Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

February Winter Storm Prospects


WeatherX

Recommended Posts

Another note I just caught, the 12Z RGEM at 48 hours is nothing like the NAM and resembles the UKIE/GEM/NOGAPS, the RGEM has the northern vort more SW over the UP of Michigan/Superior/Northern WI while the NAM is weaker and way east with it. It would appear to me there is a strong chance the RGEM would phase the system if it was run out to 60 or 72 hours.

Link to comment
Share on other sites

  • Replies 1.1k
  • Created
  • Last Reply

Another note I just caught, the 12Z RGEM at 48 hours is nothing like the NAM and resembles the UKIE/GEM/NOGAPS, the RGEM has the northern vort more SW over the UP of Michigan/Superior/Northern WI while the NAM is weaker and way east with it. It would appear to me there is a strong chance the RGEM would phase the system if it was run out to 60 or 72 hours.

New srefs made a sizeable jump north from 9z. Precip shield gets into southern NJ on the new one and at 9z precip didnt even make it into Virginia.

Link to comment
Share on other sites

New srefs made a sizeable jump north from 9z. Precip shield gets into southern NJ on the new one and at 9z precip didnt even make it into Virginia.

all the models jumping north at once is not a "blip" but don't be surprised if the 18z GFS does not - not sure if the new data is given to that model run for 18z.......might take till 0Z

New HPC statement

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

226 PM EST THU FEB 02 2012

VALID 12Z SUN FEB 05 2012 - 12Z THU FEB 09 2012

IN MOST RESPECTS THERE IS GOOD AGREEMENT AND CONTINUITY IN THE

LARGE SCALE PATTERN BY MID-LATE PERIOD AS A NARROW BUT VERY

AMPLIFIED WRN NOAM MEAN RIDGE BUILDS WELL N INTO CANADA AND ALASKA

BY TUE DAY 5...WHILE A BROADENING TROF ANCHORED BY A MEAN CLOSED

LOW JUST E/NE OF HUDSON BAY BECOMES THE DOMINANT FEATURE OVER ERN

NOAM.

GUIDANCE CONTINUES REASONABLY CONSISTENT IN SUGGESTING THAT

ELONGATED ENERGY NEARING THE WEST COAST TUE DAY 5 WILL

SPLIT...WITH THE STRONGER PORTION DROPPING SEWD TO SOMEWHERE OFF

THE SRN CA/BAJA COAST...AND NRN ENERGY WEAKENING WHILE PROGRESSING

THRU OR AROUND THE WRN NOAM MEAN RIDGE. THE LATEST 12Z/02 GFS

SOLUTION MAINTAINS 00Z CONTINUITY WITH A CLOSED LOW OVER CA WED

DAY 6 WHILE THE CANADIAN AND UKMET LANGUISH THE SYS FARTHER

OFFSHORE. THERE IS STILL A PCPN THREAT TO CA AROUND NEXT WED

DEPENDING ON HOW CLOSE THIS SYS GETS TO THE COAST.

THE MAIN MODIFICATION TO THE FINAL PROGS IN THIS PACKAGE WAS OVER

AND OFFSHORE THE E COAST STATES SUN/MON DAYS 3-4...WHERE WE PLAYED

UP THE INTENSITY OF THE SYS CROSSING TN/NC/VA AS PER THE 12Z/02

UKMET/CANADIAN/ECMWF. OTHERWISE FINAL PROGS KEPT THE IDEAS OF THE

UPDATED PRELIM. WE MAINTAINED THE 40-40 DETERMINISTIC ECMWF/GFS

20% FEFS MEAN BLEND FOR DAYS 6-7. THIS PRESERVED THE CHARACTER OF

THE AGREEABLE SHORT WAVE FEATURES OF THE GFS AND ECMWF MODELS.

EARLIER...WE HIGHLIGHTED A DIFFICULTY CONCERNING THE LOW LEVEL

COLD AIR SUN DAY 3 IN THE SRN MID ATLANTIC REGION. THE GFS 2M

TEMPS LOOKED WAY TOO WARM FOR DAY 3 MAX COMPARED TO TEMPS DERIVED

FROM THE ECMWF. PCPN OVER VA SUN DAY 3 WILL LIKELY BE FALLING INTO

A LAYER OF COLD AIR ADVECTING IN ON NE SURFACE WINDS. SUN AFTN

LOOKS EVEN COLDER FROM 12Z/02 GUIDANCE NOW THAT THERE IS BETTER

12Z MODEL CONSENSUS THAT THE NRN PORTION OF THE PCPN SHIELD WILL

BE SNOW....WITH SOME ACCUMULATION POSSIBLE. THE INTERESTING THING

IS THAT THE QPFS OF THE 12Z/02 GEFS ENSEMBLE MEAN...UKMET...AND

CANADIAN ARE SIGNFICANTLY HIGHER WITH THE QPF SUN BELOW THE MASON

DIXON LINE. THE CANADIAN IS THE MOST BULLISH OF THE NEW SOLUTIONS

AND BEGINS TO PHASE THE EJECTING PIECE OF ENERGY FROM THE PLAINS

STATES WITH NRN STREAM ENERGY SAT EVE TOPPING THE REX BLOCK OVER

FAR SWRN CANADA.

THE NEW 12Z GFS APPEARS TO HAVE DIFFICULTY HANDLING THE FATE OF A

TAIL OF ENERGY TRAILING THE SPLITTING CENTRAL CONUS CLOSED UPPER

LOW EARLY IN THE PERIOD...MORE APPARENT AT 500MB THAN AT THE

SURFACE. THE MAIN 12Z GFS DIFF FROM 00Z IS A FASTER FROPA ACROSS

THE NERN STATES TUE ASSOCIATED WITH THE ARCTIC STREAM. BY DAYS 6-7

THE NEW GFS SEEMS TO GET BACK IN LINE MORE WITH ITS 00Z

CONTINUITY. ENSEMBLE SPAGHETTI PLOTS AGREE REASONABLY WELL ON THE

PATTERN ACROSS THE CONUS ONCE THE MID ATLANTIC SYS MOVES OFFSHORE

LATER SUN INTO EARLY MON.

FLOOD

Link to comment
Share on other sites

A few of the GEFs members are similar to the EC/UK/GGEM et. al. with respect to the vort energy from Canada diving further SW into the midwest compared to the operational American models. A continuation of this trend alone could result in precip getting northward into some of the coastal metro cities.

But some sort of phasing is probably needed with the decaying cutoff for a significant storm. For meaningful phasing we need the cutoff to slip around to a neutral or downstream position with respect to the canadian vort before the developing trof axis passes east of the coastline. This could happen if the cutoff traverses eastward much more quickly or if the polar s/w digs further SW. A coastal low is possible, but it will probably develop too far offshore.

I think the polar s/w is the key here. I'll be watching closely for trends in this feature.

Link to comment
Share on other sites

Would like to see some more ridging near Greenland to force the PV further south, but other than that, I'm certainly intrigued about Feb 10-12th. Last winter, we didn't really have the huge PNA ridging...the block did pretty much everything for Boxing Day regarding buckling the pattern and forcing shortwaves from Canada to take a meridional path. Having a strong PNA ridge can also greatly help that in combination with the strong PV which can help to provide shortwaves to hopefully phase with the energy undercutting the PNA ridge.

But as I said before, I'd really like to see some of those features further south. Hopefully the PNA ridging is enough to compensate for the fact that we don't have a true NAO block - the NAO block compensated for our lack of the strong PNA ridge last year.

Link to comment
Share on other sites

Feb 10-12 has been the period discussed for a good majority of the last two weeks. Good to see he's on board.

What factor in addition to the trough and the western ridge would we need to see to result in an actual coastal storm or a Miller B in this time frame instead of just a cold front followed by cold?

Link to comment
Share on other sites

Would like to see some more ridging near Greenland to force the PV further south, but other than that, I'm certainly intrigued about Feb 10-12th. Last winter, we didn't really have the huge PNA ridging...the block did pretty much everything for Boxing Day regarding buckling the pattern and forcing shortwaves from Canada to take a meridional path. Having a strong PNA ridge can also greatly help that in combination with the strong PV which can help to provide shortwaves to hopefully phase with the energy undercutting the PNA ridge.

But as I said before, I'd really like to see some of those features further south. Hopefully the PNA ridging is enough to compensate for the fact that we don't have a true NAO block - the NAO block compensated for our lack of the strong PNA ridge last year.

Hopefully without the -NAO solidly in place, we can keep the low track offshore and cold enough for snow. I always worry in these majorly amplified patterns that a storm that develops will cut right for the Lakes or go inland because there's nothing stopping it upstream.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...