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002
FXCA62 TJSJ 230154 CCA
AFDSJU

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
952 PM AST WED OCT 22 2014

.UPDATE...MINOR CHANGES WERE INTRODUCED TO SHORT TERM GRIDS TO
MATCH CURRENT CONDITIONS. OVERALL...FORECAST PACKAGE ON TRACK.

A GENERALLY FAIR AND MAINLY STABLE WEATHER PATTERN IS EXPECTED TO
PREVAIL OVER THE NEXT FEW DAYS AS MID TO UPPER LEVEL RIDGE PATTERN
HOLDS ACROSS THE AREA...WITH TOMORROW AS THE DRIEST DAY OF THE
NEXT FIVE DAYS. AREAL COVERAGE OF AFTERNOON CONVECTION IS EXPECTED
TO INCREASE SOMEWHAT FRIDAY AND SATURDAY AS TROPICAL WAVE AND
ASSOCIATED MOISTURE MOVE ACROSS THE EASTERN CARIBBEAN. HOWEVER
SUBSIDENCE ALOFT AND BULK OF MOISTURE ASSOCIATED WITH THE WAVE
WELL SOUTH OF THE AREA...SHOULD LIMIT SIGNIFICANT DEVELOPMENT. A
DRIER AIR MASS WILL MOVE IN FROM THE EAST ON SUNDAY.

&&

.AVIATION...MOSTLY VFR CONDITIONS WILL PREVAIL ACROSS THE LOCAL
FLYING AREA THRU THE FCST PERIOD WITH ONLY SLIGHT CHANCE OF
PASSING -SHRA OVERNIGHT. POSSIBLE VCTS ACROSS TJMZ AND TJBQ AFTER
23/18Z. TJSJ 23/00Z INDICATED A LIGHT EASTERLY WIND FLOW ALL THE
WAY FROM THE SURFACE TO AROUND 20K FEET...BECOMING NORTHEASTERLY
AND STRONGER FROM 20-40K FEET.

&&

.MARINE...NO CHANGE TO PREVIOUS DISCUSSION.


&&

.PREV DISCUSSION... /ISSUED 324 PM AST WED OCT 22 2014/

SYNOPSIS...A TUTT EXTENDS SOUTHWEST ACROSS THE NORTHERN LEEWARDS
INTO THE EASTERN CARIBBEAN...WITH HIGH PRESSURE RIDGE ALOFT BUILDING
EASTWARD ACROSS THE DOMINICAN REPUBLIC AND INTO THE MONA PASSAGE.
THE BUILDING RIDGE IS TO CONTINUE BUILD ACROSS THE FORECAST AREA
THROUGH EARLY FRIDAY BEFORE WEAKENING. THEREAFTER...THE UPPER TROUGH
IS TO GRADUALLY STRENGTHEN ONCE AGAIN AND BECOME MORE AMPLIFIED
ACROSS THE LESSER ANTILLES OVER THE WEEKEND...AS A TUTT LOW FORMS
OVER THE ISLAND CHAIN EAST OF THE LOCAL REGION. SURFACE HIGH PRESSURE
RIDGE WILL CONTINUE TO WEAKEN AND LIFT FURTHER NORTHEAST AS A LOW
PRESSURE SYSTEM AND ASSOCIATED FRONTAL TROUGH MOVE EASTWARDS ACROSS
THE WESTERN ATLANTIC. A TROPICAL WAVE WITH AXIS NEAR 56W IS FORECAST
TO CROSS THE LESSER ANTILLES LATE THURSDAY THEN MOVE ACROSS THE
EASTERN CARIBBEAN FRIDAY THROUGH SATURDAY.

DISCUSSION...LIMITED MOISTURE AVAILABILITY...MILD SUBSIDENCE AND
UPPER LEVEL CONVERGENT PATTERN ALOFT HAS SO FAR AIDED IN SUPPRESSING
SIGNIFICANT CONVECTIVE DEVELOPMENT ACROSS THE ISLANDS. EXPECT INCREASING
SUBSIDENCE AND SLOT OF DRIER AIR TO BE FILTERED IN ACROSS THE FORECAST
AREAS OVERNIGHT THROUGH THURSDAY. THIS WILL RESULT IN MOST FAIR WEATHER
SKIES WITH ONLY A FEW EARLY MORNING PASSING SHOWERS AND DIURNAL CONVECTION
LIMITED TO MAINLY THE WEST AND NORTHWEST PORTIONS OF PUERTO RICO
AND SOME OF THE ADJACENT ISLANDS.

THE TROPICAL WAVE AND MAJORITY OF ACCOMPANYING MOISTURE IS STILL
FORECAST TO TRACK MAINLY SOUTH OF THE REGION ON FRIDAY AND SATURDAY.
AS SUBSIDENCE AND CONVERGENT PATTERN ALOFT INCREASES OVER THE
NEXT FEW DAYS...THIS SHOULD CONTINUE TO LIMIT/SUPPRESS SIGNIFICANT
MOISTURE ADVECTION AND CONVECTIVE DEVELOPMENT ACROSS THE ISLANDS.
SOME SHOWER AND THUNDERSTORMS MAY DEVELOP ACROSS THE REGIONAL
WATERS AND PARTS OF THE ISLANDS AS THE WAVE PASSES BUT SO FAR NO
SIGNIFICANT OR WIDESPREAD ACTIVITY IS EXPECTED AT THIS TIME.

LONG TERM...EARLY NEXT WEEK MODELS SUGGEST RETURN OF EASTERLY
TRADES WITH TYPICAL PASSING SHOWERS DURING THE EARLY MORNING HOURS.
LATEST GFS MODEL GUIDANCE SUGGEST INCREASING PWAT VALUES AND BETTER
CHANCE FOR SHOWERS AND THUNDERSTORM DEVELOPMENT ACROSS THE REGION
BY THE MIDDLE AND LATTER PART OF NEXT WEEK WITH THE APPROACH OF
ANOTHER TROPICAL WAVE. UNTIL THEN...LOCAL AND DIURNAL EFFECTS WILL
CONTINUE TO BE THE MAIN DRIVING FORCE FOR ISOLATED TO SCATTERED
SHOWER ACTIVITY AND ISOLATED THUNDERSTORMS EACH DAY.

AVIATION...VFR CONDITIONS WILL PREVAIL THRU THE FCST PERIOD WITH
POSSIBLE VCTS ACROSS TJMZ AND TJBQ TIL 22/23Z. SFC WINDS PREVAILING
FROM THE EAST WITH SEA BREEZE VARIATIONS UNTIL 22/23Z...WINDS
DECREASING OVERNIGHT...GENERALLY AROUND 5 TO 10 KTS. SLIGHT CHANCE
OF PASSING -SHRA OVERNIGHT ACROSS THE LOCAL AREA.

MARINE...SEAS 2-4 FEET AND WINDS 15 KNOTS OR LESS CAN BE EXPECTED
ACROSS THE REGIONAL WATERS OVER THE NEXT FEW DAYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  90  76  88 /  10  20  40  40
STT  77  89  78  88 /  20  20  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...NONE.
&&

$$

72/23






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