tolakram wrote:Shear has really dropped off in the last week or so.
Yeah that's what i was saying in my last post Tolakram
, and that's why we should begin to look carefully at all these waves coming from Africa.
Whereas Cycloneye has post a nice reply from edited by the thread "Eastern Caribbean Thread=Obs / Forecasts / Daily " Weather the San Juan Weather forecast:Interesting paragraph about the tropics from the San Juan afternoons discussion.
000
FXCA62 TJSJ 271805
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
205 PM AST MON JUL 27 2009
.DISCUSSION...
A TROPICAL WAVE AND ITS ASSOCIATED MOISTURE CURRENTLY SOUTH OF
PUERTO RICO SHOULD REMAIN MOSTLY SOUTH OF THE ISLANDS AND PUSH WEST
OF THE AREA TONIGHT. AS IT DOES SO...LOOK FOR DRIER AND MORE STABLE
AIR TO BE USHERED INTO THE AREA OVERNIGHT. THEREFORE...EXPECT ONLY
NOCTURNAL WINDWARD-FACING SHORES TO BE AFFECTED BY BRIEF PASSING
SHOWER ACTIVITY OVERNIGHT.
FOR TUESDAY THROUGH THE REST OF THE WORK WEEK...EXPECT A RETURN
TO THE TYPICAL MESOSCALE-DRIVEN NOCTURNAL/DIURNAL PATTERN DOMINATING
THE WEATHER REGIME. HPC QPF GUIDANCE SHOWS A RELATIVE MINIMUM IN
PRECIPITATION THROUGH THE MIDDLE OF THE WEEK AND MODEL GUIDANCE
SHOWS A LACK OF MOISTURE FLUX CONVERGENCE ACROSS THE AREA FOR THE
REST OF THE WEEK. AS SUCH...EXPECT MOSTLY BRIEF ISOLATED PASSING
OVERNIGHT SHOWERS NEAR THE VIRGIN ISLANDS AND WINDWARD COAST OF
PUERTO RICO ALONG WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ERUPTING IN THE AFTERNOON ALONG SEABREEZE-INDUCED FRONTS AND
CONVERGENCE ZONES AROUND THE WESTERN TOPOGRAPHY OF THE PUERTO RICAN
MAINLAND. MINIMUM/MAXIMUM TEMPERATURES WILL BE KEPT AT MEX MOS GFS
LONG-RANGE GUIDANCE.
IN THE TROPICS...THE ITCZ DEPICTED ALONG AND JUST SOUTH OF 10N IN
THE TROPICAL ATLANTIC OCEAN CONTAINS TWO DISCERNIBLE WAVES EMBEDDED
WITHIN THE MEAN FLOW. AS WE APPROACH A MORE CLIMATOLOGICALLY ACTIVE
TROPICAL CYCLONE PERIOD...UPPER LEVEL WINDS HAVE BECOME SLIGHTLY
MORE FAVORABLE FOR TROPICAL DEVELOPMENT ACROSS THE EASTERN CARIBBEAN
AND WESTERN TROPICAL ATLANTIC AS STRONG UPPER-LEVEL WESTERLIES HAVE
RELAXED. CURRENT TJSJ 27/1200Z RAOB...AS WELL AS OTHER PROXIMITY
SOUNDINGS...SHOW FAIRLY LIGHT AND VARIABLE WIND PROFILES STRAIGHT
THROUGH THE COLUMN. CONVERSELY...THE MADDEN-JULIAN OSCILLATION /MJO/
CONTINUES TO HINT AT SUPPRESSED LIFT AND LACK OF UPPER LEVEL
DIFLUENCE FOR AT LEAST TWO MORE WEEKS ACROSS THE TROPICAL
ATLANTIC. MOREOVER...THE LATEST 24-MONTH RUNNING TROPICAL CYCLONE
ACCUMULATED CYCLONE ENERGY /ACE/ INDEX FOR THE NORTHERN HEMISPHERE
SHOWS THE LOWEST SUMS IN NEARLY 30 YEARS. WHAT THIS MEANS IS THAT
WHILE THE LOCAL ENVIRONMENT MAY ALLOW FOR A TROPICAL CYCLONE TO
SUSTAIN ITSELF...THE OVERALL TROPICAL ENVIRONMENT HAS PRECLUDED
ONE FROM ACTUALLY FORMING AT THIS TIME.
&&
.AVIATION...
PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL ISLANDS
AND AT ALL LOCAL TAF SITES FOR THE NEXT 18 TO 24 HOURS. EAST WINDS
AVERAGING 10 TO 20 KNOTS WITH OCCASIONAL GUSTS UP TO 30 KNOTS
ALONG COASTAL AREAS ARE EXPECTED UNTIL NOW THROUGH THE EVENING
HOURS.
http://forecast.weather.gov/product.php ... glossary=1
