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March 6-8th Ocean Storm Discussion Part II

free_man

By free_man,
in New England

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Baroclinic Zone

Baroclinic Zone

Posted
Posted

And Kocin 12z model discussion.

 

 

MODEL DIAGNOSTIC DISCUSSIONNWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1110 AM EST MON MAR 04 2013VALID MAR 04/1200 UTC THRU MAR 08/0000 UTC...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIRINGEST......12Z NAM EVALUATION...MODEL INITIALIZATION ERRORS WILL BE DESCRIBED UNDER THE RELEVANTSYSTEM HEADING...STAGNANT UPR CYCLONE LINGERING ACRS COASTAL UPR NEW ENGLAND...THE UPPER LOW EAST OF MAINE BY MONDAY EVENING IS FINALLY FORECASTTO MOVE EASTWARD ON TUESDAY ALTHOUGH IT LEAVES BEHIND A WEAKDISTURBANCE OVER NEW ENGLAND ON TUESDAY NIGHT.  THE 12Z NAM HASSOME SLIGHT DIFFERENCES WITH THE OTHER OPERATIONAL MODELS BUT INGENERAL IS WITHIN A REASONABLE RANGE OF SOLUTIONS....PAIR OF DISTURBANCES INITIALLY OVER THE NORTHERN PLAINS ANDSWRN U.S......EVENTUAL MERGER AND AMPLIFICATION OVER THE MIDWEST LEADING TO SSIGNIFICANT UPPER LOW MOVING FROM THE LOWER OHIO/UPPER TENNESSEEVALLEY  TO THE MID ATLANTIC COAST ON TUESDAY TO WEDNESDAY...OVER THE PAST 24 HOURS...THE MODEL DIFFERENCES WITH THIS COMPLEXSYSTEM HAVE DIMINISHED ALTHOUGH THERE CONTINUES TO BE SYSTEMATICMODEL DIFFERENCES BETWEEN THE GFS/NAM CAMP AND THE ECMWF/UKMETCAMP.  THE NCEP MODELS...INCLUDING THE SREF ENSEMBLES/NAM/GFS/GEFS ARE SYSTEMATICALLY FARTHER NORTH THAN WITH THE UPPER LOW STARTINGON TUESDAY OVER THE OHIO/TENNESSEE VALLEY AND INCREASING ONWEDNESDAY INTO THURSDAY...ALTHOUGH THE DIFFERENCES BETWEEN THE 09ZSREF MEAN/06Z GEFS MEAN AND 00Z ECMWF ENSEMBLE MEAN WITH REGARD TOSPEED APPEARS PRETTY UNIFORM THROUGH WEDNESDAY AFTERNOON ANDEVENING WHEN THE SURFACE LOW IS ALONG THE EAST COAST.OVERNIGHT...THE 00Z UKMET TRENDED NORTH FROM EARLIER RUNS ANDAPPEARED TO BE VERY SIMILAR TO THE 00Z ECMWF...WHEREAS EARLIER ITWAS MORE OF A SOUTHERN OUTLIER. THE LAST FEW RUNS OF THE ECMWFHAVE INDICATED A TENDENCY FOR THE UPPER LOW TO BE SLIGHTLY FARTHERNORTH AND FASTER AS THE SYSTEM APPROACHES AND CROSSES THE EASTCOAST.  THE LAST 3 RUNS OF THE GFS THROUGH 6Z HAVE ALSO BEEN VERYSTABLE...WITH THE DIFFERENCES BETWEEN THE GFS/ECMWF ALSOCONTINUING.IN THE LAST COUPLE RUNS...THE 12Z NAM HAS TRENDED NORTHWARD ONCETHE CYCLONE IS EAST OF THE COAST...ALLOWING SNOW TO REACHNORTHWARD INTO LONG ISLAND AND SOUTHERN NEW ENGLAND...SOMETHINGTHAT THE RECENT RUNS OF THE GFS AND THE MOST RECENT RUN OF THEUKMET DOES...BUT THE 00Z ECMWF AND 00Z CANADIAN DO NOT.  THE NAM500 MB LOW IS CERTAINLY WITHIN THE REASONABLE SPREAD OF SOLUTIONSSHOWN BY THE ENSEMBLE MEANS BUT THE SURFACE LOW IS SLIGHTLYFARTHER NORTH OF THE OTHER SOLUTIONS AND CLOSER TO THE COAST BYWEDNESDAY AFTERNOON THAN THE EARLIER OPERATIONAL RUNS AS WELL ASTHE ENSEMBLE MEANS...EXCEPT FOR THE 09Z SREF ENSEMBLE MEAN WHERETHE SURFACE LOWS ARE NEARLY EXACT....UPPER LOW APPROACHING THE PACIFIC NORTHWEST/NORTHERN CALIFORNIABY TUESDAY TO WEDNESDAY...WHILE THE GENERAL STRUCTURE OF THE TROUGH IS MAINTAINED BY THE 00ZECMWF ENSEMBLE MEAN/06Z GEFS MEAN/ AND THE 09Z SREFMEAN THROUGHTHURSDAY...THERE ARE SOME DIFFERENCES LEADING UP TO THAT TIME. THE 12Z NAM APPEARS TO BE A LITTLE FASTER THAN THE MEANS ONWEDNESDAY WITH AN ODD 500 MB FEATURE OVER BRITISH COLUMBIAWEDNESDAY MORNING...BUT STARTS TO DEVELOP A CUTOFF LOW BY THURSDAYEVENING OVER NORTHERN CALIFORNIA THAT IS ALSO DEMONSTRATED BY THE00Z UKMET BUT THE OTHER MODELS APPEAR TO KEEP THE TROUGH AN OPENSYSTEM....UPPER TROUGH ORGANIZING OVER ONTARIO ON WEDNESDAY AND MOVINGTOWARD THE UPPER GREAT LAKES BY EARLY THURSDAY...THE OVERNIGHT ENSEMBLE MEANS SHOW AN AMPLIFYING TROUGH NORTH OFMINNESOTA BY EARLY WEDNESDAY THAT MAINTAINS ITSELF THROUGHWEDNESDAY EVENING.  HOWEVER...THE 00Z ECMWF ENSEMBLE MEANSMAINTAIN THE SYSTEM INTO THURSDAY WHERE THE SREF/GEFS DO NOT. THE00Z ECMWF AND THE 06Z GFS ALSO MAINTAIN THE SYSTEM THROUGHOUT THEFORECAST BUT THE 12Z NAM MOSTLY LOSES THE FEATURE BY THURSDAYMORNING....MODEL TREND GRAPHICS AT www.hpc.ncep.noaa.gov/html/model2.shtml...500 MB FORECASTS AT www.hpc.ncep.noaa.gov/h5pref/h5pref.shtmlKOCIN
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weathafella

weathafella

Posted
Posted

I looked at the BUFKIT sounding...most of the QPF falls as rain.  Now it certainly could be not cooling the boundary layer enough...but that is what it shows.

Well I just did the rough cut and looked at surface, H85, and MAV/MEX snow numbers which are 6 and 4 respectively.

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SR Airglow

SR Airglow

Posted
Posted

Verbatim probably, but these diagrams are known for making snow falling when surface is above 32 sleet or ZR, so most of the 1.8 which it says is sleet probably is a 33/34 degree snow.

-skisheep

Just throwing it out there, the gfs verbatim is mostly rain in Boston.

prec.png

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Diego

Diego

Posted
Posted

Walt Drag

DRAG SPECIAL 12 PM AFD!!!

**POWERFUL SLOW SEAWARD MOVING COASTAL STORM IS THE PRIMARY INFLUENCE ON OUR WEATHER THE FIRST HALF OF THIS PERIOD**

THE HAZARDOUS WEATHER OUTLOOK HAS BEEN UPDATED WITH SOME OF OUR INTENT AND FORECAST UNCERTAINTIES. WE'LL UPDATE THAT PRODUCT AGAIN AT 330 PM.

THIS AFD PRODUCT WILL UPDATE AGAIN BETWEEN 330 PM AND 4 PM AS TIME AVAILS.

IF WE ISSUE WATCHES...THEY WILL POST BY 330 PM.

500 MB: A STRENGTHENING CLOSED LOW SHORT WAVE TUE EVENING IN CENTERED OVER SOUTHERN ILLINOIS MOVES TO NEAR NORFOLK VIRGINIA MIDDAY WEDNESDAY THEN SLOWLY NORTHEASTWARD TO NEAR THE BENCHMARK OF 40N/70W MIDDAY THURSDAY. THEREAFTER...IT WEAKENS SLOWLY SOUTHEASTWARD WITH RIDGING OVER THE MID ATLANTIC STATES FRIDAY AND SATURDAY. COMPLICATIONS IN THE FLOW PATTERN DEVELOPS SUNDAY OVER THE NORTHEASTERN UNITED STATES WITH THE 00Z/4 ECMWF TRYING TO CUT A STRONG SHORTWAVE SOUTHEASTWARD THROUGH NEW ENGLAND. HOWEVER...IT ALL SMOOTHS OUT EARLY NEXT WEEK AS ANOTHER CLOSED LOW SHORT WAVE MOVES EAST FROM THE PLAINS STATES.

HAZARDS:

TO PREFACE THE DIRECTION WE ARE GOING... THE ECMWF HAS GENERALLY NOT BE STELLAR INSIDE OF DAY 5...SINCE THE SANDY EVENT FOR OUR AREA... AND IN MY OPINION...AT LEAST FOR THIS AREA...THE GFS AND ITS ENSEMBLES AS WELL AS THE SREF ARE BETTER PREDICTORS FOR OUR WEATHER. THAT SAID... I AM EXPECTING THE ECMWF TO TREND NORTH IN FUTURE CYCLES AND COME INTO BETTER AGREEMENT WITH THE GFS REGARDING WHAT SHOULD BE A POWERFUL COASTAL STORM FOR OUR AREA AND the FORTUNE THAT ITS NOT STALLING A LITTLE CLOSER TO OUR COAST. THE 12Z UKMET HAS EDGED NORTH.

COASTAL FLOOD WATCH PROBABLE WEDNESDAY INTO THURSDAY MORNING. CERTAINLY MINOR COASTAL FLOODING WILL OCCUR WITH A NORTHEAST SWELL WIND WAVE OF AT LEAST 10 TO 15 FEET. MORE DETAILS ARE IN THE TIDE SECTION.

HIGH WIND: DATA INCONSISTENTLY POINTS TO BOUNDARY LAYER WINDS AT TIMES EXCEEDING 40 KNOTS WEDNESDAY MIDDAY THROUGH WEDNESDAY NIGHT ALONG THE COASTS...MODELS FOCUSING ON DIFFERENT AREAS. EITHER VIA SUSTAINED (35 KTS) OR GUST (50KTS) WE THINK HIGH WIND HAS A GOOD CHANCE OF VERIFYING FOR A SHORT TIME WEDNESDAY.

Good pull Ginxy.

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Typhoon Tip

Typhoon Tip

Posted
Posted

I really find it hard to believe walt thinks the GFS has been better than the Euro all the way from Sandy to today.

 

 

He's right - people are forgetting the 40 days prior to the Blizzard that the Euro kept spinning up phantom over-amplified middle range events, where the GFS kept them flat and progressive and won that battle the majority of times.

 

The Euro scored better for the blizzard, granted - and that unfortunately is all people are remembering, skewing the reality of what the Euro vs GFS has mean up in this part of the country.   The Euro just blew it on the thermal field last week on that event, too, and though the GFS wasn't much better, one cannot fairly toss one puke performer in lieu of another.  

 

This may not be true on the hemispheric scale, and probably is not - it won't show at any verification scores, which integrate the whole system.  The Euro has proven with hefty data sets that it is the better performer over the long haul, and probably at some point it will do better locally; but during the intra-cold season times spans it was dubious.   

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OSUmetstud

OSUmetstud

Posted
Posted

He's right - people are forgetting the 40 days prior to the Blizzard that the Euro kept spinning up phantom over-amplified middle range events, where the GFS kept them flat and progressive and won that battle the majority of times.

 

The Euro scored better for the blizzard, granted - and that unfortunately is all people are remembering, skewing the reality of what the Euro vs GFS has mean up in this part of the country.   The Euro just blew it on the thermal field last week on that event, too, and though the GFS wasn't much better, one cannot fairly toss one puke performer in lieu of another.  

 

This may not be true on the hemispheric scale, and probably is not - it won't show at any verification scores, which integrate the whole system.  

I think most of those overamplified solutions were just outside of 5 days.  But there were a couple before that.  A couple overamped model runs does not make months of verification...even for a regional area.  I'd bet dollars to donuts that the Euro has better scores since Sandy in just about everywhere in the east.

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