| HOME | ARCHIVES | FORECASTS | IMAGERY | ABOUT NHC | RECONNAISSANCE |

Atlantic Tropical Weather Discussion (Text)



000
AXNT20 KNHC 280545
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
205 AM EDT TUE JUL 28 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...SPECIAL FEATURES...                                          
A STRENGTHENED PRESSURE GRADIENT IS NOTED ACROSS THE CENTRAL 
CARIBBEAN SEA WITH NEAR GALE TO GALE FORCE WINDS OCCURRING FROM 
11N-14N BETWEEN 72W-77W. THESE CONDITIONS ARE FORECAST TO 
DIMINISH BELOW GALE FORCE WARNING CRITERIA BY 28/1200 UTC. SEE 
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS 
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 11N26W TO 17N25W MOVING W AT 10-15 
KT. THE WAVE COINCIDES WITH BROAD AND VERY SUBTLE 700 MB 
TROUGHING BETWEEN 23W-28W WITH 850 MB RELATIVE VORTICITY FOCUSED 
NEAR THE SOUTHERN EXTENT OF THE WAVE AXIS. ISOLATED MODERATE 
CONVECTION IS FROM 05N-13N BETWEEN 21W-29W.

TROPICAL WAVE EXTENDS FROM 09N45W TO 18N46W MOVING W AT 15-20 
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 43W-
52W WITH GLOBAL MODEL INDICATED 850 MB RELATIVE VORTICITY 
STRETCHED EAST-WEST FROM 10N-12N WITHIN THE INFLUENCE OF THE LOW 
TO MIDDLE LEVEL TROUGHING. NO SIGNIFICANT CONVECTION IS 
OCCURRING WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N67W TO 18N679W MOVING W AT 20 KT. 
THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 64W-72W WITH NO 
SIGNIFICANT CONVECTION OCCURRING AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 12N84W TO 22N82W MOVING W AT 20 KT. 
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 80W-88W 
ON THE WESTERN PERIPHERY OF A MID-LEVEL RIDGE ANCHORED OVER THE 
CENTRAL ATLC NEAR 24N63W. ISOLATED MODERATE CONVECTION IS WITHIN 
75 NM EITHER SIDE OF THE WAVE AXIS.

...ITCZ/MONSOON TROUGH...                                      
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 
20N16W TO 16N18W TO 11N26W TO 09N44W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 09N44W TO 07N58W. ISOLATED 
MODERATE CONVECTION IS FROM 08N-15N BETWEEN 14W-21W.

...DISCUSSION...

GULF OF MEXICO...                                       
NORTHEAST TO EASTERLY FLOW ALOFT INFLUENCES THE GULF BASIN THIS 
EVENING ON THE SOUTHERN PERIPHERY OF A BROAD UPPER LEVEL 
ANTICYCLONIC CIRCULATION ANCHORED OVER THE LOWER MISSISSIPPI 
RIVER VALLEY REGION. WHILE PROVIDING A GENERALLY STABLE 
ENVIRONMENT ALOFT...A SURFACE WEAKNESS IN THE FORM OF A 1012 MB 
LOW CENTERED IN THE NE GULF NEAR 29N83W AND SURFACE TROUGHING 
EXTENDING GENERALLY WESTWARD FROM THE LOW TO 28N87W IS PROVIDING 
FOCUS FOR ISOLATED SHOWERS AND TSTMS. THIS ACTIVITY IS OCCURRING 
FROM 26N-29N BETWEEN 83W-86W WITH MID-LEVEL ENERGY NOTED OVER 
THE EASTERN GULF THAT CONTINUES TO PROVIDE MARGINAL LIFTING 
DYNAMICS FOR THE CONVECTION. OTHERWISE...A WEAK SURFACE RIDGE 
ANCHORED BY A 1017 MB HIGH CENTERED NEAR 24N86W WILL MAINTAIN 
GENTLE TO MODERATE ANTICYCLONIC WINDS THROUGH LATE WEDNESDAY AS 
THE HIGH DRIFTS GRADUALLY NORTHWESTWARD.

CARIBBEAN SEA...                                            
WATER VAPOR IMAGERY INDICATES MOSTLY DRY CONDITIONS ALOFT OVER 
MUCH OF THE CARIBBEAN BASIN THIS EVENING WHICH IS LIMITING ANY 
WIDESPREAD AREAS OF STRONG AND DEEP CONVECTION. HOWEVER THE 
PRESENCE OF A TROPICAL WAVE ALONG 84W IS GENERATING A FEW 
ISOLATED SHOWERS AND TSTMS WITHIN 75 NM EITHER SIDE OF THE AXIS 
AND ACROSS PORTIONS OF EASTERN HONDURAS AND NICARAGUA. 
OTHERWISE...THE PRIMARY MARINE IMPACT IS INCREASED TRADES ACROSS 
CENTRAL PORTIONS REACHING NEAR GALE TO GALE FORCE IN CLOSE 
PROXIMITY TO THE COAST OF COLOMBIA. WHILE THE GALE IS FORECAST 
THROUGH 28/1200 UTC...THE AREA OF TRADES IS EXPECTED TO PERSIST 
IN THE STRONG BREEZE TO NEAR GALE RANGE THROUGH THURSDAY.

...HISPANIOLA...                               
CURRENTLY...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PREVAIL 
ACROSS THE ISLAND FOR THE OVERNIGHT HOURS. GIVEN DRY AND STABLE 
AIR ALOFT ALONG WITH RELATIVELY CLEAR SKIES NOTED ON SATELLITE 
IMAGERY TO THE EAST...NO SIGNIFICANT DEEP CONVECTION IS EXPECTED 
ACROSS THE ISLAND THROUGH TUESDAY.

ATLANTIC OCEAN...                                           
WATER VAPOR IMAGERY INDICATED LONGWAVE TROUGHING OVER THE 
WESTERN NORTH ATLC WITH A FEW EMBEDDED SHORTWAVES NEAR THE BASE 
OF THE TROUGHING SLIGHTLY NORTH OF THE DISCUSSION BORDER...ONE 
NEAR 37N50W AND THE OTHER NEAR 36N70W. BOTH SUPPORT WEAK SURFACE 
LOWS AND FRONTS. THE FIRST LOW IS A 1016 MB LOW CENTERED NEAR 
37N48W WITH A COLD FRONT EXTENDING SW TO 30N56W THEN STATIONARY 
TO 33N61W. THE FRONT CONTINUES AS A WARM FRONT FROM THERE INTO A 
1014 MB LOW CENTERED NW OF BERMUDA NEAR 34N68W. THE ASSOCIATED 
COLD FRONT EXTENDS SW FROM THE 1014 MB LOW TO 33N73W AND BECOMES 
STATIONARY TO THE FLORIDA COAST NEAR JACKSONVILLE. ISOLATED 
SHOWERS ARE OCCURRING WITHIN 120 NM EAST OF THE FIRST COLD FRONT 
MENTIONED...HOWEVER IS RELATIVELY DRIER THAN THE DEEPER SURFACE 
LOW TO THE WEST. GIVEN THE STRONGER MIDDLE TO UPPER LEVEL 
DYNAMICS WITH THE WESTERN-MOST LOW PRESSURE AREA...WIDELY 
SCATTERED SHOWERS AND TSTMS ARE OCCURRING GENERALLY N OF 29N 
BETWEEN 60W-78W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC 
IS UNDER THE INFLUENCE OF A SURFACE RIDGE AXIS EXTENDING FROM A 
1021 MB HIGH CENTERED NEAR 26N62W TO A 1017 MB HIGH CENTERED IN 
THE SE GULF OF MEXICO NEAR 24N86W. FINALLY...THE REMAINDER OF 
THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF ANOTHER 
SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED SE OF THE 
AZORES NEAR 36N30W.

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

$$
HUFFMAN

Standard version of this page

Alternate Formats
About Alternates - E-Mail Advisories - RSS Feeds

Cyclone Forecasts
Latest Advisory - Past Advisories - About Advisories

Marine Forecasts
Latest Products - About Marine Products

Tools & Data
Satellite Imagery - US Weather Radar - Aircraft Recon - Local Data Archive - Forecast Verification - Deadliest/Costliest/Most Intense

Learn About Hurricanes
Storm Names Wind Scale - Prepare - Climatology - NHC Glossary - NHC Acronyms - Frequently Asked Questions - AOML Hurricane-Research Division

About Us
About NHC - Mission/Vision - Other NCEP Centers - NHC Staff - Visitor Information - NHC Library

Contact Us


NOAA/ National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Tuesday, 28-Jul-2015 05:45:25 UTC