Friday, November 23, 2012

Early Morning European Model Update

We have an even bigger dilemma this morning with the European model.  It has pushed the storm even further south and east,  continuing to suggest that the storm will remain so far south of our area and keeping us so cold,  that it actually misses us, while the American model brings the storm North of us and warms us up so much that we get rain.  Therefore, I am going to continue with my current forecast of snow for our area, as I continue to believe that the truth lies somewhere in between these two models, and that would be similar to the ensemble mean of the American model, and yesterday's ensemble mean of the European model. The main office for the National Weather Service outside of Washington D. C. agrees with me this morning, so I am in good company, but wow is this forecast getting interesting and complicated.   Check back later for my daily forecast.  Below is the forecast discussion from the National Weather Service headquarters.  Keep in mind; these are the top forecasters in the country, so it really shows how difficult this forecast is becoming.  

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
305 AM EST FRI NOV 23 2012

VALID 12Z TUE NOV 27 2012 - 12Z FRI NOV 30 2012

GENERAL FLOW PATTERN
====================
A REPETITION OF THE PATTERN SEEN OVER THE PAST FEW WEEKS IS
EXPECTED, WITH AN AMPLIFIED TROUGH MOVING INTO THE EASTERN
PACIFIC, WITH DOWNSTREAM RIDGING FORMING ACROSS THE WEST AND
PLAINS, AND RENEWED TROUGHING ANTICIPATED ACROSS THE NORTHEAST,
THOUGH THE RIDGE/TROUGH COUPLET OVER THE LOWER 48 IS EXPECTED TO
BE COMPOSED OF BROAD FEATURES OF RELATIVELY LOW AMPLITUDE, WHICH
LEADS TO QUICK SHORTWAVE MOVEMENT THROUGH THE COUNTRY.

MODEL PREFERENCE
================
MODEL ISSUES ARE SIGNIFICANT THIS PERIOD.  THE 00Z ECMWF BECOMES
VERY FAST WITH A SHORTWAVE MOVING THROUGH THE PLAINS MONDAY, AND
EVEN THOUGH ITS PATTERN ALOFT RESEMBLES THE ENSEMBLE MEAN SOLUTION
LATE NEXT WEEK, ITS PRESSURE PATTERN HAS BEEN SO CONTAMINATED BY
THIS QUICK-MOVING SHORTWAVE ACROSS THE EAST AND WESTERN ATLANTIC,
ITS SOLUTION COULD NOT BE USED.  THE 00Z GFS BROKE DOWN THE
WESTERN RIDGE WEDNESDAY MORNING BY USING A FORMERLY CLOSED LOW TO
DO SO, AND DOES NOT CONVERGE WITH THE REMAINDER OF THE GUIDANCE
UNTIL DECEMBER 1ST, SO ITS SOLUTION WAS NOT USED EITHER.  THE 00Z
CANADIAN SHARPENS THE BASE OF THE SHORTWAVE MOVING THROUGH THE
PLAINS EARLY ON, AND SENDS A DEEP CYCLONE ACROSS THE CENTRAL
APPALACHIANS INTO THE MID-ATLANTIC STATES WHICH SHOWS LITTLE
RESPECT TO THE COOL AIR IN ADVANCE OF THE FEATURE (NO OBVIOUS COLD
AIR DAMMING).  THE CANADIAN SOLUTION IS ON THE SLOW SIDE OF THE
12Z GLOBAL ENSEMBLE ENVELOPE TO BOOT, AND CONSIDERING THE
RELATIVELY LOW AMPLITUDE FLOW, ITS SOLUTION SHOULD BE QUICKER AND
POSSIBLY WEAKER HERE, SO ITS SOLUTION WAS NOT BE USED EITHER. 

PER THE ABOVE, THE PRESSURES USED A 00Z UKMET TEMPLATE THROUGH
TUESDAY BEFORE TRANSITIONING TO A 50/50 BLEND OF THE 00Z GEFS/12Z
ECMWF ENSEMBLE MEAN SOLUTIONS.  THE 00Z UKMET SOLUTION WAS NOT
PERFECT EITHER, SHOWING QUICKER PROGRESSION THAN ANTICIPATED BY
THE ENSEMBLE LOW CLUSTERING ACROSS THE EAST AND WESTERN ATLANTIC,
SO SHIFTED ITS LOW PRESSURE CENTER TOWARDS 12Z GLOBAL ENSEMBLE
CLUSTERING TUESDAY AND WEDNESDAY.  CONSIDERING THE DETERMINISTIC
MODEL SPREAD THIS PERIOD, THE RELATIVELY LOW AMPLITUDE FLOW ACROSS
THE LOWER 48 UNITED STATES, AND THE LACK OF AN OVERALL GOOD
DETERMINISTIC MODEL CHOICE, CONFIDENCE IS BELOW AVERAGE IN THIS
PREFERENCE.

ROTH











No comments:

Post a Comment

Note: Only a member of this blog may post a comment.