Global model runs discussion

[Hybridstorm_November2001]

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
330 PM EDT WED AUG 10 2011

VALID 12Z SAT AUG 13 2011 - 12Z WED AUG 17 2011

GENERALLY ABOVE NORMAL HEIGHTS AT HIGH LATITUDES AND A PERSISTENT
TROF ALONG 140 W FAVOR THE DOWNSTREAM WESTERLIES SAGGING S OF
NORMAL OVER THE ERN HALF OF THE LOWER 48. THE NEW 00Z/10 ENSEMBLE
SPAGHETTI PLOTS SUGGEST A HUNG BACK UPPER TROF OVER VA/THE
CAROLINAS DAYS 6-7. IF CORRECT...THIS SHARP TROF OR SHEAR AXIS
COULD INTERACT WITH TROPICAL ENERGY WELL OFF THE SOUTH ATLANTIC
COAST IN ABOUT A WEEK.

THE LONGWAVE FLOW PATTERN FEATURES AMPLIFIED TROUGHS ALONG BOTH
THE EAST AND WEST COASTS...WITH RIDGING IN BETWEEN...AND
SHORTWAVES ROUNDING THE WESTERN TROUGH INTO WESTERN/CENTRAL
CANADA. THE NEW 00Z/10 ECMWF ENSEMBLE MEAN HAS GOOD CONTINUITY
FROM ITS PREVIOUS 12Z MEAN....AND SUPPORTS THE SAME GENERAL IDEAS
AS THE CORRESPONDING GEFS MEANS. WHILE GUIDANCE AGREES ON THESE
LARGE SCALE IDEAS...THERE ARE THE USUAL DETAIL ISSUES WITH THE
STRENGTH AND TIMING OF VARIOUS SHORTWAVES...ESPECIALLY THOSE
ROUNDING/EJECTING FROM THE WEST COAST TROUGH. AFTER STAYING WITH
HPC CONTINUITY FOR DAYS 3-4...THE FINAL PROGS KEPT THE UPDATED
PRELIM IDEA OF MAKING THE 00/10 GEFS/ECENS MEANS THE LIONS SHARE
OF THE MODEL BLEND FOR DAYS 6-7. THIS HELPS SMOOTH OUT SHORTWAVE
DETAIL DIFFERENCES OVER THE NORTHWESTERN CONUS. THE COLD FRONT IN
THE SOUTHEAST WAS ADJUSTED FARTHER NORTH IN FL THAN THE EARLY
PRELIM FOR WED/DAY 7.

CONCERNING AN IN IMPORTANT SHORTWAVE TROF AMPLIFYING IN THE ERN
PORTION OF THE COUNTRY DAYS 3-5...THE NEW 12Z GFS HAS VERY GOOD
CONTINUITY THRU DAY 5...WITH THE 12Z AND 06Z GFS TRENDING FASTER
THAN 00Z CONTINUITY OFF THE ATLANTIC COAST FOR DAYS 6-7. THE
CANADIAN AND GFS ALSO LOOK GOOD HERE. THE 12Z CANADIAN CONTINUES
ON THE DEEP SIDE OF MODEL SOLUTIONS DAYS 4-5 OVER THE LOWER GREAT
LAKES AND MID ATLANTIC REGIONS. THE NEW 12Z ECMWF TRENDS A LITTLE
DEEPER AND SLOWER WITH THE SYSTEM AS IT APPROACHES THE EAST COAST
DAYS 5-6...MON/TUE. A BLEND OF 12Z MODELS WEIGHTED TOWARDS THE 12Z
GEFS MEAN IS THE PREFERRED SOLUTION HERE. THE GFS RUN TO RUN
CONTINUITY OFF THE W COAST APPEARS LESS RELIABLE...AND WE PREFER
MORE OF A ECMWF/ECMWF MEAN SOLUTION WHICH KEEPS MORE CYCLONIC
ENERGY FARTHER N IN THE GULF OF ALASKA THAN THE GFS. 12Z GFS/UKMET
SEEM TO BRING TOO MUCH HEIGHT FALL INTO THE NW STATES DAYS 5-6
COMPARED TO THE 00Z/10 ECMWF AND ITS ENSEMBLE MEAN. THE 12Z GEFS
MEAN WAS EARLIER PREFERRED HERE AS IT WAS CLOSEST TO THE THE
00Z/10 ECMWF AND ECENS MEAN SOLUTIONS. HOWEVER WIT THE NEW 12Z
ECMWF TRENDING CONSIDERABLY DEEPER DAYS 5-7 WIT THE TROF ALONG THE
WEST COAST STATES...THE GFS IDEA OF A DEEPER TROF THERE MIGHT BE
OK...ALBEIT WITH LOW CONFIDENCE IN THE EMBEDDED SHORTWAVES.


THE UNUSUALLY STRONG WEEKEND DYNAMICS FOR AUGUST OVER THE ERN
CONUS SHOULD PRODUCE A WIDESPREAD AREA OF SYNOPTIC SCALE MODERATE
TO HEAVY CONVECTIVE RAINFALL FROM THE APPALACHIANS EWD THRU THE
CAROLINAS THEN NORTHEASTWARDS UP THE EAST COAST STATES.


THE HEAT SHOULD BE CONSTRAINED TO THE SOUTHWEST...CENTRAL/SOUTHERN
ROCKIES...AND PLAINS. NORTHERN FLORIDA WILL EXPERIENCE AN
ATYPICAL SUMMER COLD FRONT....DRIVEN BY WELL BELOW NORMAL 500 HPA
ANOMALIES ACROSS THE CAROLINAS.

FLOOD


Source:

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

[xironman]

Your kind of setup, eh hybridstorm. I always liked HPC discussions done by Flood, the irony.

[Hybridstorm_November2001]

Your kind of setup, eh hybridstorm. I always liked HPC discussions done by Flood, the irony.

It more reminds me of what Floyd did to the Carolinas in 1999, actually. I hope we do not see a repeat for those in that region.

[South Texas Storms]

Very very true......the pattern like last season may not change.
I'm not complaining.

I made an earlier comment on another thread that a high should build in eventually preventing
all of these recurves, but I also said that last year and the pattern never changed, so what do I know .
For all I know, the pattern may never change this year, just like last year.....

I am....we are in a drought....lakes and rivers are drying up...any moisture in whatever form is needed....

True Rock. We need rain SO BADLY...

[Frank2]

The TX high has eliminated our easterlies because of the trough over Florida - we have either westerlies or light and variable winds, so anything forming to the east might (might) stay to the east...

[GCANE]

GFS is hinting something in the west Carib moving into the GOM at the end of its run.

Something to keep an eye on.


http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[dwsqos2]

It will be pretty boring if the 12Z gfs verifies.

[HurricaneFan]

Could it be that even though we are in neutral enso state,the atmosphere is still behaving like a La nina?(The CPC update is even down to -0.4C lately.)
And if so,doesn't La nina seasons tend to have more active Cape Verde Seasons,but tend to start later?

[weatherwindow]

with the dry air, sal and the unusual lack of instability(noted by wxman57), perhaps, we are instore for another weak CV season. Genesis may shift west and put the US coastline, particularly the southeast and Gulf, at inhanced risk. the forecast movement of the plains "death ridge" to the east coast during the last week of august may enhance the both "homegrown" genesis(southwest north altantic and caribbean basins) and the likelihood of short-fused westward tracks ala 2005. since we are just entering the beginning of the season peak, the hostility of the eastern and central tropical atlantic may ease. however, even if eastern MDR remains barren, 2005 has certainly taught us that a lack of a CV season doesnt mean season closed. Just shift your focus west and hang on for the ride.....rich

[ROCK]

the 18Z GFS was interesting with a major hurricane approaching the channel at 384hr.....yes I know la la land

[lonelymike]

Pretty strange this time of year a major hurricane is in "la-la land". Rock keep doing that raindance

[NDG]

Latest EUROSIP forecast shows that an active September and October in the tropical Atlantic's MDR is still possible, with lowering SPs lower than last months forecast for the same time period.

[cycloneye]

Did the 12z run of ECMWF had the same hurricane just north of PR that 00z had? I guess not,wow and another word incredible.

00z



12z

[weatherwindow]

luis...i agree..."WOW''...not a even fair weather cumulus on that 12Z euro...somewhat unusual for the euro to have that foolishness isnt it?.....a bit more stable yes?.....on another tack, perhaps, as i mentioned in an earlier post, the eastern MDR doesnt recover from its bout of anamalous stability, dry air, etc and the isle of enchantment will not be threatened this year...however, more likely the eastern atlantic gets over it and we have a CV season after all.....rich

[cycloneye]

luis...i agree..."WOW''...not a even fair weather cumulus on that 12Z euro...somewhat unusual for the euro to have that foolishness isnt it?.....a bit more stable yes?.....on another tack, perhaps, as i mentioned in an earlier post, the eastern MDR doesnt recover from its bout of anamalous stability, dry air, etc and the isle of enchantment will not be threatened this year...however, more likely the eastern atlantic gets over it and we have a CV season after all.....rich

Euro with this extravaganza between 12 hours has lost a bit of credibility in my book To regain credibility back,it will have to show at least 4 consecutive runs of something without dropping it.

[cycloneye]

IMO,the models will start to latch on more things in the next couple of weeks as the wet MJO is arriving into the Atlantic Basin.



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[HurricaneFan]

So could the La nina like atmosphere(even though we're still in neutral) be causing a late start to the Cape Verde Season in particular?
I've also heard that La nina seasons are affected by the MJO more(both negative and positive).

[Brent]

2nd GFS run in a row to have a major U.S. hit

[Stormcenter]

La la land. IMO

2nd GFS run in a row to have a major U.S. hit

[CaneCurious]

La la land. IMO

2nd GFS run in a row to have a major U.S. hit

I'm hoping its in la la land! Thats right at my front door.