Flash Flood Warning 7, NWS JSJ

154 
WGCA72 TJSJ 131515
FFSSJU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN JUAN PR
1115 AM AST TUE APR 13 2010

PRC053-089-131525-
/O.CAN.TJSJ.FF.W.0007.000000T0000Z-100413T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LUQUILLO PR-FAJARDO PR-
1115 AM AST TUE APR 13 2010

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR FAJARDO AND
LUQUILLO MUNICIPALITIES...

DOPPLER RADAR INDICATED THAT THE HEAVY RAIN WHICH AFFECTED THIS AREA
HAD DISSIPATED OR MOVED AWAY. NO SIGNIFICANT ADDITIONAL RAINFALL IS
EXPECTED ACROSS THESE AREAS AT THIS TIME.

LAT...LON 1830 6571 1833 6574 1838 6572 1840 6570
      1837 6567 1832 6568

$$

SNELL

ADDITIONAL INFORMATION CAN BE FOUND AT /USE LOWER CASE LETTERS/:
     HTTP://WWW.WEATHER.GOV/SANJUAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
928 AM AST TUE APR 13 2010

.UPDATE...HEAVY SHOWERS NOW IN PROGRESS OVER EXTREME EASTERN
PUERTO RICO AND MODERATE SHOWERS COMING FOR SAINT THOMAS. SHOWERS
ON SOUTHEAST COAST SHOULD BE BRIEF HOWEVER. ISSUED URBAN AND SMALL
STREAM FLOOD ADVISORY FOR AMOUNTS OF UP TO 3 INCHES AND 6 HOUR
GAGE TOTAL ON WESTERN FRINGE OF PRECIPITATION AREA IS ABOVE 2
INCHES. THIS RAIN SHOULD ABATE BY NOON BUT HAVE UPDATED GRIDS TO
REFLECT CURRENT SITUATION. QPS PRODUCT DOES NOT REFLECT BEST RAIN
AREAS SINCE BASINS ARE MORE INLAND...BUT HAVE UPDATED TOTALS THERE
TOO. WESTERN PUERTO RICO'S RAIN SHOULD BEGIN AFTER NOON.

&&

.DISCUSSION...SOUNDING SHOWS VERY MOIST LOWER LEVELS AND UNSTABLE
CONDITIONS TO 45 THOUSAND FEET. SINCE GOOD MOISTURE NOW GOES TO 24
THOUSAND FEET EXPECT GOOD SHOWER ACTIVITY AND ISOLATED
THUNDERSTORMS OVER WESTERN PUERTO RICO AFTER NOON AND SOME SHOWERS
COULD OCCUR ANYWHERE IN THE AREA.

&&

.AVIATION...MORE EXTENSIVE MVFR AND MOUNTAIN OBSCURATION SHOULD BE
EXPERIENCED IN EASTERN PUERTO RICO THROUGH 13/17Z...AND AFTER
13/17Z ISLAND WIDE.

&&

.PREV DISCUSSION... /ISSUED 522 AM AST TUE APR 13 2010/

SYNOPSIS...AT MID AND UPPER LEVELS...WINDS OVER THE AREA ARE WEST
DUE TO HIGH PRESSURE SOUTHEAST OF THE WINDWARD ISLANDS AND A
PASSING TROUGH TO THE NORTH. THERE IS A STRONG JET BETWEEN 20 NORTH
AT UPPER LEVELS THAT WILL HAVE A DIRECT INFLUENCE ON THE WEATHER
THROUGH FRIDAY.

DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUED TO AFFECT THE LOCAL ATLANTIC OFF SHORE
WATERS. ALSO SCATTERED SHOWERS AFFECTED THE EASTERN PORTION OF
PUERTO RICO...CULEBRA...VIEQUES AND THE USVI. THESE SHOWERS HAVE
REMAINED CONSISTENT THROUGH THE OVERNIGHT HOURS...THEREFORE EXPECT
MORE SHOWERS TO MOVE ONSHORE AND AFFECT THE EASTERN AND SOUTHERN
PORTIONS OF PUERTO RICO.

SIGNIFICANT CHANGES IN THE WEATHER PATTERN HAVE ALREADY STARTED AS
THE SUB TROPICAL JET IS NOW SITUATED NORTH OF OUR LOCAL FORECAST
AREA. THIS FEATURE WILL BRING MID LEVEL SHORT WAVES ACROSS THE
AREA THROUGH THE INCOMING WEEKEND. THESE SHORT WAVES WILL HELP IN
THE ENHANCEMENT OF AFTERNOON CONVECTION AND OVERNIGHT SHOWERS.
THE LOCATION OF THESE SHOWERS AND THUNDERSTORMS WILL BE TRICKY AS
MODELS SUGGEST THE DEVELOPMENT OF A LOW LEVEL LOW PRESSURE
SOMEWHERE IN OUR LOCAL REGION. WIND PATTERNS GENERATED BY THIS
LOW WILL DICTATE WHERE SHOWERS WILL BE CONCENTRATED. WE BASED
THIS FORECAST ON THE LATEST RUN OF THE GFS MODEL...WHERE THE LOW
LEVEL LOW PRESSURE DEVELOPS NORTHEAST OF PUERTO RICO.

AVIATION...GENERALLY VFR CONDITIONS SHOULD PREVAIL ACROSS ALL TAF
SITES DURING THE MORNING HOURS. HOWEVER...BRIEF PERIODS OF MVFR
CONDITIONS ARE POSSIBLE ACROSS TJSJ...TISX...TIST...AND TJPS IN
PASSING SHOWERS. DURING THE AFTERNOON HOURS...MVFR CONDITIONS AND
LOCAL MOUNTAIN OBSCURATIONS ARE POSSIBLE ACROSS TJMZ...AND TJBQ
THROUGH 13/23Z.

MARINE...WINDS WILL CONTINUE TO SLIGHTLY DECREASE TODAY AND
THEREFORE SEAS WILL SUBSIDE TO BELOW SCA CRITERIA ACROSS ALL LOCAL
WATERS. MARINER SHOULD MONITOR OUR FORECAST AS DANGEROUS MARINE
CONDITIONS COULD DEVELOP AFTER THURSDAY AS A HIGH PRESSURE BUILDS
ACROSS THE REGION INCREASING THE WINDS AND SEAS ACROSS ALL THE LOCAL
WATERS. THESE FRESH TO STRONG WINDS ARE EXPECTED TO GENERATE
CONFUSED SEAS THROUGH THE WEEKEND. THIS MARINE FORECAST IS BASED ON
THE DEVELOPMENT OF THE LOW LEVEL PRESSURE DEVELOPING NE OF THE LOCAL
REGION.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  77  88  76 /  50  30  40  40
STT  85  76  86  77 /  50  50  50  40

&&

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

23/12

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
546 AM AST TUE APR 13 2010

AMZ710>745-PRZ001>013-141000-
SAN JUAN AND VICINITY-NORTHEAST-SOUTHEAST-EASTERN INTERIOR-
NORTH CENTRAL-CENTRAL INTERIOR-PONCE AND VICINITY-NORTHWEST-
WESTERN INTERIOR-MAYAGUEZ AND VICINITY-SOUTHWEST-CULEBRA-VIEQUES-
THE NEARSHORE AND OFF SHORE ATLANTIC AND CARIBBEAN COASTAL WATERS-
546 AM AST TUE APR 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE
ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS WITH ISOLATED THUNDERSTORMS ARE
POSSIBLE TODAY...WHICH COULD PRODUCE PERIODS OF HEAVY RAINFALL.
URBAN AND SMALL STREAM FLOODING ARE LIKELY...MAINLY OVER THE
WESTERN INTERIOR AND WEST SECTIONS OF PUERTO RICO.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN MOISTURE...COMBINE WITH FAVORABLE UPPER
LEVEL ATMOSPHERIC CONDITIONS ARE EXPECTED TO BEGIN DURING MID
WEEK...WHICH COULD LEAD TO EPISODES OF HEAVY RAINFALL AT ANY TIME
FROM WEDNESDAY THROUGH AT LEAST FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME. HOWEVER...COULD
BE REQUIRED AT ANY TIME DURING THIS WEEK.

AMZ715-725-VIZ001-002-141000-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
546 AM AST TUE APR 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND
THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN MOISTURE...COMBINE WITH FAVORABLE
UPPER LEVEL ATMOSPHERIC CONDITIONS ARE EXPECTED TO BEGIN DURING
MID WEEK...WHICH COULD LEAD TO EPISODES OF HEAVY RAINFALL AT ANY
TIME FROM WEDNESDAY THROUGH AT LEAST FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.
HOWEVER...COULD BE REQUIRED AT ANY TIME THIS WEEK.