Post by cycloneye on Jun 29, 2015 4:05:05 GMT -6
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 AM AST MON JUN 29 2015
.SYNOPSIS...UPPER LEVEL TROUGH WILL REMAIN TO THE NORTH NORTHWEST
OF THE REGION FOR THE NEXT FEW DAYS. SAHARAN AIR LAYER WILL REMAIN
OVER THE REGION UNTIL AT LEAST TUESDAY...LIMITING THE SHOWER
ACTIVITY. A TROPICAL WAVE ALONG 50 WEST THIS MORNING...WILL REACH
THE EASTERN CARIBBEAN BY TUESDAY PASSING MOSTLY SOUTH OF THE
REGION LATE TUESDAY AND WEDNESDAY
&&
.DISCUSSION...DOPPLER WEATHER RADAR INDICATED ONLY ISOLATED
SHOWERS ACROSS THE COASTAL WATERS. NOT PRECIPITATION WAS DETECTED
OVERNIGHT AND SO FAR THIS MORNING OVER LAND AREAS. A DRY AND HAZY
AIR MASS WILL CONTINUE TO ENCOMPASS THE LOCAL ISLANDS FOR THE NEXT
COUPLE OF DAYS. SAHARAN AIR LAYER WILL CONTINUE TO INHIBIT THE
DEVELOPMENT OF ANY SIGNIFICANT SHOWERS AND THUNDERSTORMS ACROSS
THE REGION UNTIL AT LEAST LATE TUESDAY. HOWEVER...THE AVAILABLE
LOW LEVEL MOISTURE...WILL COMBINE EACH AFTERNOON WITH STRONG
DAYTIME...LOCAL EFFECTS AND AIDED WITH THE UPPER TROUGH TO OUR
NORTH TO PRODUCE SOME SHOWERS ACROSS WESTERN AND INTERIOR SECTIONS
OF PUERTO RICO. A TROPICAL WAVE ALONG 50 WEST THIS MORNING IS
EXPECTED TO REACH THE EASTERN CARIBBEAN BY TUESDAY...PASSING
MOSTLY SOUTH OF THE LOCAL ISLANDS LATE TUESDAY AND WEDNESDAY. AN
EXTENSIVE SAHARAN AIR LAYER ACROSS MOST OF THE TROPICAL ATLANTIC
BASIN WILL INHIBIT THE DEVELOPMENT OF THIS TROPICAL WAVE.
HOWEVER...THE MOISTURE ASSOCIATED WITH THE WAVE...IS EXPECTED TO
COMBINE WITH THE UPPER TROUGH TO THE NORTH NORTHWEST OF THE REGION
TO INDUCE THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS
PARTS OF THE LOCAL ISLANDS AND COASTAL WATERS. AFTER THE PASSAGE
OF THE WAVE...ANOTHER ROUND OF SAHARAN DUST WILL COVER THE REGION.
&&
.AVIATION...VFR CONDS NXT 24 HOURS...AS SAHARAN DUST AND DRY AIR
ACROSS THE FLYING AREA WILL LIMIT CONVECTIVE DEVELOPMENT. SCT CU
LAYERS 020-050...NO SIG VERTICAL DEVELOPMENT. SOME HZ ALOFT ACROSS
FLYING AREA BUT VIS P6SM...SFC WINDS FM EAST AT 10 KTS OR LESS TIL
29/13Z BCM FM ENE 15-20 KTS AND GUSTY. L/LVL WNDS FM ENE 25-30 KTS
BLO FL180 THEN BACKING BCM FM W ABV FL250. NO SIG OPERATIONAL WX
IMPACTS ATTM.
&&
.MARINE...BREEZY CONDITIONS WILL CONTINUE TO PRODUCE CHOPPY SEAS
ACROSS THE LOCAL WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR
THE OFFSHORE WATERS AND LOCAL PASSAGES DUE TO SEAS UP TO 7 FEET
AND WINDS AROUND 20 KNOTS AND HIGHER GUSTS. NEAR SHORE
WATERS...MARINERS SHOULD EXERCISE CAUTION DUE TO CHOPPY SEAS UP TO
6 FT.
&&
.FIRE WEATHER...A DRYING TREND AND A SHARP DECREASE IN MOISTURE
ADVECTION IS EXPECTED TODAY WITH THE PRESENCE OF THE SAHARAN AIR
LAYER ACROSS THE REGION. PREVAILING WINDS OF 15 TO 20 MPH WITH
HIGHER GUSTS UP TO 30 MPH IN SOME AREAS ARE EXPECTED. RH VALUES
WILL DROP TO THE MID 40S AND THEREFORE...MODERATE TO HIGH FIRE
WEATHER HAZARD ARE POSSIBLE TODAY ALONG SOUTH AND SOUTHEASTERN
COASTAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 79 / 20 20 30 40
STT 89 78 90 79 / 20 30 30 40
NATIONAL WEATHER SERVICE SAN JUAN PR
406 AM AST MON JUN 29 2015
.SYNOPSIS...UPPER LEVEL TROUGH WILL REMAIN TO THE NORTH NORTHWEST
OF THE REGION FOR THE NEXT FEW DAYS. SAHARAN AIR LAYER WILL REMAIN
OVER THE REGION UNTIL AT LEAST TUESDAY...LIMITING THE SHOWER
ACTIVITY. A TROPICAL WAVE ALONG 50 WEST THIS MORNING...WILL REACH
THE EASTERN CARIBBEAN BY TUESDAY PASSING MOSTLY SOUTH OF THE
REGION LATE TUESDAY AND WEDNESDAY
&&
.DISCUSSION...DOPPLER WEATHER RADAR INDICATED ONLY ISOLATED
SHOWERS ACROSS THE COASTAL WATERS. NOT PRECIPITATION WAS DETECTED
OVERNIGHT AND SO FAR THIS MORNING OVER LAND AREAS. A DRY AND HAZY
AIR MASS WILL CONTINUE TO ENCOMPASS THE LOCAL ISLANDS FOR THE NEXT
COUPLE OF DAYS. SAHARAN AIR LAYER WILL CONTINUE TO INHIBIT THE
DEVELOPMENT OF ANY SIGNIFICANT SHOWERS AND THUNDERSTORMS ACROSS
THE REGION UNTIL AT LEAST LATE TUESDAY. HOWEVER...THE AVAILABLE
LOW LEVEL MOISTURE...WILL COMBINE EACH AFTERNOON WITH STRONG
DAYTIME...LOCAL EFFECTS AND AIDED WITH THE UPPER TROUGH TO OUR
NORTH TO PRODUCE SOME SHOWERS ACROSS WESTERN AND INTERIOR SECTIONS
OF PUERTO RICO. A TROPICAL WAVE ALONG 50 WEST THIS MORNING IS
EXPECTED TO REACH THE EASTERN CARIBBEAN BY TUESDAY...PASSING
MOSTLY SOUTH OF THE LOCAL ISLANDS LATE TUESDAY AND WEDNESDAY. AN
EXTENSIVE SAHARAN AIR LAYER ACROSS MOST OF THE TROPICAL ATLANTIC
BASIN WILL INHIBIT THE DEVELOPMENT OF THIS TROPICAL WAVE.
HOWEVER...THE MOISTURE ASSOCIATED WITH THE WAVE...IS EXPECTED TO
COMBINE WITH THE UPPER TROUGH TO THE NORTH NORTHWEST OF THE REGION
TO INDUCE THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS
PARTS OF THE LOCAL ISLANDS AND COASTAL WATERS. AFTER THE PASSAGE
OF THE WAVE...ANOTHER ROUND OF SAHARAN DUST WILL COVER THE REGION.
&&
.AVIATION...VFR CONDS NXT 24 HOURS...AS SAHARAN DUST AND DRY AIR
ACROSS THE FLYING AREA WILL LIMIT CONVECTIVE DEVELOPMENT. SCT CU
LAYERS 020-050...NO SIG VERTICAL DEVELOPMENT. SOME HZ ALOFT ACROSS
FLYING AREA BUT VIS P6SM...SFC WINDS FM EAST AT 10 KTS OR LESS TIL
29/13Z BCM FM ENE 15-20 KTS AND GUSTY. L/LVL WNDS FM ENE 25-30 KTS
BLO FL180 THEN BACKING BCM FM W ABV FL250. NO SIG OPERATIONAL WX
IMPACTS ATTM.
&&
.MARINE...BREEZY CONDITIONS WILL CONTINUE TO PRODUCE CHOPPY SEAS
ACROSS THE LOCAL WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR
THE OFFSHORE WATERS AND LOCAL PASSAGES DUE TO SEAS UP TO 7 FEET
AND WINDS AROUND 20 KNOTS AND HIGHER GUSTS. NEAR SHORE
WATERS...MARINERS SHOULD EXERCISE CAUTION DUE TO CHOPPY SEAS UP TO
6 FT.
&&
.FIRE WEATHER...A DRYING TREND AND A SHARP DECREASE IN MOISTURE
ADVECTION IS EXPECTED TODAY WITH THE PRESENCE OF THE SAHARAN AIR
LAYER ACROSS THE REGION. PREVAILING WINDS OF 15 TO 20 MPH WITH
HIGHER GUSTS UP TO 30 MPH IN SOME AREAS ARE EXPECTED. RH VALUES
WILL DROP TO THE MID 40S AND THEREFORE...MODERATE TO HIGH FIRE
WEATHER HAZARD ARE POSSIBLE TODAY ALONG SOUTH AND SOUTHEASTERN
COASTAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 79 / 20 20 30 40
STT 89 78 90 79 / 20 30 30 40