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EPAC Tropical Action 2012


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Hater...:P

HPC:

WRN NORTH AMERICAN HEMISPHERE TROPICS CONT TO BE BASICALLY

INACTIVE AT THIS TIME AS SEEN BY CHI VELOCITY POTENTIAL ANOMALIES

INDICATING UNFAVORABLE CONDITIONS. THIS MAY WELL CHANGE IN A WEEK

TO 10 DAYS AS INDICES SHOW AN INCREASE AS THE SOUTH AMERICAN

MONSOON ACTIVITY SHIFTS NORTHWEST INTO CENTRAL AMERICA AND

SOUTHERN MEXICO WITH BETTER CONDITIONS OVER THE WRN CARRIBEAN AND

ESPECIALLY THE TROPICAL EAST PACIFIC WHICH IS TYPICAL JUNE

CLIMATOLOGY. LONGER TERM RUNS OF GFS CONT TO SHOW AN INCREASE OF

DEEP SERLY FLOW THRU THE WRN CARRIBEAN INTO THE GULF OF MEXICO

WITH A RETURN OF MORE WESTERLY FLOW ALONG 10N AT H850 PRODUCING A

MORE LARGE SCALE CYCLONIC FLOW PATTERN ALSO INCREASING MORE

FAVORABLE LONGER TERM TROPICAL EAST PAC CONDITIONS.

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Guidance continues to advertise TC genesis near the Gulf of Tehuantepec in the 7-10 day range. There are indications that the MJO will be more favorable in this time frame and the HPC suggests Chi forecast are conducive for tropical formation during the end of June as well...

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Nice writeup this morning:...;)

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

352 AM EDT FRI JUN 08 2012

VALID 12Z TUE JUN 12 2012 - 12Z FRI JUN 15 2012

POSITIVE 500 HPA HEIGHT ANOMALIES ACROSS NORTHWEST CANADA WITH

BUILDING RIDGING ACROSS THE NORTHEAST PACIFIC ARE EXPECTED TO LEAD

TO RENEWED WESTERN TROUGHING LATE NEXT WEEK. DOWNSTREAM RIDGING

IS EXPECTED TO BUILD ACROSS THE MIDWEST WITH RESIDUAL ENERGY ALOFT

LINGERING OFFSHORE THE EAST COAST. A FAVORABLY-PLACED SUBTROPICAL

RIDGE ACROSS NORTHWEST MEXICO SHOULD LEAD TO A COUPLE TROPICAL

CYCLONE ATTEMPTS ACROSS THE NORTHEAST PACIFIC DURING THE NEXT

WEEK...AS ADVERTISED BY THE SUNY-ALBANY/ROUNDY TROPICAL CYCLONE

PROBABILITIES DURING LATE MAY. FOR THE MOST PART...THE

DETERMINISTIC/ENSEMBLE GUIDANCE SHARE THESE IDEAS. THE 00Z

CANADIAN WAS A STRONG OUTLIER IN THE WESTERN ATLANTIC...WHILE THE

00Z GFS SHOWED THE WEAKEST SHORTWAVE TROUGH IN THIS AREA. TO

ACCOUNT FOR THE UNCERTAINTY...USED A 40/30/30 COMPROMISE OF THE

00Z UKMET/00Z GFS/00Z ECMWF THROUGH WEDNESDAY BEFORE USING A 50/50

BLEND OF THE 00Z GFS/00Z ECMWF THEREAFTER TO DEAL WITH

UNCERTAINTIES NEAR THE EAST COAST LATE NEXT WEEK.

ROTH

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Another pretty poorly forecasted genesis event in the EPAC is underway. The GFS has this system dissipating almost immediately which isn't going to happen, while the ECMWF shows the system battling moderate to strong Easterly shear before it fades away post 36 hours. I think the global models are probably underestimating the potential max intensity with this system, and SHIPS/LGEM is a good lowball estimate for the system reaching moderate to strong TS strength in 48 hours.

Notice how the development of 93E seems to be closely tied with the passage of a pretty potent Kelvin Wave. The highest VP anomalies associated with the kelvin wave that seems to have just passed the system, and notice how the upper level winds have quickly shifted from strong westerly to weak easterly across portions of the Northeast Pacific in recent days.

EDIT: Maybe I spoke too soon... doesn't look nearly as well organized as IR was depicting this morning. Still plenty of time for it to get its act together but the low/mid level centers are clearly disjointed at this time.

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Another pretty poorly forecasted genesis event in the EPAC is underway. The GFS has this system dissipating almost immediately which isn't going to happen, while the ECMWF shows the system battling moderate to strong Easterly shear before it fades away post 36 hours. I think the global models are probably underestimating the potential max intensity with this system, and SHIPS/LGEM is a good lowball estimate for the system reaching moderate to strong TS strength in 48 hours.

Notice how the development of 93E seems to be closely tied with the passage of a pretty potent Kelvin Wave. The highest VP anomalies associated with the kelvin wave that seems to have just passed the system, and notice how the upper level winds have quickly shifted from strong westerly to weak easterly across portions of the Northeast Pacific in recent days.

EDIT: Maybe I spoke too soon... doesn't look nearly as well organized as IR was depicting this morning. Still plenty of time for it to get its act together but the low/mid level centers are clearly disjointed at this time.

looks like the ECMWF had the right idea all along. Its not completely dead yet, but its having exceptional difficulty aligning the low/mid level centers against easterly shear. The wind anomalies with the Kelvin wave aren't actually helping because the upper level easterlies have continued to increase as the low-level flow is moving much more slowly (partially due to a mature WWB in the anomaly field).

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Well the 12Z Euro is certainly bullish with 94E.

988mb direct hit to Huatulco/Puerto Angel. This could be a legitimate threat because conditions might be pretty good, with strong poleward outflow evacuation and especially if the disturbance to the west can get out of the way, and if there's a quick structure organization we could see RI before landfall (intensifying at landfall)...the GFS has a bit farther east, with a hit in the Gulf of Tehuantepec.

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94E is now a cherry. Since we are having ongoing discussions in both Basins, I suspect the pattern that is unfolding is similar to what we saw in 1989. Hurricane Cosme made landfall near the Gulf of Tehuantepec in the EPAC and left over energy developed into what would become Tropical Storm Allison in the Western Gulf in late June of that year. The pattern does suggest increased moisture in the Western Caribbean/Western Gulf as the monsoonal trough lifts N and multiple areas of vorticity develop within the monsoonal gyre of a broad area of low pressure near the Bay of Campeche. Forecaster Roth covers this in the HPC overnight extended forecast...

ELSEWHERE...A RETROGRADING REX BLOCK MOVED FROM THE 60TH PARALLEL

TOWARDS THE EAST COAST...WITH ITS SOUTHERN MEMBER DRAGGING A COLD

FRONT THROUGH NORTHWEST CUBA...SOMEWHAT UNUSUAL FOR MID TO LATE

JUNE. DUE TO THE RETROGRADING UPPER LOW BETWEEN BERMUDA AND THE

SOUTHEAST...DISTURBED WEATHER/A BROAD AREA OF LOW PRESSURE IS

EXPECTED ACROSS THE WESTERN CARIBBEAN...WHICH MAY DRIFT NORTHWEST

TOWARDS THE YUCATAN CHANNEL BY NEXT WEDNESDAY. GENERAL RIDGING

ACROSS NORTHWEST MEXICO AND INCREASINGLY ACROSS THE SOUTHWEST

FAVORS DISTURBED WEATHER WITHIN THE TROPICAL EASTERN PACIFIC...AND

THE 12Z GLOBAL ENSEMBLE GUIDANCE SHOWS TWO PROSPECTS FOR

DEVELOPMENT OVER THE NEXT WEEK IN THIS REGION. SATURDAY SEEMS TO

BEST CHANCE FOR THUNDERSTORMS ACROSS ARID NEW MEXICO...BUT EVEN

THEN THEY SHOULD BE SCATTERED TO WIDELY SCATTERED IN NATURE AND

COULD DO MORE HARM THAN GOOD.

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It looks like we may have some RECON for 94E...

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

0930 AM EDT WED JUN 132012

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID 14/1100Z TO 15/1100Z JUN 2012

TCPOD NUMBER.....12-026

I. ATLANTIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. SUCCEEDING DAY OUTLOOK: FIX OF A POSSIBLE DEVELOPING

HURRICANE AT 15/1800Z NEAR 13.5N 95.5W

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My hunch is that this system is going to end up fighting easterly shear as the upper level easterly flow increases on the backside of a CCKW. On the flip side, the system is situated in a high SST and deep moisture environment, so easterly shear alone might not be enough to prevent development like we saw with 93E.

21chu79.png

EDIT: I meant upper level easterlies, not westerlies.

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