Latest HPC discussion=DC,Demarva target for heavy snow

[cycloneye]

VALID 12Z FRI JAN 21 2005 - 12Z TUE JAN 25 2005

FINAL MEDIUM RANGE DISCUSSION...

...SNOWSTORM INDICATED BY SEVERAL MODELS FOR OH VALLEY AND MID ATL
STATES THIS WEEKEND...

MAJORITY OF NEW GLOBAL GUIDANCE FROM 12Z/18 IS CONVERGING ON
WINTER STORM FROM THE MIDWEST TO THE MID ATL STATES DAYS 4 AND 5.
06Z/18 OPERATIONAL GFS WAS USED TO CREATE MANUAL PROGS...WITH NEW
OPERATIONAL GFS...NOGAPS...CANADIAN GLOBAL...AND UKMET SUPPORTING
ITS SOLUTION...AS WELL AS 06Z/18 DGEX. 12Z/18 GFS IS A LITTLE
FARTHER S WITH SYSTEM THAN THE 06Z/18 RUN...AND IF TAKEN
LITERALLY...WOULD WALLOP THE DC AREA AND DELMARVA WITH HEAVY SNOW.
PRIMARY LOW TRACKS SEWD THRU THE MIDWEST DAYS 3 AND 4...WITH
SECONDARY DEVELOPING INVOF CAPE HATTERAS AROUND DAYBREAK SUN...DAY
5. LOW THEN TRACKS ENEWD INTO ATL...SUPPRESSSED BY CONFLUENCE
OVER THE CANADIAN MARITIMES. SWATH OF MODERATE TO HEAVY SNOW IS
EXPECTED JUST N OF TRACK OF MIDWEST LOW...WITH WARM ADVECTION
SNOWS DEVELOPING EARLY DAY 4 OVER MID ATL...ENHANCED BY LOW LEVEL
DAMMING. COUPLED SUBTROPICAL AND POLAR JETS OVER THE ERN US SAT
IS WHAT WOULD SUPPORT THE MODEL SOLUTIONS OF PRIMARY LOW TRACKING
SO FAR S...WITH CONFLUENCE OVER SERN CANADA ASSURING THE STEADY
SUPPLY OF FRIGID AIR. ONCE COASTAL TAKES OVER SUN...COMMA HEAD
WOULD KEEP A STEADY...BUT LIGHTER SNOW...FALLING OVER THE ERN MID
ATL UNTIL DARK.

FLY IN THE OINTMENT IS LATEST RUN OF ECMWF WHICH IS FARTHER N AND
SLOWER WITH WHOLE EVENT...VERY REMINISCENT OF THE 00Z/18 UKMET.
IT TAKES ITS PRIMARY LOW ACROSS LAKE ERIE EARLY SUN...THEN SPINS
UP A REAL STEMWINDER E OF NEW ENGLAND MON. IN THIS MODELS FAVOR
IS CLIMATOLOGY...WHICH TEACHES US THAT ATL STORMS THAT FORM AS
SECONDARIES FROM A MIDWESTERN SYSTEM TYPICALLY AFFECT AREAS FROM
NYC NWD. BUT...ARGUMENT AGAINST IT...AND REASON WHY MANUAL PROGS
STILL FAVOR MORE SRN SOLUTION...IS THAT THE RUN IS NOW ON ITS OWN
WITH ITS SOLN...EVEN CONTRADICTED BY ITS EARLIER ITERATIONS.

Still finetuning of the track of the low has to be determined but it looks like DC will see bigtime snow.

[Lowpressure]

Will be watching it closely, thanks for the info Cyclone. Local media starting to rumble a bit.

[JenyEliza]

I have a (completely) novice question, so forgive me if I appear to be asking something stupid.

But...here goes anyway.....

Check out this satellite image, and note the plume of moisture from as far west as Baja, passing over Mexico, and into southern Texas.

Seems to me, that this could be moving eastward and might possibly meet up with the storm that's coming this weekend. Is this possible? Has anyone else noticed this? IF this were to happen, how would this impact the coming events? Any thoughts?

[PurdueWx80]

I have a (completely) novice question, so forgive me if I appear to be asking something stupid.

But...here goes anyway.....

GREAT observation, and in fact, the southern stream feature that may phase with the northern branch is located at the western end of this moisture just west of the Baja Peninsula. It isn't evident on the IR image you that posted, but the upper low is out there...check out a water vapor loop. That thing will sit and spin, and perhaps even retrograde for a bit, but most models move it eastward late this week, just in time for the northern branch to dig in and grab the subtropical moisture associated with it.

[JenyEliza]

I have a (completely) novice question, so forgive me if I appear to be asking something stupid.

But...here goes anyway.....

GREAT observation, and in fact, the southern stream feature that may phase with the northern branch is located at the western end of this moisture just west of the Baja Peninsula. It isn't evident on the IR image you that posted, but the upper low is out there...check out a water vapor loop. That thing will sit and spin, and perhaps even retrograde for a bit, but most models move it eastward late this week, just in time for the northern branch to dig in and grab the subtropical moisture associated with it.

So, this could move right into the path of the system?

I'm not a Met, not even an amateur...but I've lived in the SE long enough to know that when you've got cold coming down from the north and warm moist air coming from Mexico/the Gulf, and they meet....they make LOTS of little snow-flake babies!

The question is IF they meet, and where!

Jeny

[cycloneye]

That is why the models are not in total agreement about the eventual track of the storm some go more north and others a little south but without any doubt a big decent snowstorm will affect portions of the mid-atlantic.

[Tip]

Purdue, question?
I have heard the term 3 stream phaser/planetary wave tossed about but have never really understood it. Does it mean there has to be a disturbance in each of the jetstreams that come together or something else? I just looked at the 18z ETA at 500mb and it shows a disturbance represented by the black "x" in the southern jet, polar jet and arctic jet trying to lock up in one longwave. Thanks in advance

[BlizzardNole]

Ojala que si porque a mi me encanta la nieve!

In DC you learn to never get too excited until you see the radar lighting up with snow moving in. At least we have some hope though.

Cycloneye: has visto nieve en tu vida? Donde?

[cycloneye]

Ojala que si porque a mi me encanta la nieve!

In DC you learn to never get too excited until you see the radar lighting up with snow moving in. At least we have some hope though.

Cycloneye: has visto nieve en tu vida? Donde?

Si cuando muy nino yo estaba en Nueva York y vi una gran nevada.

Yes as a little boy in NY City I saw a Blizzard but now in Puerto Rico nada. Warm Temps all year long

[wxguy25]

Ojala que si porque a mi me encanta la nieve!

In DC you learn to never get too excited until you see the radar lighting up with snow moving in. At least we have some hope though.

Cycloneye: has visto nieve en tu vida? Donde?

Si cuando muy nino yo estaba en Nueva York y vi una gran nevada.

Yes as a little boy in NY City I saw a Blizzard but now in Puerto Rico nada. Warm Temps all year long

Digame sobre el Ningunas ventiscas aqui en la Florida tampoco.

[cycloneye]

Ojala que si porque a mi me encanta la nieve!

In DC you learn to never get too excited until you see the radar lighting up with snow moving in. At least we have some hope though.

Cycloneye: has visto nieve en tu vida? Donde?

Si cuando muy nino yo estaba en Nueva York y vi una gran nevada.

Yes as a little boy in NY City I saw a Blizzard but now in Puerto Rico nada. Warm Temps all year long

Digame sobre el Ningunas ventiscas aqui en la Florida tampoco.

Yeah no snow there wxguy but at least you have some frosty nights.

[wxguy25]

Ojala que si porque a mi me encanta la nieve!

In DC you learn to never get too excited until you see the radar lighting up with snow moving in. At least we have some hope though.

Cycloneye: has visto nieve en tu vida? Donde?

Si cuando muy nino yo estaba en Nueva York y vi una gran nevada.

Yes as a little boy in NY City I saw a Blizzard but now in Puerto Rico nada. Warm Temps all year long

Digame sobre el Ningunas ventiscas aqui en la Florida tampoco.

Yeah no snow there wxguy but at least you have some frosty nights.

ah la helada bien no lo corta... cuando su del noreste; usted tiende PARA CONTAR con mas. LOL!!

(hope I got that right. Its been awhile since I've written in Spanish)

[cycloneye]

Yes that spanish is not the best. So my friend let's post all in plain english because the members may be asking what we are talking about.

[Brent]

English please?

[BlizzardNole]

wxguy25: I was in Tallahassee once when we had snow for a while -- it didn't stick, but came down pretty good. The native Floridians were going nuts LOL!

[wxguy25]

wxguy25: I was in Tallahassee once when we had snow for a while -- it didn't stick, but came down pretty good. The native Floridians were going nuts LOL!

When was this?

[BlizzardNole]

I believe it was early February 1988 -- cold rain mixed with sleet before midnight, and people thought it was hail -- LOL! It went over to some moderate, wet snow for a half hour or so. Nice, big cottonball flakes. Many of those kids had never seen snow before and they were running around yelling and catching flakes in their mouths. It was pretty funny. Never even stuck though.

[Brent]

Wasn't there snow around Christmas of 1989 down there? That massive cold outbreak?

[Persepone]

I LOVE to see the occasional Spanish on this board! I'm also interested that I can figure most of it out... I notice that those who post in Spanish tend to post a translation below anyway--which is why you can learn from it.

So don't be too rigid about enforcing the "no Spanish"--that's one of the things that makes this board so much fun!

[cycloneye]

I LOVE to see the occasional Spanish on this board! I'm also interested that I can figure most of it out... I notice that those who post in Spanish tend to post a translation below anyway--which is why you can learn from it.

So don't be too rigid about enforcing the "no Spanish"--that's one of the things that makes this board so much fun!

Si yo siempre posteo en ingles despues que lo hago en espanol para que los que no entiendan el idioma sepan lo que estoy hablando.

I post in english after I do so in spanish because I know that the majority of the members want to know what I am talking about.