ATL: IRENE - Models

[Ivanhater]

Well the HPC discussions highlights what I have been trying to say all day about the 12z model guidance


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

[stormhunter7]

recon is in the invest 97L and there doesnt appear to be any sign of a closed low... still moving to fast to the west!

[Sambucol]

Well the HPC discussions highlights what I have been trying to say all day about the 12z model guidance


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

What does that mean in terms of a potential track?

[Ivanhater]

HPC

FOR
NOW...WE HAVE USED THE LATEST COORDINATION POINTS AGREED UPON FROM
THE NHC AND EXTRAPOLATE ONE DAY FORWARD FOR THE NEW DAY 7 POINT.
THIS WILL PLACE IT OFF THE W COAST OF FL IN THE EASTERN GULF ON
SATURDAY....TO THE LEFT OF THE 12Z ECMWF/GFS POSITIONS.....

[Ivanhater]

Well the HPC discussions highlights what I have been trying to say all day about the 12z model guidance


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

What does that mean in terms of a potential track?

The torugh lifts out faster and the ridge builds quicker over it resulting in the system stalling getting trapped like the CMC and UKMET show..12z GFS was very close to this scenario as well.

[lonelymike]

MODELS DEPICT A SLOWLY EVOLVING LONGWAVE PATTERN OVER NORTH
AMERICA DURING THE UPCOMING MEDIUM RANGE PERIOD. AN UNUSUALLY
STRONG MID LEVEL HEIGHT ANOMALY WILL REMAIN NEARLY STATIONARY OVER
THE DAVIS STRAIT AND GREENLAND...FAVORING BROAD UPPER TROUGHS FROM
HUDSON BAY SOUTHWARD TO THE GREAT LAKES...AND FROM ALASKA ACROSS
THE NORTHEAST PACIFIC. IN BETWEEN...A FLAT RIDGE WILL DRIFT EWD
FROM THE PACIFIC NW TO MT BY THE END OF THE PERIOD. THE LONGWAVE
PATTERN IS SLIGHTLY PROGRESSIVE ABOVE LATITUDE 40N BUT STATIONARY
S OF THAT LATITUDE. DAY-TO-DAY DIFFERENCES ARE AVERAGE STARTING
DAY 3/TUE...BUT QUICKLY BECOME LARGE VICINITY OF THE STRONG AND
COMPLEX UPPER TROUGH OVER THE GULF OF ALASKA. THEY ALSO BECOME
LARGE IN THE CARIBBEAN SEA/GULF OF MEXICO DUE TO INCREASINGLY
DIFFERENT TRACK FORECASTS FOR THE TROPICAL WAVE NOW NEARING THE
LEEWARD ISLANDS. TO ADDRESS THESE INCREASINGLY LARGE
DIFFERENCES...WE USED A BLEND OF ECMWF/GEFS MEAN/ECMWF MEAN FOR
DAYS 3-7. THIS GAVE ONLY SLIGHTLY DIFFERENT RESULTS THAN THE BLEND
USED IN THE PRELIMS. FINAL GRAPHICS WERE LEFT UNCHANGED FROM THE
UPDATED PRELIM.

00Z/20 MODELS HAD TRENDED SLIGHTLY TO THE RIGHT OF PRIOR FORECASTS
WITH THE TROPICAL WAVE NEARING THE LEEWARD ISLANDS WITH THE 00Z
OPERATIONAL ECMWF CLOSEST TO THE DETERMINISTIC CONSENSUS AND
GLOBAL ENSEMBLE MEANS. 12Z MODELS DETERMINISTIC MODELS RANGE FROM
TRACKING THE SYS ON THE LEFT SIDE OF THE ENVELOPE INTO THE GULF OF
MEXICO AS PER THE CANADIAN/UKMET...TO THE RIGHT SIDE OF THE
ENVELOPE ALONG THE E COAST OF FL AS PER THE ECMWF/UKMET. FOR
NOW...WE HAVE USED THE LATEST COORDINATION POINTS AGREED UPON FROM
THE NHC AND EXTRAPOLATE ONE DAY FORWARD FOR THE NEW DAY 7 POINT.
THIS WILL PLACE IT OFF THE W COAST OF FL IN THE EASTERN GULF ON
SATURDAY....TO THE LEFT OF THE 12Z ECMWF/GFS POSITIONS.

NEW 00Z/20 ENSEMBLE SPAGHETTI PLOTS SHOWED THE DETERMINISTIC GFS
GETTING ON THE FAR RIGHT OF THE ENVELOPE OF SOLUTIONS WITH THE
TROPICAL SYS VICINITY OF FL BY NEXT WEEKEND. THE 06Z/20 GFS
BACKED OFF FOR NEXT SAT ON BEING S FAR N WITH IT. THE
DETERMINISTIC ECMWF CLUSTERS WELL WITH ITS OWN ENSEMBLE MEMBERS
AND EVEN SOME GEFS ENSEMBLE MEMBERS.


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

FLOOD




--------------------------------------------------------------------------------

[weatherguy2]

Yeah, likely not building a ridge back quite fast enough on the GFS and ECMWF, compared to UKMET and CMC.
And the mountains of Cuba and Haiti could keep it from getting too strong, thus even making it a tad farther west.

[KWT]

HPC

FOR
NOW...WE HAVE USED THE LATEST COORDINATION POINTS AGREED UPON FROM
THE NHC AND EXTRAPOLATE ONE DAY FORWARD FOR THE NEW DAY 7 POINT.
THIS WILL PLACE IT OFF THE W COAST OF FL IN THE EASTERN GULF ON
SATURDAY....TO THE LEFT OF THE 12Z ECMWF/GFS POSITIONS.....

Very interesting, judging by the trend of the models this season of models being a little too far east at times and the HPC/NHC seem to be taking notice of that by going abit further west probably due to the weight of the ensembles.

deltadog03, agreed, normally they do tend to shift westwards, at least a little in these borderline set-ups when you have a retreating weakness...good to see you back by the way!

[CYCLONE MIKE]

Well the HPC discussions highlights what I have been trying to say all day about the 12z model guidance


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

Preach to them Michael. Eventually they will see the light and listen to what you have ben trying to say all day. DeltaDog, Rock and I have been hearing you loud and clear.

[ROCK]

Well the HPC discussions highlights what I have been trying to say all day about the 12z model guidance


THE NEW 12Z GFS FOLLOWS ITS 00Z CONTINUITY REASONABLY WELL THRU
DAY 5 ON ALL THE MAIN FEATURES.
WE SEE BIGGER CHANGES FOR DAYS 6-7 AS TIMING/AMPLITUDE DIFFERENCES
CROP UP ACROSS CANADA. THESE CHANGES WOULD REMOVE THE POLAR
WESTERLIES ACROSS SRN CANADA EVEN FARTHER AWAY FROM HAVING ANY
INFLUENCE ON THE TRACK OF THE TROPICAL SYS THREATENING THE SERN
CONUS. IN FACT ALL THE 12Z DETERMINISTIC MODELS KEEP THE POLAR
WESTERLIES FAR ENOUGH N ACROSS SRN CANADA THAT AFTER A PINCH OF
ENERGY DROPS S INTO THE OH VLY THE FIRST PART OF THE MEDIUM RANGE
PERIOD...THERE SHOULD BE MINIMAL...IF ANY...INTERACTION OF ANY SE
CONUS TROPICAL SYS LATE NEXT WEEK WITH THE POLAR WESTERLIES.

Preach to them Michael. Eventually they will see the light and listen to what you have ben trying to say all day. DeltaDog, Rock and I have been hearing you loud and clear.

you can only say it so many times...

[gatorcane]

TVCN track (grey) into SE Florida (even with the left-biased UKMET).

We know the NHC likes to follow that for their track.

A track into the SE Gom would definitely be left of the consensus by a good bit.

I still would lean on the ECMWF for the synoptics in the 5 day range....and it has proven it is better than the GFS, CMC, or UKMET in forecasting strengths of ridges and troughs (though the GFS is in line with the ECMWF). I say that is some consensus right now at least with those two models!

[KWT]

Very close to the ECM actually, the only difference is it gains more of a NNW compared to the NW track the TVCN goes on.

Most models take the route of most disruption for a tropical cyclone...but wouldn't take much adjustment from the models at this stage to take a path over water for most of the time.

[Ivanhater]

Look at the angle Gator...more NW then north at the end...the angle on the models is trending more west instead of curving faster to the north.

[KWT]

Yeah I noticed that Ivanhater, mind you a further west motion may not be a bad thing if that means it spends more time over Cuba weakening...

funnily enough the ECM is both further west upto 120hrs then further east afterwards...probably suggesting its forecasting a slightly stronger upper trough on its 12z run, which would be a BAD thing for E.Florida and probably GA/SC.

[StarmanHDB]

HPC

FOR
NOW...WE HAVE USED THE LATEST COORDINATION POINTS AGREED UPON FROM
THE NHC AND EXTRAPOLATE ONE DAY FORWARD FOR THE NEW DAY 7 POINT.
THIS WILL PLACE IT OFF THE W COAST OF FL IN THE EASTERN GULF ON
SATURDAY....TO THE LEFT OF THE 12Z ECMWF/GFS POSITIONS.....

Sounds interesting, but living in South Florida, obviously I'm concerned as to what this storm will do prior to a possible eastern GOM/west coast Florida landfall. Will it stay over the Florida Straits, plow through the Florida Keys, or pull a Katrina and roll through South Florida first? Fun times ahead, eh?

[ronjon]

Look at the angle Gator...more NW then north at the end...the angle on the models is trending more west instead of curving faster to the north.

Yeah its getting that classic "rounding" the subtropical ridge track - all depends on the ridge strength and axis latitude.

[Rgv20]

As I expected the 12zECMWF Ensembles are further west than the operational run. The Ensembles call for a track just to the west of Florida.

12zECMWF Ensembles forecast valid for 168hrs.

[KWT]

Which is pretty much where the HPC/NHC agreed track is as well reading between the lines.

Also note how strong the reflection is at that point, for the ensembles thats quite impressive at 168hrs out!

[cpdaman]

As I expected the 12zECMWF Ensembles are further west than the operational run. The Ensembles call for a track just to the west of Florida.

12zECMWF Ensembles forecast valid for 168hrs.

could add a image of the 144hr ecm ensemble mean pleassssee

[gatorcane]

18Z NAM 84 hours: