714
FXUS10 KWNH 070445
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1144 PM EST THU FEB 06 2020
VALID FEB 07/0000 UTC THRU FEB 10/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH LATEST MODEL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..PHASING TROUGHS OVER THE MID-ATLANTIC/NORTHEAST ON FRIDAY
..POWERFUL SURFACE LOW CENTER ADVANCING THROUGH THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS REFLECT NORTHERN STREAM ENERGY CURRENTLY OVER PORTIONS
OF THE UPPER GREAT LAKES AND MIDWEST THAT WILL DIG SOUTHEAST AND
PHASE ON FRIDAY WITH THE STRONG EJECTING SOUTHERN STREAM TROUGH
OVER THE TN VALLEY AND GULF COAST STATES. THE PHASING OF THESE
SYSTEMS WILL LEAD TO A CONSOLIDATED, BUT VERY POWERFUL AREA OF LOW
PRESSURE OVER THE INTERIOR OF THE MID-ATLANTIC AND ESPECIALLY NEW
ENGLAND BY LATE IN THE DAY. IN FACT, LOCALLY IN A FEW SPOTS ACROSS
THE NORTHEAST, IT IS EXPECTED THAT THERE WILL BE ALL-TIME LOW
SURFACE PRESSURE RECORDS SET FOR THE MONTH OF FEBRUARY. THIS LOW
CENTER WILL THEN EXIT VERY QUICKLY NORTHEAST THROUGH THE CANADIAN
MARITIMES FRIDAY NIGHT AND EARLY SATURDAY. MODEL SPREAD IS VERY
MODEST, SO A GENERAL MODEL BLEND WILL BE PREFERRED.
..SHORTWAVE CROSSING THE PLAINS AND OH VALLEY BY SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/12Z CMC/12Z ECMWF
CONFIDENCE: ABOVE AVERAGE
STRONG FLOW WILL CONTINUE TO OVER-TOP A BROAD BUT DOMINANT EASTERN
PACIFIC/WEST COAST RIDGE AXIS THROUGH FRIDAY WHICH WILL ALLOW
SUBTLE SHORTWAVE ENERGY CRESTING THE RIDGE TO DIVE SOUTHEAST
ACROSS THE CENTRAL/NORTHERN PLAINS BY FRIDAY EVENING AND THEN
ACROSS THE OH VALLEY ON SATURDAY. A WEAK AREA OF SURFACE LOW
PRESSURE AND A FRONT WILL BE ASSOCIATED WITH THIS ENERGY. THE 00Z
NAM IS A TAD SLOWER AND OCCASIONALLY A LITTLE DEEPER THAN THE
GLOBAL MODELS AS THE ENERGY TRAVERSES THE MIDWEST. MEANWHILE, THE
12Z UKMET APPEARS TO BE PERHAPS A LITTLE TOO FLAT AND PROGRESSIVE.
OVERALL THE MODEL SPREAD IS MODEST, BUT WILL PREFER A SOLUTION
TOWARD A 00Z GFS/12Z CMC/12Z ECWMF CONSENSUS AT THIS TIME.
..DEEP TROUGH/CYCLONE CROSSING THE PACIFIC NORTHWEST SATURDAY
..DIGGING ENERGY OVER THE GREAT BASIN/SOUTHWEST BY SUNDAY
..DOWNSTREAM TROUGHING OVER THE NORTHERN PLAINS BY SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A STRONG CLOSED LOW WILL ADVANCE THROUGH THE ALEUTIAN ISLANDS AND
AK PENINSULA BY EARLY FRIDAY, WITH STRONG SHORTWAVE ENERGY THEN
DIGGING QUICKLY SOUTHEAST TOWARD BRITISH COLUMBIA AND THEN ACROSS
THE PACIFIC NORTHWEST FRIDAY NIGHT THROUGH EARLY SATURDAY. BY
SUNDAY, A PORTION OF THIS INITIAL SURGE OF ENERGY WILL QUICKLY
EJECT DOWNSTREAM ACROSS THE NORTHERN ROCKIES AND OVER THE NORTHERN
PLAINS. MEANWHILE, A SPLIT IN THE UPPER FLOW WILL ALLOW FOR A
SUBSTANTIAL AMOUNT OF ENERGY TO THEN DIG SOUTHWARD OVER THE GREAT
BASIN AND INTO THE SOUTHWEST AROUND THE EASTERN SIDE OF A STRONG
DEEP LAYER RIDGE DEVELOPING OFFSHORE THE WEST COAST THIS WEEKEND.
THE 12Z UKMET QUICKLY BECOMES A PROGRESSIVE OUTLIER AS THE ENERGY
ARRIVES ACROSS THE PACIFIC NORTHWEST AND WITH THE SPLIT FLOW
PORTION OF THE ENERGY DROPPING DOWN THROUGH THE SOUTHWEST. THE
REMAINING GUIDANCE IS REASONABLY WELL CLUSTERED OTHERWISE AT LEAST
WITH THIS PORTION OF THE HEIGHT FALLS. MEANWHILE, THE NORTHERN
STREAM ENERGY BREAKING AWAY AND CROSSING THE PLAINS AND UPPER
MIDWEST THROUGH SUNDAY WILL BE ACCOMPANIED BY A WAVE OF LOW
PRESSURE AND A NEW FRONTAL ZONE. THE 00Z NAM GRADUALLY BECOMES A
LITTLE SLOWER THAN THE GLOBAL MODELS AT THE SURFACE, AND AT LEAST
ALOFT MAY BE A TAD TOO DEEP. THE 12Z UKMET FOR ITS PART IS A
LITTLE MORE PROGRESSIVE AT LEAST AT THE SURFACE.
OVERALL, THE 00Z GFS AND 12Z UKMET HAVE THE BEST MODEL CLUSTERING
AND ENSEMBLE SUPPORT, SO A BLEND OF THESE SOLUTIONS WILL BE
PREFERRED WITH THE ENERGY AS IT ARRIVES ACROSS THE NORTHWEST, AND
THEN ALSO WITH THE SPLIT FLOW EVOLUTION THEREAFTER.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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