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

[gboudx]

Tyler, in your opinion is this shifting Westward and colder a trend, or something that's just started?

[Tyler]

Tyler, in your opinion is this shifting Westward and colder a trend, or something that's just started?

Really and truley, its something that just started. If you think back to yesterday, 12z GFS had us at +1C 850 temps!! Thats as low as it would go. The high pressure was only 1036MB!

Now today, the 12z GFS may start a trend, as the high is now 1048MB, and we've got -8 to -9 C 850MB temps across the area. Needless to say, I wouldn't be suprised if 0z GFS trended even colder!

Again, NAM and GFS match up. Thats a good sign.

I'm wondering how the MOS guidance is going to handle this...

[vbhoutex]

Also, if you've noticed, not only is the high stronger every run, BUT the coldest air is shifted westward as well!

Possible that the ridge in the West is shifting W, which is what we need to get the "polar express" kind of cold we need to hit the low 20's-IOW a straight shot from AK down the East slope of the Rockies. There is a definite shift West. We need to see if it continues or if the model is just teasing us.

[Tyler]

Also, if you've noticed, not only is the high stronger every run, BUT the coldest air is shifted westward as well!

Possible that the ridge in the West is shifting W, which is what we need to get the "polar express" kind of cold we need to hit the low 20's-IOW a straight shot from AK down the East slope of the Rockies. There is a definite shift West. We need to see if it continues or if the model is just teasing us.

Correct! Tonight's 0z runs will be interesting. Last nights 0z runs were the most critical, because if the GFS didn't shift colder, than we knew something was wrong. However, the GFS DID shift colder, therefore, we now know the GFS was out to lunch yesterday, and the Euro (as well as all other global models) had this arctic intrusion pegged 7 days ago!

[Tyler]

Also of note, a MAJOR northeastern US snow storm has popped up out of nowhere at 84 hours... The system was offshore, looks like now it could hug the coast, those of you living in the northeast may be in for a suprise!

[Tyler]

12z GFS MOS guidance again not handling this well AT ALL. High temps saturday about 8 degrees to warm, and low 30's saturday night are not going to happen... With the GFS now trending colder, I'd expect highs to be stuck in the 40's saturday, with lows in the mid 20's saturday night. Lows monday morning also WAY too warm. Lower 40s!? LOL, lets go with mid 30s monday morning, this cold airmass is not going to moderate THAT fast. Overall, a COLD weekend lies ahead.

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

Wxman57, a professional meteorologist, had this to say about it over on the KHOU message boards:

"Besides being colder, the 12Z GFS also keeps the clouds in here longer on Saturday. With such strong cold air advection, we may be looking at a high in the mid 40s. The temperature could be hanging around 40-42 by noon Saturday. I don't see any precip once teh cold air thickens, though. Cold and dry."

[Johnny]

As with the last arctic air that came down last December...places in southeast, Texas might get a surprise flurry or two with this one. You won't see it in the forecast though.

[Tyler]

I don't know about that, looks like moisture will be gone by the time the coldest air moves in. But, ya never know...

[jdray]

http://www.srh.noaa.gov/ifps/MapClick.p ... 5&map.y=63

NWS Jax is starting to see some colder air.
28/29 for Saturday Night & Sunday Night.

[Johnny]

I don't know about that, looks like moisture will be gone by the time the coldest air moves in.

That's what the NWS said about the moisture with the last arctic air that moved down this past December. My father in law who works right on the shoulder of I-45N in Willis had a 25 to 30 minute snow shower. While he was getting these flurries I checked the radar and didn't see a thing. Their were alot of other reports also coming from The Woodlands area, Cleveland and up in my neck of the woods up towards Conroe. Personally I didn't see any but apparently alot of other people saw some flurries. Like you said, you never know.

[Tyler]

I don't know about that, looks like moisture will be gone by the time the coldest air moves in.

That's what the NWS said about the moisture with the last arctic air that moved down this past December. My father in law who works right on the shoulder of I-45N in Willis had a 25 to 30 minute snow shower. While he was getting these flurries I checked the radar and didn't see a thing. Their were alot of other reports also coming from The Woodlands area, Cleveland and up in my neck of the woods up towards Conroe. Personally I didn't see any but apparently alot of other people saw some flurries. Like you said, you never know.

Really? I didn't see any either. I had heard of those reports, seemed like everyone was seeing a flurry except for me...

But you make a good point. You just never know what might happen!

[LAwxrgal]

FWIW, the current forecast for my area starting tomorrow and going thru Sunday night. From NWS New Orleans.


THURSDAY
PARTLY CLOUDY. HIGHS IN THE MID 50S. NORTH WINDS
10 TO 20 MPH DECREASING TO LESS THAN 10 MPH IN THE AFTERNOON.

THURSDAY NIGHT
PARTLY CLOUDY. LOWS IN THE LOWER 30S. LIGHT AND
VARIABLE WINDS.

FRIDAY
MOSTLY CLOUDY. CHANCE OF RAIN SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS IN THE AFTERNOON. HIGHS IN THE LOWER 60S. LIGHT
AND VARIABLE WINDS. CHANCE OF SHOWERS AND THUNDERSTORMS
30 PERCENT.

FRIDAY NIGHT
MOSTLY CLOUDY. CHANCE OF RAIN SHOWERS AND SLIGHT
CHANCE OF THUNDERSTORMS IN THE EVENING...THEN CHANCE OF RAIN
SHOWERS AFTER MIDNIGHT. NOT AS COOL. LOWS IN THE MID 40S. CHANCE
OF SHOWERS AND THUNDERSTORMS 50 PERCENT.

SATURDAY
MOSTLY CLOUDY WITH A 20 PERCENT CHANCE OF RAIN
SHOWERS IN THE MORNING...THEN PARTLY CLOUDY IN THE AFTERNOON.
COOLER. HIGHS IN THE LOWER 50S.

SATURDAY NIGHT
MOSTLY CLEAR. COLDER. LOWS IN THE LOWER 30S.

SUNDAY
MOSTLY SUNNY. HIGHS IN THE MID 50S.

SUNDAY NIGHT
MOSTLY CLEAR. LOWS IN THE MID 30S.

Heck, they might have to change these variables if the recent GFS guidance is any indication. Highs in the lower 50s and lows in the lower 30s on Saturday night might be too warm.

[Tyler]

If Houston forecasts mid 50's for highs again saturday, I'M GOING TO SCREAM! Also, if they go any warmer than upper 20's for lows saturday night, I'm going to... SCREAM AGAIN!

BTW, first couple of Euro maps coming up on Plymouth, high at 48 hours 1047MB over NW Canada. That is stronger than 0z run by about 5MB so far...

[LAwxrgal]

The local met forecast a high on Saturday of 50 degrees, and an overnight low in the mid 20s, and said some isolated spots could see low 20s. That's more in line with the guidance, I would suppose.

[Tyler]

The high on Saturday is NOT going to be 50. You can take that to the bank. All of SE TX and LA will be stuck in the 40s with VERY strong cold air advection and cloudy conditions, the strongest we've seen this season. The forecasted lows are ok however.

[Tyler]

day 3 12z ECMWF, 1045 high over Colorado!

850 Temps Day 3 12z ECMWF:

[Johnny]

It's gonna be very interesting to see how the temperatures pan out with this arctic air.

Back to the mini December arctic intrusion....the front came through Wednesday evening and into the night. The next morning I woke up and it was 29 degrees and falling. By the time I left to go to work it was 27 degrees. I checked the forecast before I left to go to work and the NWS was calling for a high in the lower to mid 40's. Shoot, my area stayed below freezing for the remainder of the morning period and we got up to 34 right around 2:30 that afternoon and then that was it!

[southerngale]

At the aiport, it said you guys hit 29.

http://www.srh.noaa.gov/data/obhistory/KAUS.html

You guys would probably be around 20 next weekend.

Let me tell you about that. The ASOS station at the airport is notorious around these parts for really being off from the rest of the real world. I don't know if it's because it is in a depressed (geographically speaking) area or what but the reading from Camp Mabry is much more reliable and in keeping with other observed temps in the city.

By the way, case in point on this topic ... Austin Bergstrom ASOS showed an air temp of 30 degrees at around 1 a.m. this morning while Camp Mabry (about 5 miles away and near the city) showed 45 degrees. That is a 15-degree differential!

The Mabry readings are a lot more accurate than what the airport registers.

Yeah but Bergstrom is in a valley and there is always a differences, sometimes big. Which makes me question why they take the temperature for Austin, not in Austin. Someone tell me why they did that one?? Another brillant thought by some governement official....

Yeah, the official temp/rain, etc. for Beaumont is officially taken in Port Arthur. lol (I know they're close, but come on...not one place in the city for the official readings?)
Since Beaumont is slightly north of Port Arthur, it's usually colder in Beaumont than what they officially report for Beaumont.
Same thing with rain...Beaumont could be flooding and NWS or TWC might show "light showers" or "drizzle" or "cloudy" - meanwhile, rain is falling at a 3"/hr. rate or something.
Smart thinking!

[Johnny]

Sorry man but if the high is centered over Colorado than we will be even colder. This air looks colder than what we saw in early December. If it stays cloudy for most of the day on Saturday with a persistent strong northerly flow...I don't see us getting out of the 30's.

[southerngale]

Lovely 850MB temp maps for all to enjoy:
NOTE: This run of the 12z GFS is MUCH colder.

Hour 60:


Hour 66:


Hour 72:


Hour 78: coldest point


Hour 84:

Actually, hour 84 is the coldest point. The purple reaches the coast.