AFD San Juan about Atlantic future Developments

[cycloneye]

000
FXCA62 TJSJ 231005
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
605 AM AST SAT SEP 23 2006

.DISCUSSION...
SOMEWHAT COMPLEX UPPER LEVEL PATTERN FROM THE E CARIB INTO THE
CENTRAL ATLC THIS MORNING AS TUTT AXIS FROM S AMERICA NE INTO THE
CENTRAL ATLANTIC SHIFTS WWD...AND DOUBLE VORTS NORTH OF THE NE
CARIB SHIFT SW NEXT 24 HOURS AND GRADUALLY MERGE INTO NEWLY
ALIGNED TUTT AXIS. ALTHOUGH THE VORTS SINKING SW INTO THE LOCAL
AREA ATTM ARE PRESENTLY BRINGING DRIER AIR ALOFT...BEST UPPER
CONVERGENCE AND SINKING MOTIONS SHOULD SHIFT FAR W OF THE LOCAL
AREA WITH UNSTABLE CONDITIONS ALOFT EXPECTED TO PREVAIL THIS
AFTERNOON ACROSS PR AND HISPANIOLA. MILD ENE LLVL FLOW WILL ADVECT
AMPLE LLVL MOISTURE INTO THE AREA TODAY AND RESPOND TO DIURNAL
PROCESSES TO INDUCE ANOTHER DAY OF REASONABLY ACTIVE AFTERNOON-
EARLY EVENING WEATHER. INCREASE IN LLVL FLOW TO 10-15 KNOTS FROM
PREVIOUS DAY SWILL AID IN STRONGER LLVL FORCING. WEAK LLVL TROFFING
TRAILING FROM THE SW PERIPHERY OF HELENE INTO THE OFFSHORE ATLC
WILL LIFT OUT TONIGHT AND ALLOW FOR W ATLC HIGH TO BUILD WEAKLY
INTO THE REGION...WITH LLVL WINDS SLOWLY VEERING OVER THE NEXT FEW
DAYS AS HIGH SHIFTS SE INTO THE CENTRAL ATLC.

TROPICAL WAVE LIMPING SLOWLY W ALONG NEAR 57 WEST THIS MORNING
WILL MOVE WNW INTO THE CARIB SUNDAY AND THEN NW ACROSS THE LOCAL
AREA MONDAY-TUESDAY...AND BRING INCREASING DEEP LAYERED MOISTURE.
TUTT AXIS WILL HAVE SHIFTED W AND NW BY THEN...AND WE WILL REMAIN
ON THE S SIDE FOR MODERATELY UNSTABLE UPPER CONDITIONS THROUGH THE
MIDDLE OF THE WEEK. AS THE TROPICAL WAVE FOLLOWS MEAN DEEP LAYERED
STEERING FLOW AND MOVES NW INTO THE BAHAMAS BY MID WEEK...A DEEP
LAYERED FLOW OF TROPICAL MOISTURE WILL TRAIL THE WAVE AND REMAIN
ACROSS THE LOCAL AREA FOR HIGH RAIN CHANCES. NEXT TROPICAL WAVE
"COMPLEX" CURRENTLY ACROSS CENTRAL ATLC IS FORECAST BY GLOBAL
MODELS TO BE PULLED NNW AND THEN WNW AND LIFT LARGELY OUT OF THE
LOCAL REGION. HOWEVER... THIS WAVE HAS/HAD A DOUBLE VORT
STRUCTURE...AND I AM STILL NOT SOLD ON ENTIRE WAVE LIFTING
COMPLETELY OUT OF TROPICS. WILL HAVE TO WAIT AND SEE HOW THIS
EVOLVES TO SEE HOW LITTLE MOISTURE AND ENERGY FROM THIS WAVE MAKES
IT INTO THE LOCAL AREA THURSDAY-FRIDAY.


GFS HAS CONTINUED SPIN UP WAVE JUST OFF W AFRICA TO VARIOUS
DEGREES OF INTENSITY PAST MANY RUNS...BUT CONTINUES TO BRING THAT
WAVE OR A TROPICAL LOW INTO THE NE CARIB NEXT WEEKEND. THIS BEARS
WATCHING.

BOTTOM LINE TO THIS RANTING IS THAT WE HAVE BEGUN TO TRANSITION
FROM A DRY PATTERN FROM THE PAST WEEK...INTO A WET PATTERN WITH
SOME POTENTIAL FOR BRIEF PERIODS OF HEAVY TROPICAL RAINS
THROUGHOUT THE NEXT SEVERAL DAYS. ADDITIONALLY...THE TROPICAL
ATLANTIC IS NOT YET DONE MANUFACTURING TROPICAL SYSTEMS THIS
YEAR...AND WE THUS NEED TO KEEP A VIGILANT MINDSET.


http://www.srh.noaa.gov/fwd/productview ... &version=0

Very interesting comments from the forecaster here at the San Juan office about what he sees in the next few days in terms of tropical activity for the Eastern Caribbean.

[rainstorm]

we must remain vigilant

[cycloneye]

we must remain vigilant

Definitly,it's not over yet.

[msbee]

Luis
I always enjoy the tropical discussions from PR. They are very thorough and informative.
But I can't say I particularly like what he says when he says
..." I AM STILL NOT SOLD ON ENTIRE WAVE LIFTING
COMPLETELY OUT OF TROPICS. WILL HAVE TO WAIT AND SEE..."
This time of year we know though that it is always a wait and see kind of thing..
The forecaster has a good sense of humor, calling his discussion "ranting"
that's pretty funny!

Barbara

[Fego]

For those who sometimes talks about the end of the season, or the Cabo Verde season, this is a perfect reminder that is not over until is over.

GFS HAS CONTINUED SPIN UP WAVE JUST OFF W AFRICA TO VARIOUS
DEGREES OF INTENSITY PAST MANY RUNS...BUT CONTINUES TO BRING THAT
WAVE OR A TROPICAL LOW INTO THE NE CARIB NEXT WEEKEND. THIS BEARS
WATCHING.....
......THE TROPICAL
ATLANTIC IS NOT YET DONE MANUFACTURING TROPICAL SYSTEMS THIS
YEAR...AND WE THUS NEED TO KEEP A VIGILANT MINDSET.

[cycloneye]

Luis
I always enjoy the tropical discussions from PR. They are very thorough and informative.
But I can't say I particularly like what he says when he says
..." I AM STILL NOT SOLD ON ENTIRE WAVE LIFTING
COMPLETELY OUT OF TROPICS. WILL HAVE TO WAIT AND SEE..."
This time of year we know though that it is always a wait and see kind of thing..
The forecaster has a good sense of humor, calling his discussion "ranting"
that's pretty funny!

Barbara

Especially forecaster Snell,do very long discussions and goes to every factor from the upper levels to the lower levels in detail as he did this afternoon.

FXCA62 TJSJ 232017
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
417 PM AST SAT SEP 23 2006

.SYNOPSIS...AT UPPER LEVELS...A WEAK TROUGH EXTENDS NORTHEAST FROM
THE CENTRAL CARIBBEAN. BY SUNDAY NIGHT IT WILL HAVE MOVED TO
JAMAICA AND HIGH PRESSURE WILL BEGIN TO DOMINATE THE LOCAL AREA.
THIS HIGH PRESSURE IS EXPECTED TO CONTINUE THROUGH THE REST OF THE
UPCOMING WEEK.

AT MID LEVELS...A GENERAL AREA OF HIGH PRESSURE COVERS THE WESTERN
ATLANTIC AND EXTENDS SOUTH INTO THE CARIBBEAN. THIS HIGH WILL BE
DISPLACED TO THE EAST BY A LONG WAVE TROUGH MOVING INTO THE
SOUTHEASTERN UNITED STATES DURING THE END OF THE WEEK...BUT WILL
CONTINUE TO AFFECT THE CARIBBEAN.


AT LOWER LEVELS...A TROPICAL WAVE WITH SOME CONVECTION IS NEAR 57
WEST AND IS MOVING WEST AT AROUND 10 KNOTS. IT IS EXPECTED TO
CROSS THROUGH THE AREA EARLY MONDAY MORNING WITH MOISTURE
CONTINUING BEHIND THE WAVE FOR SEVERAL DAYS. A SECOND AND MUCH
BROADER WAVE WITH SOME CYCLONIC CIRCULATION IS AT 42 WEST AND
FOLLOWED BY A LOW PRESSURE NEAR 39 WEST. OTHER WAVES...WHICH ARE
MUCH LESS ORGANIZED WILL FOLLOW...AND MAY BECOME MORE ORGANIZED LATER.

&&

.DISCUSSION...VERY GOOD MOISTURE AND A LIFTED INDEX LESS THAN
MINUS 8 PRECEDED TODAYS ACTIVE CONVECTION THAT HAS SO FAR BEEN
ABLE TO PUSH SEVERAL RIVERS INTO FLOOD FOR THE AFTERNOON.
CONVECTION WAS ALSO AIDED BY AN UPPER LEVEL TROUGH THAT IS SLOWLY
DRIFTING WEST AND HAD ENHANCED UPWARD MOTION IN THE ATMOSPHERE.
CURRENT GFS IS SHOWING DRYER AIR AT 850 MB ON SUNDAY BUT MOISTURE
DOES NOT REACH MAXIMUM LEVELS UNTIL TUESDAY AT 12Z. THEREFORE BEST
RAINFALL CHANCES HAVE BEEN DELAYED UNTIL MONDAY AFTERNOON AND
NIGHT. MOISTURE CONTINUES THROUGH TUESDAY IN SOUTHEAST FLOW. THE
GFS ALSO SUGGESTS THAT ANOTHER WAVE WILL PASS THROUGH ON THURSDAY
ACCOMPANIED BY MORE SHOWERS.

THE GENERAL FLOW IS EXPECTED TO BECOME MORE SOUTHEASTERLY SUNDAY
AND TEMPERATURES ON THE NORTH COAST SHOULD BE A LITTLE WARMER
BEFORE SHOWERS BEGIN. ON MONDAY THERE MAY BE SUFFICIENT MOISTURE
FOR SCATTERED SHOWERS IN THE MORNING...ESPECIALLY IN THE U.S. AND
THEN MORE WIDESPREAD SHOWERS OVER THE REST OF THE ISLANDS.

CONFIDENCE IN WIND DIRECTION AND SHOWER CHANCES DECREASES
CONSIDERABLY TOWARD NEXT WEEKEND WHEN THE MODEL BRINGS A LOW
PRESSURE TOWARD THE AREA AND OVER THE LEEWARD ISLANDS BY 00Z 1
OCTOBER.

MARINE...HURRICANE HELENE AND OTHER AREAS OF INCREASED
WINDS...PARTICULARLY THAT OVER THE NEXT WAVE WILL INCREASE LOCAL
SEAS BY TUESDAY...CURRENT WAVE WATCH IS SHOWING JUST UNDER 6 FEET
AND SO WILL STAY WITH 6 TO 7 FOOT FORECAST INHERITED. SHOWERS AND
THUNDERSTORMS OVER LOCAL WATERS WILL INCREASE CONSIDERABLY
BEGINNING SUNDAY NIGHT AND CONTINUING THROUGH TUESDAY.


&&

.AVIATION...AN UNSTABLE ATMOSPHERE HAS PUSHED TOPS WELL INTO THE
40 THOUSAND FOOT RANGE. THIS WILL LIKELY RETURN SUNDAY...WITH A
FOCUS FARTHER NORTHWEST. OTHERWISE GOOD VISIBILITIES SHOULD BE HAD
OUTSIDE OF THUNDERSTORMS. ONE CAVEAT...MONTSERRAT IS STILL
PRODUCING LIGHT ASH THAT IS VISIBLE CURRENTLY AS A PLUME EXTENDING
WEST FROM THE ISLAND TO SOUTHEAST OF SAINT CROIX AND IT WILL HAVE
TO BE WATCHED LATER IN THE WEEK WHEN WINDS WITH A STRONGER
SOUTHERLY COMPONENT ARE FORECAST.


He seems not so confident yet on that GFS system.

[hurricanetrack]

Here we go. A late season menace could be in the making. All it takes is one- will this be the "one" for 2006? We shall most certainly find out. Good to see lots of people paying attention and not letting their guard down. We might need some reports from Luis here in the next week or so- but I am putting the cart WAY before the horse right now. First, let's see if cyclogenesis takes place where the GFS has said it will- for 6 or 7 runs in a row.

[cycloneye]

000
FXCA62 TJSJ 241035
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
635 AM AST SUN SEP 24 2006

.SYNOPSIS...
TUTT AXIS EXTENDING FROM NEAR JAMAICA ENE ACROSS HISPANIOLA AND
JUST NORTH OF PR AND CONTINUES INTO CENTRAL ATLC SE OF DEPARTING
HELENE...WITH ANOTHER TROPICAL UPPER TROF ROTATING NW THROUGH THE
E CARIB AND BEGINNING TO MERGE OR REINFORCE TUTT SEGMENT IN
CENTRAL CARIB. DEEP LAYERED HIGH ACROSS W ATLC. AN AEW IS LOCATED
ACROSS THE SE CARIB FROM THE COAST OF VENEZUELA AT 64W...NNE TO
THE CENTRAL LEEWARDS. THIS WAVE LEFT AFRICA ON THE 14-15TH AND WAS
STRONGLY STRETCHED AND SHEARED N TO S WHILE EXITING AWAY FROM THE
CONTINENT...WITH SOUTHERN PORTION MOVING SLOWLY W ACROSS ATLC WITH
SIGNAL LARGELY S OF 16N. MEAN LOW TO MID LEVEL SE FLOW WILL GUIDE
THIS WAVE NW NEXT FEW DAYS. A SECOND LARGE AEW IS ACROSS THE
CENTRAL ATLC...WITH ALL OBJECTIVE ANALYSIS CLEARLY SHOWING A
NEGATIVE SSW TO NNE TILT/ELONGATION OF THE LLVL CIRCULATION. THE
NORTHERN VORT HAS ATTEMPTED TO SPIN UP THE PAST SEVERAL DAYS...AND
NHC HAS BEEN RUNNING HURRICANE GUIDANCE ON A LLVL CENTER IN THE
NORTHERN PORTION OF THIS WAVE...BUT DEEP LAYERED SSW SHEAR SEEMS
TO BE INHIBITING SUSTAINED OR INCREASED CONVECTIVE GROWTH. SAL HAS
ALSO BEEN A NEGATING FACTOR IN W AND SW QUADS THROUGHOUT THE PAST
WEEK. WIND ENVELOPE OF THIS FEATURE MOVING WNW PAST 12-24 HOURS. A
THIRD AEW IS OFF THE AFRICAN COAST ALONG ABOUT 22-23W WITH STLT
IMAGERY AND EARLY MORNING QUIKSCAT PASS SUGGESTING A SURFACE LOW
INVOF 8N 22W.

&&

.DISCUSSION...
TROPICAL WAVE MOVING ACROSS LEEWARDS WILL MOVE WNW THIS MORNING
AND THEN MORE NW NEXT FEW DAYS...AND PASS LARGELY JUST SOUTH OF
THE LOCAL AREA. HOWEVER...THE NORTHERN FRINGES WILL MOVE ACROSS
THE LOCAL AREA...AND COMBINED WITH INCREASING LLVL FLOW AND
INSTABILITY FROM TUTT SHOULD PRODUCE ANOTHER ACTIVE WEATHER DAY.
MODELS STILL SUGGEST A GENERALLY MOIST AND UNSTABLE SELY LLVL FLOW
STREAMING ACROSS THE LOCAL AREA BEHIND THE EXITING WAVE MONDAY
THROUGH WEDNESDAY FOR CONTINUATION OF WET WEATHER PATTERN...
MODERATELY HIGH RAIN CHANCES...AND POSSIBILITY OF ISOLATED AREAS
OF VERY HEAVY RAINS. RECENT RAINFALL OF PAST FEW DAYS SUGGEST THAT
ISOLATED AREAS WILL AGAIN SEE 3-6 HOUR RAIN TOTALS OF 3-6
INCHES...MAINLY DUE TO DIURNAL FORCING. CENTRAL ATLC WAVE IS
EXPECTED TO PASS MAINLY NORTH OF THE AREA AS IT MOVE NW INTO THE W
CENTRAL ATLC LATE IN THE WEEK...BUT THE SOUTHERN PORTION OF THE
WAVE WILL LIKELY CEROSS THE AREA TO MAINTAIN OUR WET AND UNSTABLE
PATTERN...WHICH MAY CONTINUE INTO THE WEEKEND.

GLOBAL MODELS HAVE BEEN INSISTENT ON MOVING WAVE OFF AFRICA THIS
MORNING WNW AND INTO THE LOCAL AREA IN SOME FORM OR FASHION BY
NEXT SUN-MON...BUT LAST 2 RUNS OF GFS HAVE CHANGED CONSIDERABLY
WITH THIS WAVE NOW BEING GRABBED BY DEEP LAYERED CENTRAL ATLC TROF
AND IS NUDGED SLOWLY BACK TOWARD THE E. VERY INTERESTING SCENARIO.
WILL HAVE TO WATCH THIS WAVE AND THEN NEXT FEW AS CAPE VERDE
SEASON IS NOT YET OVER.


Let's see what happens this week in the Atlantic with this.

[caribepr]

And the CV / Caribbean tennis match continues into the next round...again

[knotimpaired]

And they were about to start laying the rebar for the pool monday.....

Oh well.