2012 Atlantic Hurricane Season General Discussions

[gocuse22]

Models on board for possible development around the 17th-18th

[srainhoutx]

Models on board for possible development around the 17th-18th

The battle of the C's. Carlotta (EPAC) and a weaker sheared Chris (Bay of Campeche). These monsoonal troughs are difficult to forecast, but the EPAC would seem to be the best bet for now.

[srainhoutx]

The GFS and Euro are suggesting a broad area of disturbed weather in the Bay of Campeche in the 8-10 day time frame. Past experience suggest with monsoonal trough type systems, these are are slow developing storms...we will see...

[srainhoutx]

The HPC has introduced an area of broad low pressure in the Bay of Campeche next Monday...

[weatherguy425]

I nice messy tropical storm that moves WNW out of the Bay of Campeche would be wonderful, especially if it can cause the ridge to retrograde much further west and leave behind a nice moist flow off of the Gulf.

[srainhoutx]

HPC Morning update from Forecaster Roth:

THIS PATTERN FAVORS A LATE SEASON COLD FRONTAL PASSAGE THROUGH THE
FLORIDA PENINSULA AND FLORIDA STRAITS AS THE REX BLOCK
RETROGRADES. BETWEEN SUNDAY AND TUESDAY...A MID-LEVEL CYCLONE IS
EXPECTED TO PASS BETWEEN BERMUDA AND THE EAST COAST...FAVORING THE
DEVELOPMENT OF DISTURBED WEATHER/A BROAD AREA OF LOW PRESSURE
ACROSS THE WESTERN CARIBBEAN NEAR THE TAIL OF THE FRONTAL
BOUNDARY. RIDGING EXPECTED TO EXIST ACROSS NORTHERN MEXICO
NORMALLY LEADS TO DISTURBED WEATHER ACROSS THE TROPICAL EASTERN
PACIFIC SOUTH OF MEXICO...AND THE 12Z GLOBAL ENSEMBLE GUIDANCE
SHOWS TWO PROSPECTS FOR DEVELOPMENT DURING THE MEDIUM RANGE PERIOD.

The attachment 06122012 00Z GFS Ensembles 00zgfsensemble500mbHGHTtropical180.gif is no longer available

And the Canadian spins up a Tropical Storm...

[srainhoutx]

The 12Z Euro is developing a broad lower pressure disturbance in the Western Gulf next week.

[srainhoutx]

Afternoon snip from NWS Brownsville:

LONG TERM.../THURSDAY THROUGH TUESDAY/...MID LEVEL HIGH OVER
NORTHERN MEXICO WILL STILL BE THE DOMINANT WEATHER FACTOR FOR THE
REMAINDER OF THE WEEK. HOWEVER...BY THE END OF THE WEEK...ITS
INFLUENCE OVER DEEP SOUTH TEXAS WILL GRADUALLY BECOME LESS AS AN
UPPER LOW DEEPENS ACROSS BAJA MEXICO AND THE RIDGE AMPLIFIES AND
MOVES NORTHEAST INTO THE MIDWEST PORTION OF THE US. MEANWHILE DEEPER
TROPICAL MOISTURE WILL INCREASE AS A TROPICAL DISTURBANCE AND AREA
OF LOW PRESSURE MAKES ITS WAY INTO THE BAY OF CAMPECHE BY SATURDAY.
IF THIS SCENARIO PANS OUT...EASTERLY SURFACE FLOW AND DEEPER
TROPICAL MOISTURE WILL BRING ABOUT A CHANCE FOR SHOWERS OVER THE
WEEKEND. CONFIDENCE STILL NOT ALL THAT HIGH...BUT MODELS HAVE
PERSISTED WITH THIS SOLUTIONS FOR A COUPLE OF RUNS NOW. ANOTHER
TROPICAL SYSTEM MAY MAKE ITS WAY INTO THE GULF BY LATE NEXT WEEK.
BOTTOM LINE IS THE GULF BEARS WATCHING OVER THE NEXT WEEK OR TWO.

[Ptarmigan]

HPC Morning update from Forecaster Roth:

THIS PATTERN FAVORS A LATE SEASON COLD FRONTAL PASSAGE THROUGH THE
FLORIDA PENINSULA AND FLORIDA STRAITS AS THE REX BLOCK
RETROGRADES. BETWEEN SUNDAY AND TUESDAY...A MID-LEVEL CYCLONE IS
EXPECTED TO PASS BETWEEN BERMUDA AND THE EAST COAST...FAVORING THE
DEVELOPMENT OF DISTURBED WEATHER/A BROAD AREA OF LOW PRESSURE
ACROSS THE WESTERN CARIBBEAN NEAR THE TAIL OF THE FRONTAL
BOUNDARY. RIDGING EXPECTED TO EXIST ACROSS NORTHERN MEXICO
NORMALLY LEADS TO DISTURBED WEATHER ACROSS THE TROPICAL EASTERN
PACIFIC SOUTH OF MEXICO...AND THE 12Z GLOBAL ENSEMBLE GUIDANCE
SHOWS TWO PROSPECTS FOR DEVELOPMENT DURING THE MEDIUM RANGE PERIOD.



http://tropic.ssec.wisc.edu/real-time/m ... t72hrs.gif

06122012 00Z Euro Ensembles 00zecmwfenstropical500mbSLP168.gif

06122012 00Z GFS Ensembles 00zgfsensemble500mbHGHTtropical180.gif

And the Canadian spins up a Tropical Storm...

06122012 00Z Canadian f240.gif

This could be interesting. Looks to be a rain event. Now the question, how strong will it be. I think something will develop in the Gulf of Mexico.

[djmike]

Here we go...Media begins discussions about next weeks potential disturbance!

http://www.accuweather.com/en/weather-n ... once/66458

[srainhoutx]

The 12Z GFS is much more in line with what the overnight Euro suggested. We will see...

[djmike]

Watch this end up being a northern Mexico/Brownsville storm....AGAIN!

[Ptarmigan]

Watch this end up being a northern Mexico/Brownsville storm....AGAIN!

Dolly rained on my lawn. If its big enough, a Deep South Texas landfall can make everyone happy.

There was Tropical Storm Arlene in 1993. Made landfall in Deep South Texas and gave Texas a lot of rain.

[srainhoutx]

For what it's worth, the 00Z Canadian ensembles are not very 'bullish' on the Bay of Campeche potential...

[Andrew]

GFS continues to show a developing system in the bay of Campeche that crossed over from the East Pacific. 850mb Vort's show multiple vorticities that eventually combine into one vort max. Either way it shows a good amount of precipitation affecting the whole Texas coast. Whatever organizes will then dictate where the heaviest of the rain will be. Strength of the ridge will be key and models are indicating this could be a slow moving storm which could increase the flooding threat. I am not staying up for CMC and Euro but will check them out in the morning.

[srainhoutx]

The Euro/Canadian and UKMet are suggesting a broad surface low will develop in the medium to longer range as well. The Euro suggests the upper ridge will build back E over the area of disturbed weather while the Canadian is hinting a more closed surface low heading toward the Louisiana Coast. The UKMet develops a broad low in the Bay of Campeche. The GFS looks to bring that low further N into the Corpus Area. With that increase in guidance output suggesting some form of tropical mischief developing, we'll need to closely monitor future guidance as we are now beginning to get into the range that gives a bit more confidence that something may in fact develop.

[Katdaddy]

From this mornings Corpus Christi AFD:

ALL GUIDANCE IS INDICATING A SURGE OF DEEP
TROPICAL MOISTURE TOWARDS S TX LATE NEXT WEEK AS BROAD LOW PRESSURE
DEVELOPS IN THE BAY OF CAMPECHE. 00Z GUIDANCE SUITES ARE ALL
BRINGING THE SYSTEM/DISTURBANCE A LITTLE FARTHER NORTH AND A LITTLE
MORE ORGANIZED THAN PREVIOUS RUNS WHICH MAY LEAD TO INCREASING RAIN
CHANCES FOR ESPECIALLY THE SOUTHERN AND EASTERN CWA /AND ADJACENT
MARINE AREAS/. FOR NOW WILL GO WITH CHANCE POPS FOR WED AND THURS.
SYSTEM NEXT WEEK BEARS WATCHING.

[srainhoutx]

Some of the chatter from Texas/LA NWS offices this morning regarding next week:

Dallas/Ft Worth:

THE TROPICAL DISTURBANCE THAT WILL MOVE ACROSS THE
GULF EARLY NEXT WEEK STILL HAS THE POTENTIAL TO PRODUCE PRECIP
ACROSS THE SOUTHERN CWA ON TUESDAY AND WEDNESDAY. THIS SCENARIO
IS SUPPORTED BY BOTH THE GFS AND ECMWF. BY THURSDAY...MODELS START
TO DIVERGE. THE GFS NOW TAKES THE TROPICAL DISTURBANCE ON A MUCH
MORE NORTHERN TRACK AND RECURVES IT ACROSS NORTH TEXAS FRIDAY AND
SATURDAY. THE ECMWF HOLDS THE SUBTROPICAL RIDGE TO THE NORTH OF
THE TROPICAL SYSTEM AND SHUNTS IT WESTWARD INTO MEXICO. IF THE GFS
IS RIGHT...THE LATE WEEK TIME PERIODS WILL BE WET BUT SINCE THIS
IS A NEW WRINKLE I WILL STICK WITH CONTINUITY AND ADD NO POPS TO
THE FORECAST. IF THE ECMWF STARTS TO AGREE WITH THAT TRACK...THE
LATER FORECASTS WILL LIKELY BE ADDING POPS LATE NEXT WEEK.

Lake Charles:

THROUGH THE WEEKEND HIGH
PRESSURE AT THE SURFACE WILL GRADUALLY BUILD IN FROM THE NORTHEAST
WHICH WILL KEEP THE AREA IN A MOIST SOUTH TO SE FLOW. A MID LVL
RIDGE WILL GRADUALLY BUILD INTO TX AND THEN ACROSS THE REST OF THE
SOUTH THROUGH THE EARLY PARTS OF THE COMING WEEK. THIS WILL SLOWLY
SHOVE THE WEAK SHORT WAVE CURRENTLY OVER LA SOUTH INTO THE EXTREME
NW GULF OR PERHAPS JUST TO THE COAST OF LA BEFORE IT DEEPENS AND
RETRO GRADES INTO S TX. WITH THE SHORT WAVE/UPPER LOW IN VICINITY
OF THE CWA AND WITH CONTINUED MOISTURE BEING PUSHED ACROSS THE
AREA AROUND THE SUBTROPICAL RIDGE, ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED THROUGH THE WEEKEND AND THE
EARLY PART OF NEXT WEEK. BY THE MIDDLE OF THE COMING WEEK WINDS
WILL GRADUALLY INCREASE AS THE PRESSURE GRADIENT SLOWLY TIGHTENS
BETWEEN THE RIDGE TO THE NORTH AND LOWERING PRESSURE WELL TO THE
SOUTH. THIS WILL BE MOST NOTED ALONG THE COAST AND OVER THE
COASTAL WATERS.


Corpus Christi:

A MID/UPPER LEVEL
DISTURBANCE IS PROG TO RETROGRADE ACROSS W GULF TOWARDS CWA OVER THE
WEEKEND AND INTO EARLY NEXT WEEK. THIS WILL ALLOW FOR HEIGHTS TO
LOWER AND RESULTANT INCREASE IN INSTABILITY TO OCCUR...AND WITH
LIGHTER LOW LEVEL FLOW...ISOLATED SHOWERS AND THUNDERSTORMS SHOULD
DEVELOP ALONG THE SEABREEZE ON SUNDAY. GUIDANCE DIFFERS ON TRACK OF
MID LEVEL DISTURBANCE WITH GFS TAKING VORT MAX INTO HOUSTON WHILE
ECMWF AND CANADIAN MOVE THE SYSTEM INTO S TX. THE ECMWF/CMC SOLUTION
WOULD USUALLY BRING US SIGNIFICANT PRECIP BUT DEEP LAYER MOISTURE
WILL STILL BE LACKING TO AN EXTENT AND THUS HAVE ONLY GONE WITH
SLIGHT CHANCE TO CHANCE POPS FOR SUN AND MONDAY. CHANCES OF PRECIP
MAY INCREASE ON TUESDAY AS SAID DISTURBANCE PLACES S TX IN SLIGHTLY
MORE FAVORABLE DPVA REGION ALONG WITH INCREASING DEEP LAYER
MOISTURE. FORECAST CONFIDENCE THEN DECREASES FOR THE MIDDLE AND
LATTER HALF OF NEXT WEEK. ALL GUIDANCE IS INDICATING A SURGE OF DEEP
TROPICAL MOISTURE TOWARDS S TX LATE NEXT WEEK AS BROAD LOW PRESSURE
DEVELOPS IN THE BAY OF CAMPECHE. 00Z GUIDANCE SUITES ARE ALL
BRINGING THE SYSTEM/DISTURBANCE A LITTLE FARTHER NORTH AND A LITTLE
MORE ORGANIZED THAN PREVIOUS RUNS WHICH MAY LEAD TO INCREASING RAIN
CHANCES FOR ESPECIALLY THE SOUTHERN AND EASTERN CWA /AND ADJACENT
MARINE AREAS/. FOR NOW WILL GO WITH CHANCE POPS FOR WED AND THURS.
SYSTEM NEXT WEEK BEARS WATCHING. TEMPS TO BE AT OR SLIGHTLY ABOVE
NORMAL FOR MUCH OF EXTENDED PERIOD WITH A MODERATE TO AT OR JUST
BELOW NORMAL FOR MAX TEMPS BY LATE IN THE FORECAST DUE TO INCREASED
PRECIP AND CLOUD COVER.


Brownsville:

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...MODELS BECOMING
NICELY CONSISTENT ON OVERALL PATTERN FOR NEXT WEEK. HIGH PRESSURE
CONTINUES TO GET SQUEEZED WESTWARD AS THE TROUGH TRAPPED ACROSS
LOUISIANA CUTS OFF AND RETROGRADES BACK INTO THE NORTHWEST GULF
OVER THE WEEKEND. INSTABILITY WILL BE MODEST IN THIS AREA FROM
THAT FEATURE...AND WITH LIGHTER WINDS...THE SEABREEZE WILL HAVE A
BETTER SHOT AND PRODUCING CONVECTION AND SHOWERS FOR MOST OF NEXT
WEEK. THE NEXT FEATURE OF NOTE IS THE AREA OF SFC LOW PRESSURE
THAT ALL MODELS ARE TRYING TO WRAP UP IN THE BAY OF CAMPECHE LATE
WEEK AND DRIFT NORTHWARD ALONG THE FAR WESTERN GULF COAST.
WHILE THE MODELS MAKE THIS FEATURE LOOK EXCITING...IT IT WAY TOO
EARLY TO IMPLY ANYTHING TROPICAL OUT OF THIS FEATURE OR TO NAIL
DOWN THE TIMING OR LOCATION OF THIS FEATURE 8 DAYS OUT.



Houston/Galveston:

LONGER RANGE BEGINNING TO LOOK WET. WEAKNESS/EASTERLY WAVE ON THE
SOUTH SIDE OF THE MEAN SFC-700MB HIGH OVER THE SOUTHEASTERN US
EARLY NEXT WEEK WILL MOVE TOWARDS SE TEXAS. WEAK UPPER TROF AT
500-250MB REMAINS CLOSE BY AS WELL. AHEAD OF THE SFC FEATURE PWATS
CLIMB AND SE TX IN FAVORABLE LOCATION FOR LIFT SO 30/40 PERCENT
POPS SEEM PRUDENT. BOTH GFS AND EXPERIMENTAL ECMWF MOS RAISE POPS
FURTHER FOR MIDWEEK IN RESPONSE TO INCREASED ONSHORE FLOW FROM
POSSIBLE TROPICAL DEVELOPMENT IN BAY OF CAMPECHE. STILL WAY TOO
EARLY TO GET TOO EXCITED ABOUT THIS POSSIBLE DEVELOPMENT BUT STILL
TOO FAR OUT (LATE NEXT WEEK!) TO FINE TUNE TIMING OR LOCATIONS SO
BROAD BRUSH APPROACH SEEMS BEST FOR NOW. GFS RAISES PWAT VALUES
TREMENDOUSLY WHILE ECMWF IS MORE RESTRAINED. WENT GENERALLY WITH A
2 PARTS ECM AND 1 PART GFS BLEND IN THE EXTENDED.

[srainhoutx]

HPC:

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
938 AM EDT FRI JUN 15 2012

VALID 12Z TUE JUN 19 2012 - 12Z FRI JUN 22 2012

THE PRIMARY CLUSTER OF MEDIUM RANGE GUIDANCE CONTINUES TO INDICATE
THAT A BROAD MEAN TROF CENTERED OVER THE NWRN QUADRANT OF THE
LOWER 48 SHOULD SHARPEN A LITTLE DURING THE FIRST HALF OF THE
PERIOD AND THEN MOVE EWD... REACHING THE UPR MS VLY/WRN GRTLKS BY
DAY 7 FRI. UPSTREAM DURING THU-FRI MOST SOLNS EXPECT DEVELOPMENT
OF A MODERATELY AMPLIFIED ERN PAC TROF/WRN CONUS RIDGE. THE ERN
PAC MEAN TROF IS FCST TO CONSIST OF A NERN PAC TROF/EMBEDDED
CLOSED LOW ALONG WITH A LOWER LATITUDE CLOSED LOW BEING CAPTURED
BY THE NRN FEATURE. MEANWHILE RECENT ENSEMBLE GUIDANCE HAS BEEN
SHOWING AN INCREASINGLY FAVORABLE ENVIRONMENT FOR PSBL TROPICAL
DEVELOPMENT FROM THE NWRN CARIBBEAN INTO THE WRN GULF OF MEXICO BY
THE LATTER HALF OF THE PERIOD. THERE IS GENERALLY SUFFICIENT
AGREEMENT WITH THE LARGE SCALE FLOW TO RECOMMEND A CONSENSUS
APPROACH TO THE FCST.

WITHIN THE NRN STREAM MEAN TROF THERE IS REASONABLE AGREEMENT WITH
THE LEADING SYSTEM FCST TO TRACK NEWD FROM THE NRN PLAINS EARLY IN
THE PERIOD... WHILE DEVELOPING DETAIL DIFFS WITH UPSTREAM FLOW ARE
NOT YET SUFFICIENT TO HAVE SIGNIFICANT IMPACT ON THE SFC PATTERN.
THUS DAYS 3-4 MON-TUE START WITH A NEARLY EVEN BLEND OF THE 00Z
GFS/ECMWF/UKMET. BY DAY 5 WED THE UKMET BECOMES MORE SUPPRESSED
THAN MOST OTHER SOLNS WITH THE NEXT AREA OF LOW PRESSURE OVER THE
PLAINS... WITH A BLEND OF GFS/ECMWF RUNS AND GEFS/12Z ECMWF
ENSEMBLE MEANS PREFERRED. DAYS 6-7 THU-FRI USE THE ENSEMBLE MEANS
EXCLUSIVELY AS SOME ASPECTS OF INDIVIDUAL MODELS STRAY FROM THE
ENSEMBLE MEANS IN VARYING WAYS. THE 00Z ECMWF BECOMES
FLATTER/FASTER THAN CONSENSUS OR CONTINUITY WITH NRN STREAM ERN
PAC FLOW THUS LEAVING BEHIND THE LOWER LATITUDE CLOSED LOW... AND
LEADING TO MORE PROGRESSIVE FLOW DOWNSTREAM AS WELL. THE CANADIAN
AND EVENTUALLY TO A LESSER EXTENT GFS ARE FASTER THAN THE GUIDANCE
AVERAGE TO LIFT THE LOWER LATITUDE ERN PAC CLOSED LOW ENERGY
TOWARD THE WEST. FARTHER EWD THE GFS BECOMES MORE SEPARATED THAN
MOST OTHER SOLNS WITH ITS SHRTWV CROSSING THE NRN PLAINS/UPR MS
VLY BY THU-FRI. OVER THE GULF... THE CANADIAN DISPLAYS A
SEEMINGLY LOW PROBABILITY SFC LOW REACHING THE GULF COAST BY DAY 7
FRI WHILE THE GFS TRENDS SLIGHTLY TO THE NRN SIDE OF THE SPREAD
WITH ITS WRN GULF LOW. WITH THIS FEATURE THE EARLY PRELIM FCST
HOLDS ONTO YDAYS CONTINUITY THRU DAY 6 WITH DAY 7 EXTRAPOLATION
STAYING TO THE S OF THE GFS.

[srainhoutx]

The 12Z GFS continues to advertise a broad low pressure circulation developing with the monsoonal trough gyre that brings some mid level vorticity for the remnants of Carlotta as well as some mid level rotation for the NW Caribbean. This type of monsoonal gyre usually is slow to develop and will have multiple areas of vorticity or spin around the larger low pressure system much like what is seen with WPAC tropical cyclones. Whether or not anything develops, moisture and long fetch E to SE flow from the Gulf will become well established and rain chances should increase accordingly.