[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI JUN 15 2007

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 TROPICAL WAVE HAS BEEN ADJUSTED SLIGHTLY ALONG 31W S OF 13N
MOVING W NEAR 15 KT. THIS UPDATED PSN IS PLACED ALONG THE AXIS
OF AN INVERTED V-SHAPE SEEN ON SATELLITE IMAGERY. IN
ADDITION...A QSCAT PASS AROUND 8Z SHOWED SOME TURNING IN THE
FLOW ALONG THE SRN PORTION OF THE ANALYZED PSN AND AN
INCREASE IN THE WINDS BEHIND THE AXIS. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE WITHIN 180 NM EITHER SIDE OF THE WAVE AXIS.

A WEAK TROPICAL WAVE IS IN THE ERN CARIBBEAN ALONG 66W S OF 16N
MOVING W NEAR 15 KT. THIS WAVE IS NO LONGER DISCERNIBLE IN
SATELLITE PICTURES OR SFC OBSERVATIONS AND LIES IN A REGION OF
VERY STABLE AIR TO THE W OF A LARGE UPPER LOW E OF THE LESSER
ANTILLES.

A LOW AMPLITUDE TROPICAL WAVE IS MOVING ACROSS THE SRN CARIBBEAN
ALONG 75W/76W MOVING W 10-15 KT. SIMILARLY TO THE WAVE IN THE E
CARIB...THIS ONE IS NOT RECOGNIZABLE IN CURRENT DATA. THEREFORE
THE PSN IS BASED ON CONTINUITY. A CLUSTER OF MODERATE CONVECTION
IS MOVING W OVER PANAMA AND WRN COLOMBIA...LIKELY ASSOCIATED
WITH THE ITCZ.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 6N22W 7N29W 6N40W 5N53W.
BESIDES FOR CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE...ISOLATED MODERATE IS WITHIN 150 NM EITHER SIDE OF THE
AXIS BETWEEN 15W-22W AND 34W-41W. SIMILAR ACTIVITY IS WITHIN 60
NM N OF THE AXIS W OF 41W.

...DISCUSSION...

THE GULF OF MEXICO...
WEAK SFC PRES PATTERN CONTINUES IN THE GULF ASSOCIATED WITH A
TROUGH OF LOW PRES EXTENDING NEWD FROM THE NW CARIB AND LARGER
SCALE TROUGHING STRETCHING W FROM THE WRN ATLC. THE NET EFFECT
IS LIGHT WINDS AND LOW SEAS. MOISTURE WISE...THE MOST
SIGNIFICANT AREA IS LOCATED TO THE SE OF THE REGION PRODUCED BY
THE CARIB TROUGH. DOPPLER RADAR SHOWS THE NRN FRINGE OF THIS
MOISTURE PLUME PUSHING TOWARD S FLA...WITH THE DEEPER STEADY
PRECIP FURTHER S. MORE ON THIS FEATURE IN THE CARIBBEAN SECTION.
SCATTERED SHOWERS AND TSTMS HAVE ALSO DEVELOPED OVER THE COASTAL
WATERS OF E TX AND WRN LA. THIS ACTIVITY IS LIKELY CAUSED BY
INSTABILITY ASSOCIATED WITH AN UPPER LOW OVER OKLAHOMA AIDED BY
LOW-LEVEL INFLOW. ELSEWHERE AN UPPER RIDGE ALONG 92W IS
PROVIDING A STABLE AIRMASS ALLOWING FAIR CONDITIONS TO PREVAIL.

THE CARIBBEAN SEA...
SCATTERED SHOWERS AND TSTMS ARE AFFECTING A LARGE PORTION OF THE
NW CARIB N OF 18N GENIALLY BETWEEN 76W-85W...WHICH INCLUDES
NEARLY ALL OF THE ISLAND OF CUBA. THIS ACTIVITY IS ASSOCIATED
WITH DEEP LAYER TROUGHING ACROSS THE REGION. THE SFC BOUNDARY IS
ANALYZED FROM HONDURAS TO THE SE GULF ALONG 14N87W 21N87W
25N83W. AN ILL-DEFINED 1009 MB LOW SITS ON THE TROUGH IN THE
GULF OF HONDURAS NEAR 17N88W. ALL OF THE DEEP CLOUDINESS/
CONVECTION IS LOCATED TO THE E OF THE SFC TROUGH...MORE IN LINE
WITH DIFFLUENCE ALOFT ALONG AND E OF THE UPPER LOW.
OVERALL...THIS SYSTEM HAS BECOME LESS ORGANIZED THAN IT WAS
YESTERDAY. NWP MODELS SHOW THIS MOISTURE PLUME SLOWLY PRESSING
TO THE NW AFFECTING THE YUCATAN AND PORTIONS OF THE SE GULF THIS
WEEKEND.

WIDESPREAD FAIR WEATHER...BESIDES FOR THE TYPICAL ISOLATED TRADE
WIND SHOWERS...DOMINATE THE CENTRAL AND ERN CARIB. THESE
TRANQUIL CONDITIONS ARE BEING PRODUCED BY UPPER CONFLUENCE
BETWEEN A RIDGE OVER CENTRAL AMERICA AND A LARGE UPPER LOW E OF
THE LESSER ANTILLES. TRADES WINDS ARE A QUITE STRONG 20-30 KT IN
THIS REGION DUE TO A TIGHT PRES GRADIENT BETWEEN LOW PRES OVER
COLOMBIA AND BROAD RIDGING NE OF THE AREA.

THE ATLANTIC OCEAN...
EXTENSIVE W TO SWLY UPPER FLOW TO THE S OF A LARGE HIGHLY
ELONGATED UPPER TROUGH COVERS THE ATLC WATERS W OF 60W. AN
ASSOCIATED SFC BOUNDARY EXTENDS FROM 30N68W ACROSS THE NRN
BAHAMAS. THIS BOUNDARY APPEARS TO BE BECOMING DIFFUSE AND MAY BE
DROPPED AT 18Z. IR IMAGERY AND LIGHTNING DATA SUGGEST SCATTERED
SHOWERS AND TSTMS ACROSS THE CENTRAL BAHAMAS POINTS S OVER CUBA
WITH A PLUME OF MID-HIGH LEVEL CLOUDS NE OF THERE WITHIN 300 NM
E OF A LINE ALONG 26N75W 32N63W.

THE REMAINDER OF THE ATLC...E OF 60W...LIES IN A REGION OF DRY
STABLE AIR. THE DRIEST AIR IS IN CONFLUENT ZONES BETWEEN AN
UPPER LOW E OF THE LESSER ANTILLES NEAR 15N57W...AN UPPER HIGH
NEAR 28N47W AND ANOTHER UPPER HIGH NEAR 17N28W. THE SFC PATTERN
IS JUST ABOUT AS TRANQUIL WITH A BROAD RIDGE EXTENDING NEARLY
E-W ALONG 27N. THESE PATTERNS ARE MAINTAINING WIDESPREAD FAIR
WEATHER AND MODERATE TRADES ACROSS THIS REGION.

$$
CANGIALOSI


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