February 1-5, 2011 Arctic Blast/Winter Storm Discussion

[wxman666]

SPC depicts possible severe wx threat for us tomorrow evening, and mentions a slight risk upgrade will be considered in later outlooks. Something to watch closely...esp. with the marathon on Sunday.


http://www.spc.noaa.gov/products/outlook/day2otlk.html

[Mark25]

What's the verdict on the 12z Euro? Trying to predict next weeks events is like going to Vegas.

[tireman4]

so wxman57, you are Jeff Lindler?

His first name is Heat...last name Miser......

[harpman]

What's the verdict on the 12z Euro? Trying to predict next weeks events is like going to Vegas.

Must not be good.

[ejburas]

I think everyone is just a bit busy, that's probably why no one has posted it.

[harpman]

If it was good, believe me, someone would have posted it.

[randybpt]

Andrew ...hard freeze to me.is lower than 25 and I will take that bet we.will be lucky to see 28 during this hole EVENT

[hriverajr]

When is the upper low off of California supposed to eject across Texas? Tomorrow... No way.. if anything its has retrograded slightly south and west, good moisture feed starting to come across Mexico. Also looking at what is going on.. very strong pressure rises on the Canadian border. The pressure rises seem to be oriented in a north south manner, unlike what you might have if the air was going to move more southeast. Colder air is already coming across the border. Winds sustained at 25 to 30 Kts. I kind of doubt the cold air would get caught up in north Texas. What it all means.. If I did not have any models to look at. I would say cold air is coming into Texas in a pretty impressive manner.

[snowman65]

I'm with Randy on this one...I say we bottom out at 30.....

[weatherguy425]

Guys, everyone needs to just lie back in chill. It is typical for models to "go crazy" during 4-7 day time frame. The facts are that the cold air is already up there, and beggining it's move south. It of course is too early to say specifics but its very arrogant to write off the potential just because of what? 2 runs! Give it as few days as wxman and other pro mets have alreadyyyy stated.

[Andrew]

I'm on my phone so I can't really post much. Euro is about as cold as 00z. I'll post my reasoning and feelings later tonight when I get home.

[tireman4]

I'm with Randy on this one...I say we bottom out at 30.....

Read this from a pro-met...this is the "lost radio contact stage" of the models folks..



Candy Cane:

Order in the court! Order in the court!

Wowzers, a couple of 'warm' runs overnight and everybody is freaking out. May I be allowed to indulge myself here just a sec? Thanks.

I watched the movie Apollo 13 not long ago (great movie) and this airmass reminds me of a certain part at the end. In real life, as portrayed in the movie, the rocket is heading back towards Earth. All the scientists and journalists are telling the public how the rocket will enter the atmosphere and there will be a communications blackout upon entry. However, it'll regain it's communication when it breaks through into the troposphere. See all along, we've been shown time and time again that the arctic boundary is coming. In a sense, we have told the public what we can expect. It's going to happen a certain way and it's going to get cold. However, if the rocket comes in too shallow or too heavy, it'll either burn up or skip off the atmosphere like a rock on a pond and will have no hope of recovery. This is our area of low pressure. The low over the Pacific is, imo, what is throwing the models. Anyway, right now we've entered our 'communications blackout' as the models often like to lose cold air in this range. Once we start coming into Day 3 and 4, the idea is that they will once again snap back into place and 'see' the cold air once more. But it's all about the low. That low could give us a zonal flow and cause the arctic boundary to significantly modify if it is not progressive. Anyway, I'm not sure if that made sense, but it did in my head. LOL. Okay, off to work with me.

[srainhoutx]

HPC Final Update:

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
136 PM EST FRI JAN 28 2011

VALID 12Z MON JAN 31 2011 - 12Z FRI FEB 04 2011



...MAJOR WINTER STORM SETTING UP NEXT WEEK FROM THE ROCKIES TO THE
NORTHEAST...


MEDIUM RANGE GUIDANCE IS AGREEABLE WITH THE LARGE SCALE SCENARIO
OF AN ELONGATED MEAN TROF EXTENDING FROM NERN CANADA SWWD INTO THE
SWRN CONUS... LIKELY WITH SOME SEPARATION BETWEEN SRN CANADA/NRN
TIER CONUS FLOW AND WRN/SRN CONUS FLOW. THIS TROF WILL BE
SUPPORTED BY A MEAN RIDGE THAT SHOULD PERSIST OVER THE ERN PAC/WRN
CANADA ALBEIT WITH SOME CHANGE IN SHAPE OVER TIME. WHILE A GOOD
CONSENSUS EXISTS WITH THE LARGE SCALE MEAN EVOLUTION... THERE IS
LOWER THAN AVERAGE CONFIDENCE IN DETAILS DUE TO THE SPLIT FLOW
NATURE OF THE NOAM PATTERN AND ADDITIONAL UNCERTAINTIES PRESENTED
BY ERN PAC ENERGY THAT MAY TRY TO PASS THRU THE MEAN RIDGE BY
MID-LATE WEEK.

THE MOST PROMINENT SFC SYSTEM FOR WHICH SHRTWV UNCERTAINTIES COME
INTO PLAY IS FCST TO TRACK NEWD FROM THE SRN PLAINS TUE ONWARD.
TO VARYING DEGREES THE 00Z GFS AND ECMWF HAVE MADE MEANINGFUL NWWD
ADJUSTMENTS FROM FAIRLY SUPPRESSED TRACKS IN MULTIPLE PREVIOUS
RUNS. THE ECMWF TREND IS MORE EXTREME AS ITS PREVIOUS TWO RUNS
WERE ON THE SERN SIDE OF THE ENVELOPE AND THE NEW 00Z RUN IS NOW
ON THE NWRN SIDE OF GUIDANCE. THE CANADIAN IS A FAST EXTREME TO
BRING SWRN CONUS ENERGY INTO THE PLAINS AND IS ALSO IN THE NWRN
PART OF THE SPREAD... WHILE THE UKMET TRACK IS NOT QUITE AS FAR
NWWD AS ITS PREVIOUS RUN. OVERALL PREFER A GEFS MEAN/12Z ECMWF
ENSEMBLE MEAN SOLN THAT FALLS IN THE MIDDLE OF LATEST AND RECENT
GUIDANCE GIVEN THE SENSITIVITY OF SHRTWV DETAILS AND SIGNIFICANT
RUN TO RUN CONTINUITY CHANGES.

BEHIND THIS SYSTEM... BY WED NIGHT-FRI THERE IS CONSIDERABLE
SPREAD REGARDING ENERGY THAT MAY TRY TO PASS THRU THE ERN PAC MEAN
RIDGE. THE 00Z ECMWF AND SLOWER 00Z GFS BOTH SEEM A LITTLE STRONG
SO THE ENSEMBLE MEAN BLEND USED FOR THE PLAINS/ERN CONUS SYSTEM
PROVIDES A MORE TOLERABLE SOLN AT THIS TIME. THE GEFS MEAN IS A
LITTLE EXTREME WITH ITS SLOWER TIMING/WWD ELONGATION OF THE TROF
SETTLING OVER THE SWRN CONUS SO INCLUSION OF THE ECMWF MEAN TONES
DOWN THIS ASPECT OF THE FCST.

WHILE DAYS 5-7 WED-FRI FOLLOW A BLEND OF THE GEFS/12Z ECMWF
MEANS... MISSING DATA DUE TO EARLIER COMMS ISSUES PRECLUDED USE OF
THE ECMWF MEAN FOR DAYS 3-4. THUS THE EARLIER PART OF THE FCST
STARTED WITH A BLEND OF GFS/ECMWF/GEFS MEAN SOLNS TO ARRIVE AT AN
ACCEPTABLE COMPROMISE.

UPDATED MORNING PRELIMS USE A MULTIMODEL BLEND OF 00Z
GFS/ECMWF/CMC/UKMET/GFS ENS MEAN. THE RESULT IS NEARLY IDENTICAL
TO THE EARLIER USED SOLUTION.

12Z MODEL GUIDANCE FOLLOWS CONTINUITY AND A COMPOSITE OF THE RUNS
WOULD CONTINUE TO YIELD THE BLENDED SOLUTION OF HPC. NO CHANGES
FOR AFTERNOON FINALS.

AS SHORTWAVE ENERGY MOVES INTO THE FOUR CORNERS REGION EARLY
TUESDAY AND ARCTIC HIGH PRESSURE PLUNGES DEEP INTO THE PLAINS WITH
GREATER THAN 20 DEGREE NEGATIVE TEMPERATURE ANOMALIES. THIS WILL
BRING STRONG UPSLOPE FLOW INTO THE CO ROCKIES FRONT RANGE WITH
MDT/HVY SNOWFALL TO THE SRN ROCKIES SPREADING EWD INTO THE CENTRAL
PLAINS. MID LEVEL ENERGY SHEARS OUT EWD AND A MDT SFC LOW DEVELOPS
OVER ERN TX BY TUESDAY. THIS LOW MOVES NEWD INTO KY/TN WED AND
REFORMS OFF THE MID ATLC CAPES AND RAPIDLY MOVES NEWD OFF NOVA
SCOTIA BY THURSDAY. MDT TO HVY RAINFALL POTENTIAL SOUTH OF THE LOW
PRESSURE TRACK WITH SNOW ACROSS THE CENTRAL PLAINS AND MAINLY
NORTH OF THE OH RIVER AND MASON DIXON LINE INTO NEW ENG. HEAVY
SNOW THREAT INDICATED BY OPERATIONAL MODELS QPF OUTPUT/ANALOGS AND
FAVORABLE MID AND UPPER LEVEL JET STRUCTURE WITH ICING THREAT
ALONG THE CHANGE OVER AND THEN THE DAMMED IN AREA IN THE MID ATLC
PIEDMONT.

PACIFIC RECON FLIGHTS REQUESTED INTO THE CRITICAL UNCERTAINTY AREA
AHEAD OF THIS SYSTEM IN THE NE PACIFIC. IF A FLIGHT IS AVAILABLE
THIS DATA COULD GET INTO THE MODEL SYSTEMS BY THE RUNS OF SUNDAY
00Z/12Z 30 JAN.

RAUSCH/ROSENSTEIN

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS
2. SUCCEEDING DAY OUTLOOK:
A. P73/ 43.9N 172.3E(DROP 11)/ 30/1200Z


Second Mission added as well today for Monday...

NOUS42 KNHC 281700
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1200 PM EST FRI 28 JANUARY 2011
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
VALID 29/1100Z TO 30/1100Z JANUARY 2011
WSPOD NUMBER.....10-059

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

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS
2. SUCCEEDING DAY OUTLOOK:
A. P71/ 44.9N 170.7E(DROP 11)/ 31/1200Z

[Baseballdude2915]

To all wondering the 12z Euro is warm. Not even freezing for us.
Does give Dallas a bit of chilly air, the 850mb -10c isotherm gets close to them around hour 144.
It seems like we are stuck on the verge of decent cold air. Why would it just stop?
Could be a model error, but this event really isn't looking to be much of one anymore.

Now the models are picking up on an event around the 8th or 9th.. lets watch as that one teases soon. LOL

[wxman57]

To all wondering the 12z Euro is warm. Not even freezing for us.
Does give Dallas a bit of chilly air, the 850mb -10c isotherm gets close to them around hour 144.
It seems like we are stuck on the verge of decent cold air. Why would it just stop?
Could be a model error, but this event really isn't looking to be much of one anymore.

Now the models are picking up on an event around the 8th or 9th.. lets watch as that one teases soon. LOL

Actually, the 12Z Euro 2 meter temperature forecast is for about 28-29 degrees for Houston next Thursday. But it is about 10 degrees "warmer" than the 12Z run yesterday.

[BiggieSmalls]

From now on, whatever we think the % chances are of something happening, cut it in half; THAT is pretty much a universal rule to follow in the winter I think.

While Dallas may still see something here, it isn't anything special to get 25 or 26 and in the 30s during the day. We had that 2 weeks ago.

[Ptarmigan]

The GFS model from last week did not see any rain earlier this week, Sunday/Monday. Guess what? It rained and it was all day. They seem to have problems at the last minute.

[srainhoutx]

Goodness. I have meetings all morning and come back and see folks were expecting something new today. It's been stated repeatedly that we'll likely not know the finer details until Sunday/Monday. We have 2 Winter RECON missions ahead and a Pacific storm brewing way off the Pacific NW Coast. Cold air is building and heading S as we can see by observations, real time. If we get rain and then cold, so be it. I suspect that we are witnessing a common modeling issue in the shorter medium range. Will it produce some wintry weather? That remains to be seen and certainly was no guarantee to begin with. The cold is coming. How cold? We will get a better feel for that over the weekend as well. Also look at the interest in this system (event). Where ever this storm goes or impacts, it looks to be a major winter event. I’ll remain cautious until we know exactly what this thing is going to do.

[tireman4]

Yeah, I agree. I am now thinking Monday will the day to shake things out. This is so mixed up, it will be almost right on us before we really know what is going on.

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including KHOU forum. For Official Information please refer to the NHC and NWS products.

[Andrew]

I just don't understand why people are being so heavily swayed by a couple batches of runs. It is too early yet to know what the exact temperatures are going to be but yet people feel like this is going to be a non event (as in the cold). The real time data as stated by srain above show the cold air already moving south into Canada and even with the models being warmer than yesterday still show temps in the mid 20's. It is a complicated setup and its not going to change anytime soon. You can see the difference from temps below: