Tropical Weather Discussion
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000
AXNT20 KNHC 121035
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 12 2014

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...
TROPICAL WAVE CAME OFF THE WEST AFRICAN COAST ENGULFED BY THE
SAHARAN AIR LAYER EARLIER THIS MORNING. THE SOUTHERN PORTION OF
THE WAVE IS EMBEDDED IN THE MONSOON TROUGH WHICH IS SUPPORTING A
CLUSTER OF MODERATE/STRONG CONVECTION AND TSTMS SE OF THE AXIS
FROM 8N-12N E OF 19W.

TROPICAL WAVE IS OVER THE CENTRAL ATLC JUST N OF THE ITCZ WITH
AXIS EXTENDING FROM 19N43W TO 9N44W MOVING W AT 20-25 KT. THE
WAVE IS COMPLETELY EMBEDDED IN THE DRY SAHARAN AIR LAYER WHICH
IS HINDERING DEVELOPMENT OF DEEP CONVECTION AT THE TIME.

TROPICAL WAVE IS LOCATED OVER THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 20N74W TO 10N76W MOVING W AT 20 KT. DEEP LAYER
MOISTURE IS ASSOCIATED WITH THE WAVE. HOWEVER...STRONG DEEP
LAYER ENVIRONMENTAL SHEAR IS INHIBITING THE DEVELOPMENT OF
CONVECTION OVER CARIBBEAN WATERS. SCATTERED MODERATE CONVECTION
AND TSTMS ARE OVER THE WINDWARD PASSAGE COINCIDING WITH AN AREA
OF UPPER-LEVEL DIFFLUENCE.

TROPICAL WAVE HAS MOVED ACROSS THE YUCATAN PENINSULA...NORTHERN
CENTRAL AMERICA AND THE E PAC WATERS. ITS AXIS EXTENDS FROM
20N87W TO 9N90W MOVING W AT 20-25 KT. TOTAL PRECIPITABLE WATER
IMAGERY SHOWS LIMITED MOISTURE ACROSS THIS REGION...THUS
RESULTING IN A LACK OF ANY SIGNIFICANT DEEP CONVECTION OVER
WATER AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 9N13W TO
7N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
7N18W TO 8N38W TO 6N57W. BESIDES THE CONVECTION ASSOCIATED WITH
THE WAVES...SCATTERED MODERATE CONVECTION IS FROM 4N-10N BETWEEN
19W-32W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRESSURE AND RIDGING CONTINUE TO DOMINATE THE GULF
WATERS. IN THE MID-UPPER LEVELS...AN ANTICYCLONIC CIRCULATION
CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS TO THE NORTHERN AND
WESTERN GULF TO SUPPORT A PAIR OF HIGHS...A 1020 MB HIGH NEAR
29N93W AND A 1019 MB HIGH NEAR 28N87W. A MODERATE MOIST AIRMASS
HAS BEEN MOVING ACROSS THE GULF FROM THE SW N ATLC AND THE NW
CARIBBEAN. A MID-LEVEL INVERTED TROUGH IS OVER THE EASTERN GULF
AND SUPPORTS A SURFACE TROUGH ALONG WESTERN FLORIDA COASTAL
WATERS FROM 30N84W TO 24N83W. MOISTURE AT THE LOW-MID LEVELS
ALONG WITH TROUGHINESS ALOFT SUPPORT SCATTERED HEAVY SHOWERS AND
TSTMS E OF 86W. SCATTERED SHOWERS EXTENDS INTO THE STRAITS OF
FLORIDA. ISOLATED SHOWERS/TSTMS ARE WITHIN 90 NM OFF THE
NORTHERN GULF COAST E OF 91W. OTHERWISE...THE SURFACE RIDGE IS
FORECAST TO REMAIN ANCHORED ACROSS THE NORTHERN GULF WATERS
THROUGH SATURDAY WITH LIGHT WINDS EXPECTED DURING THE WEEKEND.
TWO TROPICAL WAVES WILL MOVE INTO THE BAY OF CAMPECHE IN THE
NEXT TWO DAYS ENHANCING SHOWERS IN THE REGION.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER CENTRAL CUBA WHERE ALONG
WITH DEEP LAYER MODERATE MOIST AIR ACROSS PORTIONS OF THE NW
CARIBBEAN SUPPORT ISOLATED HEAVY SHOWERS AND TSTMS N OF 18N
BETWEEN 78W-85W. TWO TROPICAL WAVES ARE MOVING ACROSS THE BASIN.
REFER TO THE TROPICAL WAVES SECTION FOR DETAILS. DIFFLUENT FLOW
ALOFT AND A TROPICAL WAVE STARTING TO MOVE ACROSS EASTERN CUBA
SUPPORT SCATTERED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE
AND ISOLATED SHOWERS ACROSS HISPANIOLA. IN THE SW
CARIBBEAN...THIS SHOWER ACTIVITY IS BEING ENHANCED IN PART BY
THE MONSOON TROUGH AXIS MOVING ACROSS COSTA RICA AND PANAMA.
FRESH TO STRONG TRADES ARE FORECAST TO PERSIST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK.

...HISPANIOLA...
CURRENTLY SCATTERED/ISOLATED SHOWERS ARE OCCURRING ACROSS THE
ISLAND AS A TROPICAL WAVE MOVED ACROSS THE CENTRAL CARIBBEAN
SEA. AN UPPER LEVEL LOW IS ALSO CENTERED TO THE W-NW OF THE
ISLAND OVER CENTRAL CUBA AND IS PLACING HISPANIOLA WITHIN AN
AREA OF UPPER LEVEL DIFFLUENCE THAT SUPPORTS THIS CONVECTION. AS
THE WAVE PASSES TO THE WEST DURING THE NEXT 24 HOURS...THE UPPER
LEVEL LOW IS ALSO EXPECTED TO DRIFT WESTWARD AND GRADUALLY
WEAKEN IMPROVING CONDITIONS SLOWLY BY MONDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY
ALONG THE EASTERN U.S. SEABOARD THAT SUPPORTS A FRONTAL BOUNDARY
N OF THE AREA OF DISCUSSION. AN ANTICYCLONIC CIRCULATION
CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS ACROSS FLORIDA AND
PORTIONS OF THE SW N ATLC. THIS ENVIRONMENTAL PATTERN ALOFT IS
FAVORING UPPER LEVEL DIFFLUENCE WHICH ALONG MOIST AIR ON THE
REGION SUPPORT SCATTERED SHOWERS AND TSTMS N OF 22N W OF 77W AS
WELL AS FROM 19N-23N BETWEEN 70W-75W. FARTHER EAST...A MID-UPPER
LOW SUPPORT HEAVY SHOWERS AND TSTMS FROM 23N-31N BETWEEN 55W-
62W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED
NEAR 38N47W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR



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