to be more of an afternoon to night event.

[Ptarmigan]

Globals not as excited, but not a complete buzz kill either. ARW/NAM 12Z

I do not put a lot of stock in NAM model.

[wxman57]

Will the rain event tomorrow be a daytime thing or evening into night? Just wondering....

Looks like most of the rain falls in the middle of the day. Rain from mid morning to sunset or a little after.

[David Paul]

Our 'Microcast' model agrees. Rain begins in the morning, heavier stuff out west counties... then moves across se Texas taking most of the afternoon and evening. 2"-3" totals likely with this...

[srainhoutx]

HPC is increasing Winter RECON tasking for both the NW Atlantic (North East Storm threat) and the NE Pacific (Great Basin Storm threat) during the next several days.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1240 PM EST TUE 05 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
VALID 06/1100Z TO 07/1100Z FEBRUARY 2013
WSPOD NUMBER.....12-067

I. ATLANTIC REQUIREMENTS
1. FLIGHT ONE --TEAL 71--
A. A66/ DROP 7 (24.9N 93.9W)/ 07/0000Z
B. AFXXX 06WSA TRACK66
C. 06/2030Z
D. 10 DROPS ON TRACK AS PUBLISHED
E. AS HIGH AS POSSIBLE/ 07/0230Z

FLIGHT TWO --TEAL 72--
A. A66/ DROP 7 (24.9N 93.9W)/ 07/1200Z
B. AFXXX 07WSA TRACK66
C. 07/0830Z
D. 10 DROPS ON TRACK AS PUBLISHED
E. AS HIGH AS POSSIBLE/ 07/1430Z

2. OUTLOOK FOR SUCCEEDING DAY:
A. FLIGHT ONE ....A65/ DROP 6/ 08/0000Z
B. FLIGHT TWO.....A62/ DROP 6/ 08/1200Z

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK:
A. P56/ DROP 9/ 08/0000Z
3. REMARKS: TRACK P56 WILL BE FLOWN TODAY AS DETAILED
ON WSPOD 12-066.

[jeff]

Little worried that coastal convergence will set up with the heavy stuff near/just offshore. Such a pattern "robs" the inland moisture and keeps the heavy rainfall anchored near the coast.

[srainhoutx]

The 00Z 4km HIRES NAM is suggesting some near 2 inch amounts across the Middle and Upper Texas Coast. We will see.