Upcoming cold for the South (Models, Maps, Discussions)

[Extremeweatherguy]

Indeed this will have to be watched... Keep in mind unlike the GFS "Fantasy" snow storms that are 300 hrs + this is only 6-8 days out. With colder temps than forecast now and a system "sneaking" it's way under the ridge while the cold air is in place COULD call for some Small opportunities of a possibly wintry mix. By looking at the latest GFS this is the way I see it now, of course being 6+ days away will have to see. But my forcast calls for highs Saturday to reach no higher than the mid forty's areawide. and lows in the middle to upper 20's as far south as downtown & low to mid 30's along the coast. And periods of light rain showers doing the day. And Saturday night things could get interesting as the cold air filters in the light rain showers MAY change to light snow flurries mixed in with sleet pellets & maybe even some light freezing rain as the moisture tappers off. Next Sunday may even be colder then Saturday: RIGHT NOW I'm calling for highs on Sunday to not reach the mid forty's along & north of I-10 to get into the mid forty's along the coast. and lows in the low to mid 20's areawide and of course along the coast it'll be slightly warmer with temps in the upper 20's to mid thirty's (28F-35F). Looks like early next week could also get interesting but I wont make any comments on that yet until theres more model consincy. Note: Keep in mind this is my forcast right now I could be a little to high on the temps I'll change and update my forcast when necessary.

I think this is a great forecast. I agree with it completely right now, and yes...like you said...it is still 6 days out, so changes may have to be made. Saturday night (exactly 6 days away) will certaintly be interesting. IF all the perameters are in place, then the wintry mix looks like it would be very likely...but at this time...accumulations look like they would be light at best...may be a glazing of ice on bridges and overpasses with a glaze of ice on plants, and then may be a thin trace of snow on car hoods, mailboxes and roofs...and that's IF this verifies. The worst case scenario would probably be an inch or two of snow...but since moisture looks to be limited; I would doubt we see an event like that. Anyways, can't wait to see what the models do over the next few days..and I HOPE we get some winter weather out of this event.

[Tyler]

Indeed this will have to be watched... Keep in mind unlike the GFS "Fantasy" snow storms that are 300 hrs + this is only 6-8 days out. With colder temps than forecast now and a system "sneaking" it's way under the ridge while the cold air is in place COULD call for some Small opportunities of a possibly wintry mix. By looking at the latest GFS this is the way I see it now, of course being 6+ days away will have to see. But my forcast calls for highs Saturday to reach no higher than the mid forty's areawide. and lows in the middle to upper 20's as far south as downtown & low to mid 30's along the coast. And periods of light rain showers doing the day. And Saturday night things could get interesting as the cold air filters in the light rain showers MAY change to light snow flurries mixed in with sleet pellets & maybe even some light freezing rain as the moisture tappers off. Next Sunday may even be colder then Saturday: RIGHT NOW I'm calling for highs on Sunday to not reach the mid forty's along & north of I-10 to get into the mid forty's along the coast. and lows in the low to mid 20's areawide and of course along the coast it'll be slightly warmer with temps in the upper 20's to mid thirty's (28F-35F). Looks like early next week could also get interesting but I wont make any comments on that yet until theres more model consincy. Note: Keep in mind this is my forcast right now I could be a little to high on the temps I'll change and update my forcast when necessary.

Nice forecast Don! Next weekend certainly looks interesting. Winter is going to return.

[Tyler]

UH-OH!

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _132.shtml

[Tyler]

What we have here folks on the 0z GFS is a cold 1045MB high at 132, widespread precip over Texas, and 0c 850 temps on our doorstep, and much colder air RUSHING in.

Yet another GFS flip-flop, though matches a bit more with the Euro, as far as 850 temps go..

[Tyler]

COLD COLD COLD, 850MB temps -6 to -8C across the Houston area:

[Extremeweatherguy]

BRRRR!!! Sat/Sun will probably be as cold or colder than the cold snap we got during early December. If these latest runs play out...I would expect at least one day to feature a high below 40. Also...if we can get good radiational cooling...teens are possible. We are now only talking 5-6 days away too...this is beginning to look more and more likely. Winter precip. continues to look more and more likely too. Can't wait (for the possible winter weather that is.)!

[Tyler]

BRRRR!!! Sat/Sun will probably be as cold or colder than the cold snap we got during early December. If these latest runs play out...I would expect at least one day to feature a high below 40. Also...if we can get good radiational cooling...teens are possible. We are now only talking 5-6 days away too...this is beginning to look more and more likely. Winter precip. continues to look more and more likely too. Can't wait (for the possible winter weather that is.)!

Hey EWG, take a look at this!:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_132l.gif

Now take a look at the exteneded. More bitterly cold air where that came from?

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _180.shtml

[Extremeweatherguy]

BRRRR!!! Sat/Sun will probably be as cold or colder than the cold snap we got during early December. If these latest runs play out...I would expect at least one day to feature a high below 40. Also...if we can get good radiational cooling...teens are possible. We are now only talking 5-6 days away too...this is beginning to look more and more likely. Winter precip. continues to look more and more likely too. Can't wait (for the possible winter weather that is.)!

Hey EWG, take a look at this!:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_132l.gif

this is the most hopeful look of winter weather coming to Houston that I have seen in a period closer than day 7 all this winter. Though this does not show the 0C 850mb temp. line to Houston...that does not mean that surface temps. will not be 32F (which would support frz. rain). Also, during the end of the precip. it DOES bring the 0C line to us which may allow the precip. to end as snow! I hope this verifies!

[Tyler]

BRRRR!!! Sat/Sun will probably be as cold or colder than the cold snap we got during early December. If these latest runs play out...I would expect at least one day to feature a high below 40. Also...if we can get good radiational cooling...teens are possible. We are now only talking 5-6 days away too...this is beginning to look more and more likely. Winter precip. continues to look more and more likely too. Can't wait (for the possible winter weather that is.)!

Hey EWG, take a look at this!:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_132l.gif

this is the most hopeful look of winter weather coming to Houston that I have seen in a period closer than day 7 all this winter. Though this does not show the 0C 850mb temp. line to Houston...that does not mean that surface temps. will not be 32F (which would support frz. rain). Also, during the end of the precip. it DOES bring the 0C line to us which may allow the precip. to end as snow! I hope this verifies!

Very good points. IMO, its too close for comfort! And, it will change!

Plus, there is more cold air where that came from, 180 hour:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _180.shtml

[Tyler]

Okay, here is how I see the 0z GFS:

0z GFS, hour 120:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _120.shtml

Important features to note right there. First, the PNA ridge appears very strong, shooting up into Canada and Alaska. However, there appears to be a disturbance cutting into it. That may weaken it a bit, so thats something to watch, and could determine how much south the cold air will flow.

Second, the high pressure is dictated as a 1045MB high over Montana, diving south, bringing with it very cold air. The strength of this high will also determine how far south, and how cold we get.

Third, check out that disturbance in the southwest, moving east toward our area. The 0z GFS keeps this quite strong, and develops widespread precip over the area at 132. Will the rushing arctic air arrive at the same time the disturbance is over the area, and possibly produce wintry precip!? I don't know, its possible, but I would like to hear a pro's opinion on this.

The variables above will determine exactly how cold it gets, if we have precip fall, and what kind of precip that will be.

0z GFS hour 132:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _132.shtml

0z GFS 132 Precip and 850MB temps:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_132l.gif

Notice the 0c line is very close to Houston. Wow! This is getting interesting. We better stay tuned during the next couple of days, you never know what might just happen.

[Tyler]

It must be noted that the 0z GFS MOS temp guidance has come way down for next week, and next weekend. I still believe it is too warm past 120 hour. I would expect highs next weekend to be stuck possibly in the 30's, considering this airmass is colder than last December...

http://www.srh.noaa.gov/data/Guidance/G ... KIAH.1.txt

Here is what that says:

Tommorow's high: 65
Tuesday: lo 33 hi 66
Wednesday: lo 36 hi 69
Thursday: lo 42 hi 58
Friday: lo 38 hi 65
Saturday: lo 43 hi 56 (too warm)
Sunday: lo 31 hi 54 (too warm)
Monday: lo 35 hi 63 (too warm)

I suspect the GFS continues to have trouble with this arctic airmass, BUT, its nice that its finally trying to come around.

I'm dying to hear what the NWS here in Houston has to say about this...

[cctxhurricanewatcher]

It should be very interesting what the overnight AFD's say about those models you guys posted. Do I sense a "Bears Watch" coming from the Houston NWS soon?

[Tyler]

It should be very interesting what the overnight AFD's say about those models you guys posted. Do I sense a "Bears Watch" coming from the Houston NWS soon?

Maybe!

[LAwxrgal]

COLD COLD COLD, 850MB temps -6 to -8C across the Houston area:

WOA...looking at that map, we're going to shiver here too! And there are plenty folks living in tents and FEMA trailers...especially east of me...

[wxman22]

Latest GFS run has some pretty COLD temps in the area. One thing I want to note though is last 0z run of the GFS was warm bias now the new 0z is more cold bias, with the 0z being the best model run of the GFS this could get pretty intresting.... Can't wait to see the 12z runs!! Note: The European model also cuts off a low to the west of us Friday. (Like Dan said on KHOU's weather forum this could be a wild card in the forcast this weekend) We'll just have to see...

[Brent]

COLD COLD COLD, 850MB temps -6 to -8C across the Houston area:

http://monkeynetwork.com/model/gfsday72.gif

That makes you cold looking at it.

[LarryWx]

Very light snow started here a little north of the ATL perimeter right at 3:40 AM with a temp of 35.4 F. This is MUCH earlier than models expected!

[Tyler]

Good luck on the snow Larry!

[Tyler]

Dallas NWS AFD tried to hint of winter precip next weekend:

THE UPPER LEVEL PATTERN WILL CHANGE VERY LITTLE THROUGH THE WEEK
WITH A LARGE RIDGE IN THE WEST AND A LONG WAVE TROUGH IN THE EAST.
THIS PATTERN WILL ALLOW SEVERAL SURGES OF COLD AIR TO MOVE THROUGH THE
PLAINS AND ACROSS TEXAS. THE COLD FRONT EXPECTED WEDNESDAY
AFTERNOON WILL COME THROUGH DRY. HOWEVER...ANOTHER COLD FRONT
EXPECTED FRIDAY AFTERNOON MAY HAVE A LITTLE MORE MOISTURE TO WORK
WITH...ESPECIALLY IN THE SOUTH WHERE SOME OVERRUNNING IS EXPECTED.
TEMPERATURES FRIDAY NIGHT WILL BE FALLING BEHIND THE FRONT AND
SHOULD REACH THE LOWER AND MIDDLE 30S BY SUNRISE SATURDAY. FOR NOW
WILL LEAVE ONLY SHOWERS MENTIONED AS CLOUD COVER SHOULD KEEP TEMPS
ABOVE FREEZING WHERE IT IS PRECIPITATING...BUT WILL HAVE TO KEEP
A CLOSE EYE ON THE SYSTEM IN THE COMING DAYS.

MUCH DRIER AND COLDER AIR IS IN STORE FOR NORTH TEXAS SATURDAY AND
SUNDAY WITH HIGHS IN THE 40S AND LOWER 50S AND LOWS SATURDAY NIGHT
REACHING INTO THE 20S TO LOWER 30S.

[wxman22]

Heres the latest discussion from the NWS in Houston(Intresing)....:.DISCUSSION...
COLD FRONT HAS ENTERED OUR NW ZONES AND IS MOVING SOUTHEAST AT AROUND
25 KNOTS. FRONT WILL REACH THE COAST BETWEEN 12Z AND 13Z THIS
MORNING. STRATUS DECK IS FILLING IN QUICKLY ACROSS CWA...AND PER ETA
FCST SOUNDINGS WILL LIKELY PERSIST FOR AT LEAST A COUPLE OF HOURS
FOLLOWING FRONTAL PASSAGE. HOWEVER...SKIES SHOULD CLEAR QUICKLY MOST
AREAS BY MID MORNING AT THE LATEST. ALTHOUGH AN ISOLATED -SHRA IS
STILL POSSIBLE OVER OUR EASTERN ZONES BEFORE FROPA...WILL OPT TO JUST
HANDLE THIS IN NOWCASTS AND NOT MENTION PRECIP IN THE FORECAST.
NORTH WINDS WILL INCREASE TO 15 TO 25 MPH BY THIS AFTN RESULTING IN
FIRE WEATHER CONCERNS (SEE BELOW). HIGH PRESSURE SETTLES OVERHEAD
TONIGHT SETTING UP OPTIMAL RADIATIONAL COOLING CONDITIONS. A LIGHT
FREEZE IS POSSIBLE IN SOME OF THE RURAL AREAS OF SE TX.

500 MB PATTERN WILL UNDERGO AMPLIFICATION THIS WEEK WITH A STRONG
RIDGE DEVELOPING ALONG THE WEST COAST INTO WESTERN CANADA AND A DEEP
TROUGH DEVELOPING IN THE GREAT LAKES REGION. THIS WILL ALLOW SEVERAL
SURGES OF COLDER AIR TO DROP SOUTH INTO THE MIDDLE OF THE COUNTRY
OVER THE NEXT SEVERAL DAYS. THE 00Z GFS IS FINALLY COMING INTO BETTER
AGREEMENT WITH THE ECMWF WHICH HAS BEEN ON BOARD WITH THIS PATTERN
CHANGE FOR SEVERAL DAYS NOW. THE FIRST FRONT IS DUE IN LATE WED
NIGHT/THURSDAY MORNING AND EVEN THIS FRONT HAS ITS ORIGINS IN NORTHERN
CANADA. LOWERED TEMPS THURSDAY CLOSER TO THE MEXMOS GUIDANCE. THE
SECOND AND STRONGER FRONT IS EXPECTED TO CROSS SE TX LATE FRIDAY
(ECMWF) TO EARLY SATURDAY (GFS). AS THIS FRONT REACHES SE TX...A SLOW
MOVING SOUTHERN STREAM UPPER LOW IS FORECAST TO SHEAR OUT OVER SE
TX...ENHANCING LIFT IN ASSOCIATION WITH FRONT. LATEST GFS RUN HAS PWS
INCREASING TO 1.3-1.4 INCHES FRIDAY NIGHT WITH BOTH GFS/ECMWF SHOWING
SATURATED AIRMASS OVER SE TX. HAVE INCREASED POPS TO LOW CHANCE
CATEGORY BUT MAY NEED TO GO HIGHER IF MODELS CONTINUE THIS TREND.

BOTH MODELS SHOW VERY STRONG COLD ADVECTION IN THE WAKE OF THE EARLY
WEEKEND FRONT WITH 850 MB TEMPS FALLING TO -4 TO -8C OVER SE TX BY
12Z SUNDAY. GIVEN FORECAST CLOUD COVER AND STRONG COLD ADVECTION WENT
BELOW GUIDANCE FOR MAX TEMPS SATURDAY. FREEZING TEMPS LOOK LIKE A
GOOD BET FOR MOST INLAND AREAS SATURDAY NIGHT AND POSSIBLY AGAIN