January: Increasing Clouds/Rain & Warmer To End Month

[MontgomeryCoWx]

Any moisture associated with those Lows tracking across south Texas?

[wxman57]

Looks like the GFS is forecasting highs in the 40s next Friday but with high pressure overhead then moving off to the east on Saturday. Could be a light freeze next Fri/Sat.

I notice the 12Z GFS builds a pool of very cold surface air (30-40F below normal) all across western Canada between the 15th-18th. However, the GFS keeps that cold air in Canada before eroding it and replacing it with warmer than normal temps at day 15 (by the 21st). Have to keep an eye on that cold air (if it develops). Though the GFS isn't forecasting it to make an appearance in Texas yet, if it's in Canada then we at least have a chance of some significant cold after the 15th.

[srainhoutx]

Also of note, the 12Z Canadian is much slower (12-24 hours) with the upper low early next week suggesting the heavier rains/storms will hold off until Monday afternoon/night. I tend to agree that a slower solution than the GFS is showing is more likely and if the Euro also shows that slower movement, it would seem to be more plausible with the current upper air pattern, IMO.

[srainhoutx]

We'll need to keep an eye on a slower/colder depiction of the Canadian. If the profiles look the same and the Euro leads the way, I still wouldn't rule out a stray sleet pellet or two if the trends continue as the U/L passes near us...

[srainhoutx]

And again, the Canadian agrees with a strong front and colder temps as a potent Winter Storm winds up in the Great Lakes/Ohio Valley for next weekend...

[MontgomeryCoWx]

That gives me hope.

[srainhoutx]

The #2 scoring at 500mb UKMet suggests a slower progression of the upper low across Texas early next week...

HPC Diagnostics Discussion prior to the Euro output:

5/12Z MODEL EVALUATION INCLUDING THE 12Z CANADIAN/UKMET

...UPPER TROUGH/CUTOFF ENERGY MOVING INTO PAC NW/GREAT BASIN...D2-3

PREFERENCE: NON-12Z NAM COMPROMISE

OVERALL...THE 12Z NAM SPINS UP AND GENERATES ITS H5 SHORTWAVE A
LITTLE FASTER THAN THE OTHER GUIDANCE OVER ERN OREGON AND CARRIES
THAT ENERGY AND ITS MOMENTUM EWD...ALMOST PHASED WITH NORTHERN
PORTION OF THE TROUGH. TRENDS WITH THE 12Z GFS/UKMET/CANADIAN FROM
THEIR MOST RECENT RUNS...SAY OTHERWISE. RECOMMEND FOLLOWING A 00Z
ECMWF AND 00Z EC MEAN APPROACH...CLOSING IT OFF INVOF THE SOUTHERN
GREAT BASIN AND DESERT SOUTHWEST. EVERYTHING ELSE TO THIS
POINT...SUPPORTING A CLOSED SYSTEM AT H5. A COMPROMISE SOLUTION
USING THE GFS/UKMET IMPLIES A SLIGHTLY FASTER EJECTION OF SOME OF
THE ENERGY EWD INTO THE SOUTHERN PLAINS...BUT PRESERVES THE CLOSED
CIRCULATION AND HANGS A GOOD PORTION OF THE ENERGY AND VORTICITY
BACK ACROSS THE FOUR CORNERS BY THE END OF DAY 3.

[srainhoutx]

The 12Z Euro suggests a slower progression of the upper low across Texas and remains very wet. That model also hints at some wintry mischief for New Mexico and W Texas as the upper low slowly treks across the region.

01052012 12Z Euro f96.gif

01052012 12Z Euro f120.gif

01052012 12Z Euro f144.gif

[srainhoutx]

Although the Euro is slower with the development of the Winter Storm depicted on the Canadian, it does suggest a full latitude trough and phasing of the northern and southern streams and drops very chilly air S into the Plains and Texas.

[wxman57]

12Z Euro is 3-5 hours faster than the GFS with the movement of the upper low across SE TX next Tuesday. Neither indicates anything but rain. Canadian is another 6 hrs or so slower than the Euro and does indicate at least some precip in the cold air. Probably too warm aloft for anything but cold rain, but can't 100% absolutely rule out the chance of a single sleet pellet.

Both Euro and GFS indicate a freeze across most of Harris County next Friday, and possibly a very light freeze next Saturday.

[srainhoutx]

Allan's site has updated through hour 168 on the 12Z Euro. Impressive phasing to say the least...

[wxman57]

That's what I'm seeing, srain. 12Z Euro has 850mb temps about 8-10C below normal across Houston next Friday, or down to right about freezing (0C) briefly. That's supportive of a freeze next Friday. Temps aloft warm significantly aloft after then, though.

Here's a meteogram based upon the 12Z GFS. As you can see, it has our temps quite a bit above freezing during the rain next week. It also looks like it may not be a bad biking weekend.

[srainhoutx]

The HPC surface progs are out for next week and they paint an interesting picture. The qpf forecasts are suggesting a potential 3+ inches of rain beginning Sunday into Tuesday. The surface charts do suggest a modified Arctic boundary pushing through Thursday finally clearing us out and setting the stage for a very chilly late week into next weekend. We will see...

[MontgomeryCoWx]

3 inches of rain would be heavenly. If we can trend above normal in Jan/Feb like December, Spring will take care of itsself.

[srainhoutx]

HGX is agreeing with the heavy rainfall potential and even mentioning heavy thunderstorms. What is note worthy is past experience suggests bouts of heavy rains with thunder are often followed by a significant cool down that happen in January and that is exactly what guidance is suggesting. Stay Tuned. Next week looks rather changeable...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
325 PM CST THU JAN 5 2012

.DISCUSSION...
STATIONARY FRONT OVER THE AREA IS VERY DIFFUSE AT 21Z GENERALLY
ALONG THE I-10 CORRIDOR BUT NOT A WEATHER FOCUS. OF MORE
IMPORTANCE IS THE UPPER LOW OVER MEXICO THAT WILL CONTINUE TO MOVE
EAST AND INCREASING SOUTHERLY FLOW SHOULD DRAW MOISTURE NORTH INTO
SETX TONIGHT AND FRIDAY WITH A FEW SHOWERS ALONG THE COAST AND
INTO THE COASTAL COUNTIES BUT LIGHT ACCUMULATIONS AT BEST. PATCHY
FOG WILL BE POSSIBLE AGAIN OVER THE SOUTHERN ZONES. ANOTHER COLD
FRONT WILL MOVE SOUTH THROUGH THE DALLAS AREA AROUND 06Z SATURDAY
AND EVENTUALLY INTO THE NW COUNTIES OF SETX SATURDAY THEN STALL. A
WET PATTERN WILL TAKE SHAPE WITH THE STALLED BOUNDARY A SLOW
MOVING UPPER TROUGH TO THE WEST AND INCREASED SOUTHERLY FLOW.
SUNDAY THE CLOUDS SHOULD QUICKLY INCREASE BECOMING MOSTLY CLOUDY
TO CLOUDY AND CONTINUED WELL ABOVE NORMAL TEMPERATURES. RAINS
SHOULD START IN THE NORTH AND SPREAD SOUTH AS THE FLOW ALOFT
BECOMES MORE FAVORABLE. MODELS ARE OUTPUTTING SIGNIFICANT
ACCUMULATIONS DURING THE EVENT STARTING SUNDAY NIGHT THROUGH
TUESDAY. SOME DIFFERENCES WITH A SLOWER ECMWF BUT STILL LOOKS LIKE
A HIGH CONFIDENCE RAIN EVENT FOR SETX. INSTABILITY ON MONDAY
SHOULD SUPPORT RAIN WITH EMBEDDED SHOWERS AND THUNDERSTORMS.
WOULDN`T EVEN RULE OUT SOME HEAVY SHOWERS AND THUNDERSTORMS.
PACIFIC COLD FRONT SHOULD SWEEP OUT THE MOISTURE TUESDAY WITH WRAP
AROUND CLOUDS AND A FEW SHOWERS BENEATH THE COLD CORE. FOLLOWED
ECMWF TEMPERATURES CLOSELY IN THE EXTENDED TUESDAY AND BEYOND.

[Ptarmigan]

That's what I'm seeing, srain. 12Z Euro has 850mb temps about 8-10C below normal across Houston next Friday, or down to right about freezing (0C) briefly. That's supportive of a freeze next Friday. Temps aloft warm significantly aloft after then, though.

Here's a meteogram based upon the 12Z GFS. As you can see, it has our temps quite a bit above freezing during the rain next week. It also looks like it may not be a bad biking weekend.

Looks like the heaviest rain is on Sunday night to early Monday morning. I wonder if there will be thunderstorms. January rarely has thunderstorms, but they do happen.

[srainhoutx]

Guidance is coming together suggesting a very active period beginning on Sunday. There are some hints of severe storms with gusty winds and small hail possible as a potent upper low slowly organizes in Northern Mexico and a stalled frontal boundary meanders near Central/SE Texas and a Coastal Low develops near the Lower/Middle Texas Coast. Rain and showers look to increase beginning from W to E on Sunday as the slow moving 5H low organizes and deepens near or just S of the Big Bend Region. While the exact track remains uncertain and this disturbance is now closing in on the Pacific NW, indications do suggest a stormy period is ahead.

This feature will enter the RAOB network Friday into Saturday as it moves onshore and drops SSE into the Great Basin/4 Corners Area. Winter Storm conditions may be expexted in New Mexico Saturday night into Sunday. The early QPF forecasts suggest 2-3 inches of rain, mainly E of the I-35 corridor with isolated 4+ inch amounts possible just N of the Houston Metro area. Training of storms may be possible and Flash Flood criteria may be met.

As the closed cold core upper low treks E, cold air aloft could bring elevated storms with small hail as the upper levels will be very unstable. There are some indictions a trowal like feature will develop N of the U/L, and depending on track and profiles, wintry mischief may be possible. As the storm system passes, a strong push of cold Canadian air looks to be tapped as yet another Winter Storm winds up along the northern stream near the Great Lakes/Upper Mid West. A strong front appears likley Wednesday night into Thursday morning. Light snow may develop across the Southern Plains as this boundary dives S. Stay tuned as we appear to be heading into a very active period!

[srainhoutx]

The 06Z GFS offers some wintry mischief in the longer range for Central and SE Texas, for what it's worth...

[Katdaddy]

Small area of showers and thunderstorms just offshore of Matagorda County headed NNE toward the Upper Texas Coast.

[srainhoutx]

SPC morning Update:

...MIDDLE/UPPER TX COAST INTO LOWER MS VALLEY...

A CLUSTER OF ELEVATED TSTMS HAS PERSISTED THIS MORNING JUST OFF THE
MIDDLE TX COAST WITHIN A ZONE OF FORCING FOR ASCENT AHEAD OF
ABOVE-MENTIONED MID- TO UPPER-LEVEL LOW. THE 12Z LCH SOUNDING
APPEARS TO BEST CAPTURE THE RETURN OF A MODIFIED CP AIR MASS
INLAND...YIELDING MUCAPE OF AROUND 1000 J/KG. THIS INSTABILITY WILL
LIKELY CONTINUE TO SUPPORT SPORADIC LIGHTNING ACTIVITY INVOF OF THE
UPPER TX AND SWRN LA COASTS INTO EARLY AFTERNOON. THEREAFTER...
WEAKENING FORCING FOR ASCENT AND THE PRESENCE OF A WARM NOSE
CENTERED AROUND 750 MB /EVIDENT IN FORECAST SOUNDINGS/ CAST
UNCERTAINTY ON TSTM POTENTIAL FARTHER E AND INLAND OVER SRN PARTS OF
LA AND MS LATER TODAY INTO TONIGHT.