Global model runs discussion

[cycloneye]

What we need IMO is to have a focus as invest and we will have a place to watch an area in particular.

[KUEFC]

How can they invest an area if its not an area of low pressure? Also is it totally impossible for models to be wrong?

[LarryWx]

Non-GFS models have still yet to be all that threatening with regard to any potential SE US TC threat early next week. The Euro runs have been pretty weak with any landfalls from their Gulf solutions. However, as of the Thu 12Z GFS, the last four GFS runs have shown a more organized TS landfalling anywhere from NE FL to CHS on Tuesday 10/11. That is pretty consistent and it is only five days away (i.e., somewhat predictable):

18Z Wed: Brunswick 1000 mb
00Z Thu: St. Augustine 1005 mb
06Z Thu: Charleston 1003 mb
12Z Thu: Brunswick 1003 mb

Edit: Looking more closely at these GFS runs, there is now a weak warm/tropical piece of energy located near Hispaniola that moves WNW to the SE Bahamas. Meanwhile, another parcel of energy/moisture (cold...note the falling 850's in this area), now north of 32 N, is pushed south over the next two days by the rather strong and deep high building over the NE US. Once these two pieces of energy/moisture collide over the central Bahamas, a more defined surface low forms, subsequently strengthens. From there, the low moves mainly NNW and brings warmer air with it, which is indicative of a system quickly becoming tropical (check out the warming 850 temp.'s and that the warmest 850's move with this low). That is my take as to what the GFS is doing. Any other opinions?

[AdamFirst]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
935 AM EDT THU OCT 6 2011

.DISCUSSION...

...POTENTIAL FOR A HEAVY RAINFALL EVENT ALONG THE COAST LATE WEEK
INTO THE WEEKEND...

FRI-SAT...TROUGH ALOFT FORECAST TO CUT OFF VICINITY OF THE
FLORIDA PENINSULA AND EASTERN GULF. RATHER STRONG SURFACE HIGH
PRESSURE ALONG THE EASTERN SEABOARD WILL TIGHTEN THE GRADIENT AND
INCREASE MOISTURE CONVERGENCE. THE GFS HAS BEEN SHOWING A HINT OF
A WEAK LOW LEVEL BOUNDARY WORKING DOWN THE COAST FRI NIGHT INTO
SAT. THIS COULD BE A KEY PLAYER IN FOCUSING HEAVY RAINFALL.

IT IS STILL TOO FAR OUT TO PINPOINT WHERE THIS WILL OCCUR...BUT
WITH 25-30 KNOT SURFACE TO 850MB WINDS...THERE IS A POTENTIAL FOR
TRAINING ECHOES TO PRODUCE A SIGNIFICANT RAIN EVENT...ESPECIALLY
ALONG THE COAST. HAVE INDICATED IN QPF GRIDS THAT THERE IS SOME
POTENTIAL FOR HEAVY RAINS ALONG THE COAST.

WE WILL LIKELY NEED TO CONSIDER A FLOOD WATCH AS RAINFALL AMOUNTS
IN THESE SITUATIONS CAN BE EXCESSIVE...ESPECIALLY SINCE THE
ATLANTIC WATERS REMAIN VERY WARM AND THE EVENT SHOULD LAST FOR
SEVERAL DAYS.

THERE MAY BE SOME SIMILARITIES TO A MAY 2009 EVENT IN WHICH THERE
WAS A ONE-TWO PUNCH FROM FRONTAL CONVERGENCE THEN A SUBTROPICAL
LOW. A SUMMARY OF THAT EVENT IS AVAILABLE AT:
http://WWW.SRH.NOAA.GOV/MLB/?N=052309

SUN THROUGH EARLY NEXT WEEK...THE GFS CONTINUES RUN TO RUN
INCONSISTENCIES WITH RESPECT TO HYBRID (SUBTROPICAL) LOW LIFTING
NORTHWARD. THE 00Z RUN SHOWED MOVING ACROSS THE BAHAMAS TOWARDS
NORTHEAST FLORIDA. THE ECMWF HAS HAD BETTER CONSISTENCY AND HPC
PROGS HAVE FAVORED ITS SOLUTION WITH THE LOW CENTER MOVING
NORTHWARD IN THE EASTERN GULF. HAVE MADE LITTLE CHANGE TO THE
PREVIOUS WIND GRIDS WHICH WERE FOLLOWING CLOSE TO THE ECMWF
SOLUTION.

BOTH TRACKS WOULD BRING HEAVY RAIN...GALE FORCE WINDS AND BEACH
EROSION. THE GULF TRACK WOULD ALSO POSE A THREAT FOR ISOLATED
TORNADOES.

THE EXACT TIMING FOR THIS EVENT IS STILL UNCERTAIN DUE TO MODEL
INCONSISTENCIES...BUT GENERALLY THINK THAT THE INITIAL LOW
FORMATION...ABOUT SUNDAY...WILL ACT TO ENHANCE THE HEAVY RAINFALL
CHANCES ONGOING FROM SAT. AS THE LOW LIFTS CLOSER TO FLORIDA LATER
SUNDAY INTO MONDAY...LOW LEVEL SHEAR WOULD INCREASE AND BRING THE
THREAT FOR ISOLATED TORNADOES.

[cycloneye]

From Dr Jeff Masters:

A large low pressure system with heavy rain is expected to develop over Cuba and South Florida on Saturday. The counter-clockwise flow around this low will bring strong winds and heavy rains to much of the Florida coast on Saturday, and these conditions will spread northwards to Georgia by Sunday and South Carolina by Monday. The storm may evolve into a subtropical storm that gets a name by Monday or Tuesday, but the potential location of such a storm is still murky. The extended forecast discussion from NOAA's Hydrometeorological Prediction Center favors a more westerly location, in the eastern Gulf of Mexico, as predicted by the ECMWF model. The GFS model, which puts the storm's center east of Florida, is pushing the weather system that will spawn the subtropical storm too fast to the east. In any case, the exact center location of the storm will not matter that much, since this will be a large, diffuse system that will bring strong winds and heavy rains to a large area of the Southeast U.S. coast, regardless of the exact center location. Portions of the coastal waters from Southeast Louisiana to the Florida Panhandle, as well as from Northeast Florida to South Carolina, are likely to experience sustained winds of 35 - 45 mph Monday and Tuesday. Since the storm is going to get its start as a cold-cored upper-level low pressure system with some dry air aloft, it will probably start out subtropical, with a large band of heavy rain developing well north of the center. Subtropical storms cannot intensify quickly, due to their lack of an organized inner core, and I'm not concerned at present about this storm potentially becoming a hurricane.

Rainfall forecast for the 5-day period ending at 8 am EDT Tuesday, October 11, 2011. The storm system affecting Florida this weekend is expected to bring up to 7 inches of rain along the coast. Heavy rains associated with a strong trough of low pressure are also expected to dump 4 - 6 inches of rain over drought-stricken areas of Texas, Oklahoma, and Kansas.

[LarryWx]

Folks,
The 12Z Euro is sticking to its E GOM surface low solution, which it has had for at least three runs in a row. So, we have the GFS' last four SE US coast landfalls vs. the Euro's last three GOM solutions. Which will verify to be closer? Should we go with King Euro? Any bets and why?

[maxx9512]

I know this is probably the wrong forum but I have question if someone could give a brief answer.
What is the difference between the ECMWF-ensmen and the ECMWF-oper? Am I correct in that the ecmwf-oper is the mix
of models, but I don't know know what is the -mean model is.
Also should I give one more weight than the other, in other words should I favor one over the other?
Thanks so much in advance for any quick explanation.

[AJC3]

I know this is probably the wrong forum but I have question if someone could give a brief answer.
What is the difference between the ECMWF-ensmen and the ECMWF-oper? Am I correct in that the ecmwf-oper is the mix
of models, but I don't know know what is the -mean model is.
Also should I give one more weight than the other, in other words should I favor one over the other?
Thanks so much in advance for any quick explanation.

The ECMWF-ensmean is actually the mean of all the ensemble runs, while the ECMWF-oper is the operational (single) run of the model.

[wxman57]

I know this is probably the wrong forum but I have question if someone could give a brief answer.
What is the difference between the ECMWF-ensmen and the ECMWF-oper? Am I correct in that the ecmwf-oper is the mix
of models, but I don't know know what is the -mean model is.
Also should I give one more weight than the other, in other words should I favor one over the other?
Thanks so much in advance for any quick explanation.

The ensemble run is a group (an ensemble) of ECMWF runs with slightly different initializations, which will often yield different solutions. The operational run is just a single run of the ECMWF with one initialization.

[wxman57]

I'm in agreement with Jeff Masters on the development of this system. Probably sheared and subtropical to start with at least. May not have a lot of time over water to transition to tropical and intensify. Mostly a rain-maker rather than a wind event, probably. Hurricane chances would be low. I'm not sure I buy the GFS solution of formation in the SW Bahamas yet, but I can't rule it out.

On the MIMIC-TPW loop take note of the wave passing the DR/Haiti now. That's the wave which spawned Philippe:
http://tropic.ssec.wisc.edu/real-time/m ... /main.html The main vorticity is moving right over the DR/Haiti now.

[cycloneye]

Latest 72 hour TAFB forecast.

[KUEFC]

I'm in agreement with Jeff Masters on the development of this system. Probably sheared and subtropical to start with at least. May not have a lot of time over water to transition to tropical and intensify. Mostly a rain-maker rather than a wind event, probably. Hurricane chances would be low. I'm not sure I buy the GFS solution of formation in the SW Bahamas yet, but I can't rule it out.

On the MIMIC-TPW loop take note of the wave passing the DR/Haiti now. That's the wave which spawned Philippe:
http://tropic.ssec.wisc.edu/real-time/m ... /main.html The main vorticity is moving right over the DR/Haiti now.

So you agree with ecmwf really?

[wxman57]

I'm in agreement with Jeff Masters on the development of this system. Probably sheared and subtropical to start with at least. May not have a lot of time over water to transition to tropical and intensify. Mostly a rain-maker rather than a wind event, probably. Hurricane chances would be low. I'm not sure I buy the GFS solution of formation in the SW Bahamas yet, but I can't rule it out.

On the MIMIC-TPW loop take note of the wave passing the DR/Haiti now. That's the wave which spawned Philippe:
http://tropic.ssec.wisc.edu/real-time/m ... /main.html The main vorticity is moving right over the DR/Haiti now.

So you agree with ecmwf really?

No. Jeff didn't say he bought the ECMWF, he said NOAA was following the ECMWF solution.

[KUEFC]

I'm in agreement with Jeff Masters on the development of this system. Probably sheared and subtropical to start with at least. May not have a lot of time over water to transition to tropical and intensify. Mostly a rain-maker rather than a wind event, probably. Hurricane chances would be low. I'm not sure I buy the GFS solution of formation in the SW Bahamas yet, but I can't rule it out.

On the MIMIC-TPW loop take note of the wave passing the DR/Haiti now. That's the wave which spawned Philippe:
http://tropic.ssec.wisc.edu/real-time/m ... /main.html The main vorticity is moving right over the DR/Haiti now.

So you agree with ecmwf really?

No. Jeff didn't say he bought the ECMWF, he said NOAA was following the ECMWF solution.

sorry my mistake, just with you saying you didnt really belive gfs solution at the min

[Downdraft]

The track will make a huge difference for Florida. Although this is largely a rainmaker the west solution increases the chance of severe weather, specifically tornadoes while the east solution does not.

[weatherwindow]

looking just a bit further forward than next wed... i found it interesting that the last fews runs of the globals, regardless of their near term solutions, leave a series of broad lows in the western and southwestern caribbean. given the strong mjo signal and the strengthening la nina, we may finally see a flurry of trackable classic october activity...going out with a bang so to speak. something to spark floridian interest again

[fci]

looking just a bit further forward than next wed... i found it interesting that the last fews runs of the globals, regardless of their near term solutions, leave a series of broad lows in the western and southwestern caribbean. given the strong mjo signal and the strengthening la nina, we may finally see a flurry of trackable classic october activity...going out with a bang so to speak. something to spark floridian interest again

Yes, the next few weeks represent the worrisome weeks for Florida for strikes from the Southwest or South.

[dizzyfish]

NWS Tampa has put all their eggs in the ECMWF basket....

.LONG TERM (SUNDAY NIGHT-THURSDAY)...ECMWF CONTINUES TO BE THE
PREFERRED MODEL IN THE EXTENDED PERIOD AS THE GFS REMAINS TOO FAR
EAST WITH SURFACE LOW DEVELOPMENT AND TRACK. STRONG SURFACE HIGH
PRESSURE WILL HOLD ALONG THE MID ATLANTIC COAST MONDAY WITH AN
AREA OF LOW PRESSURE DEVELOPING OVER THE SOUTHEAST GULF OF
MEXICO...MOST LIKELY A HYBRID TYPE STORM SYSTEM. TIGHT PRESSURE
GRADIENT BETWEEN THE HIGH TO THE NORTH AND LOW TO THE SOUTH WILL
ENHANCE WINDS OVER THE FORECAST AREA AND ADJACENT COASTAL WATERS.
HIGH DEGREE OF UNCERTAINTY REMAINS WITH EVOLUTION AND TRACK OF THE
AREA OF LOW PRESSURE...BUT DRY SLOT MAY DEVELOP EAST OF THE CENTER
WHICH COULD BE OVER WEST CENTRAL AND SOUTHWEST FLORIDA ON
MONDAY...WITH A CHANCE OF SHOWERS AND SLIGHT CHANCE OF
THUNDERSTORMS. AS THE SURFACE LOW TRACKS NORTH OVER THE EASTERN
GULF MONDAY NIGHT AND TUESDAY...INCREASING SOUTH TO SOUTHWEST FLOW
WILL ALLOW NUMEROUS SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP
OVER THE COASTAL WATERS WHICH WILL MOVE LOCALLY ONSHORE.
POSSIBILITY FOR TRAINING OF HEAVY RAIN BANDS WHICH COULD CAUSE
LOCALIZED FLOODING. SURFACE LOW EXPECTED TO MOVE TOWARDS THE BIG
BEND AREA LATE TUESDAY NIGHT WITH DECREASING CHANCE OF RAIN ACROSS
WEST CENTRAL AND SOUTHWEST FLORIDA ON WEDNESDAY. DEPENDING ON THE
STRENGTH OF THE SURFACE LOW...SOUTH TO SOUTHWEST WINDS OVER THE
EASTERN GULF WILL CAUSE WATER TO PILE UP CREATING A THREAT OF
COASTAL FLOODING. ALTHOUGH TIMING IS STILL VERY MUCH IN
DOUBT...ATTM IT APPEARS BEST CHANCE WILL BE TUESDAY AND TUESDAY
NIGHT. IN THE WAKE OF THIS STORM SYSTEM...A STRONG U/L DISTURBANCE
WILL APPROACH THE SOUTHEAST U.S. ON THURSDAY WITH CONTINUED
SOUTHWEST FLOW OFF THE GULF OF MEXICO AND A CHANCE OF SHOWERS AND
THUNDERSTORMS.

[cycloneye]

This GFS graphic is in the 10 day timeframe,not in 16 days,and it has continued to develop a Caribbean system with different tracks and intensities from run to run. This is the 06z run.



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[KUEFC]

Can the gfs be trusted as a long range model?