[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231736
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 23 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A WELL DEFINED TROPICAL WAVE IS ALONG 27W/28W S OF 13N MOVING W
10-15 KT. A 1010 MB LOW WAS ADDED ALONG THE WAVE AXIS NEAR 6N...
BASED ON PRONOUNCED LOW-LEVEL TURNING APPARENT ON VISIBLE IMAGES
AND A FAIR AMOUNT OF CURVATURE IN AN EARLIER QSCAT PASS...
DESPITE MUCH RAIN FLAGGING. CONVECTION IS CONFINED TO AN AREA N
OF THE LOW CENTER FROM 7N-9N BETWEEN 26W-29W.

A WEAK TROPICAL WAVE IS ALONG 59W S OF 12N MOVING W 10 KT. THIS
WAVE CONTINUES TO BE FAIRLY STRAIGHTFORWARD TO TRACK AS A WEAK
INVERTED V-PATTERN IS EVIDENT IN THE LOW-LEVEL CLOUD FIELD. TSTM
ACTIVITY IS MAINLY INLAND OVER SOUTH AMERICA...BUT SCATTERED
SHOWERS ARE POSSIBLE WITHIN 150 NM OF THE WAVE AXIS.

A TROPICAL WAVE IS OVER E PORTIONS OF CENTRAL AMERICA ALONG 84W
S OF 17N MOVING W 10 KT. THE WAVE IS MOVING SLOWLY W AND HAS
BECOME DIFFICULT TO TRACK AS IT IS EMBEDDED IN STRONG LOW-LEVEL
SW WINDS. LOW-LEVEL CONVERGENCE COMBINED WITH UPPER DIFFLUENCE
IS PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM E OF THE
AXIS N OF 12N.

..THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N11W 5N18W 6N23W 4N33W 3N51W.
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 300 NM EITHER
SIDE OF THE AXIS W OF 44W...FROM 7N-10N BETWEEN 19W-21W...WITHIN
60 NM N OF THE AXIS E OF 16W AND FROM 1N-4N E OF 18W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS A LARGE AREA OF DRY AIR ALOFT
SPREADING NE BY STRONG SW FLOW...MOST PRONOUNCED W OF ABOUT 88W.
HOWEVER...A WEAK SHORTWAVE OVER MISSISSIPPI AND ALABAMA HAVE
BEEN PRODUCING SCATTERED SHOWERS AND TSTMS OVER THE NE WATERS N
OF 28N E OF 87W THROUGHOUT THE MORNING HOURS. IR IMAGES INDICATE
WARMING OF THE CLOUD TOPS OVER THE PAST FEW HOURS...BUT
LIGHTNING AND RADAR DATA STILL SUGGEST SOME EMBEDDED TSTM
ACTIVITY. ISOLATED SHOWERS ARE ELSEWHERE N OF 25N E OF 88W. THE
REMAINDER OF THE GULF IS DOMINATED BY FAIR WEATHER...THOUGH
VISIBLE IMAGES SHOW AN AREA OF HAZE IN THE E BAY OF CAMPECHE AND
A SLIGHTLY LESS DENSE AREA OVER THE REMAINDER OF THE W GULF FROM
FIRES ON THE YUCATAN PENINSULA AND OTHER PORTIONS OF MEXICO. A
BACK DOOR TYPE COLD FRONT IS EXPECTED TO SWEEP THROUGH FLORIDA
AND THE E GULF SUN AND MON...COOLING TEMPS ONLY SLIGHTLY BUT
ALLOWING NOTICEABLY DRIER AIR TO FILTER INTO THE REGION.

CARIBBEAN SEA...
CONVECTIVE ACTIVITY IS CONFINED TO THE FAR W/SW PORTION OF THE
BASIN NEAR AND OVER THE NICARAGUA AND HONDURAS COASTS FROM
12N-17N BETWEEN 82W-85W. THESE SCATTERED SHOWERS AND TSTMS ARE
ASSOCIATED WITH UPPER DIFFLUENT FLOW AND AIDED BY A SLOW MOVING
TROPICAL WAVE ALONG 84W. THE REMAINDER OF THE BASIN IS
EXPERIENCING MAINLY FAIR WEATHER THANKS IN PART TO A STABLE MID
TO UPPER ENVIRONMENT...SUPPORTED BY AN UPPER HIGH JUST S OF
CENTRAL CUBA AND AN UPPER LOW OVER N VENEZUELA. THE DRIEST AIR
IS IN THE CONFLUENT ZONE BETWEEN 67W-79W. A QSCAT PASS SHORTLY
AFTER 11Z REVEALED THE STRONGEST WINDS OVER THE NW WATERS...SE
20-25 KT. THE BUOY 42056 IN THE REGION HAS INCREASED TO NEAR 30
KT OVER THE PAST COUPLE OF HOURS AND IS REPORTING 10 FT SEAS.
THIS FLOW IS EXPECTED TO REMAIN STRONG THROUGH TOMORROW. A WEAK
TROPICAL WAVE MAY INCREASE LOW-LEVEL MOISTURE ACROSS THE FAR SRN
WINDWARDS AND EXTREME SE WATERS TOMORROW.

ATLANTIC OCEAN...
STRONG UPPER W TO NW FLOW LIES OVER THE W ATLC BETWEEN AN UPPER
HIGH OVER THE CARIBBEAN AND A DEEP LAYER LOW NEAR NEWFOUNDLAND.
THIS PATTERN IS PRODUCING AND TRANSPORTING A SWATH OF CLOUDINESS
N OF 25N W OF ABOUT 50W. HOWEVER...SCATTERED SHOWERS AND TSTMS
ARE CONFINED TO A SMALLER REGION IN AN UPPER DIFFLUENT ZONE
WITHIN 180 NM SE OF A COLD FRONT FROM 31N63W TO 30N68W. THE
REMAINDER OF THE ATLC W OF 50W IS EXPERIENCING MAINLY FAIR
WEATHER. E OF 50W...A LARGE UPPER LOW IS THE DOMINATE FEATURE
ALOFT SPINNING NEAR 28N42W WITH INDUCING TROUGHING STRETCHING S
TO THE EQUATOR NEAR 40W. THERE COULD BE A FEW SHOWERS WITHIN 300
NM OF THE UPPER LOW AND ALONG THE AXIS FROM 17N-20N BETWEEN
41W-44W. OTHERWISE...ONLY HIGH LEVEL CLOUDS ARE SCATTERED ACROSS
THE E ATLC TRANSPORTED BY STRONG SW UPPER FLOW BETWEEN THE UPPER
LOW/TROUGH AND AN UPPER RIDGE OVER W AFRICA.

AT THE SFC...BESIDES FOR THE AFOREMENTIONED COLD FRONT THAT
CLIPS THE DISCUSSION ZONE AND A COUPLE OF LOW-LATITUDE TROPICAL
WAVES...HIGH PRES RIDGING IS THE THEME ANCHORED BY A 1026 MB
HIGH ABOUT 420 NM SW OF THE AZORES NEAR 35N37W.

$$
CANGIALOSI




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