Debris Flow in Puerto Rico, May 12, 2004

PUERTO RICO AND U.S. VIRGIN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
545 AM AST WED MAY 12 2004

.DISCUSSION...
REMNANTS OF BOUNDARY AND CONTINUED LLVL CONVERGENCE CONTINUE ACROSS
THE LOCAL CARIB WATERS THIS MORNING EXTENDING ENE ACROSS THE
LEEWARDS AND INTO THE ATLANTIC. WEAKER AND MORE NARROW CONVERGENCE
LINES ALSO UPSTREAM OF THE VIRGIN ISLANDS...WITH ALL THIS TO ADVECT
INTO FORECAST AREA NEXT 12-18 HOURS AS STRONG LLVL PRESSURE GRADIENT
ACROSS THE REGION DOMINATES. THUS FAR THIS MORNING...SHOWERS HAVE
MOVED QUICKLY AND NOT CREATED MORE THAN BRIEF URBAN AND STREAM
FLOODING. UPPER LEVEL S/W TROUGH THAT MOVED THROUGH YESTERDAY LEAVES
IN ITS WAKE ZONAL FLOW ALOFT LOCALLY AND A BROAD JET EXIT REGION
OVERHEAD. THIS AIDING IN ENHANCING TOPS ACROSS THE OFF SHORE CARIB
WATERS TO 40K FT OVERNIGHT...AND SHOULD CONTINUE TO HAVE POSITIVE
INFLUENCE ON CONVECTIVE ENHANCEMENT TODAY. LLVL FLOW HAS VEERED MORE
ELY...BUT WITH ESE FLOW AT STEERING LVL WHICH SHOULD FOCUS DIURNAL
CONVECTION ACROSS P.R. WESTERN INTERIOR...AND PORTIONS OF THE NW AS
CELLS EXIT THE ISLAND. THUS HAVE SHIFTED RAIN FOCUS A BIT NORTH FROM
PREVIOUS DAYS WITH NELY FLOW. TUTT LIKE MID TO UPPER TROUGHING
FORECAST ACROSS THE ATLANTIC TO OUR NORTH NEXT COUPLE OF DAYS WILL
FURTHER DESTABILIZE THE ATMOSPHERE AND YIELD DEEP CONVECTION. LLVL
MOISTURE STILL NOT EXPECTED TO BE ABUNDANT PER LATEST GUIDANCE...BUT
WILL BE SUFFICIENT...WITH STRONG MOISTURE GRADIENT JUST TO OUR
SOUTH...AND NUMEROUS SHOWERS AND SCATTERED TSTORMS LIKELY...WITH
MORE WIDESPREAD CONVECTION ACROSS THE CARIB.

&&

.MARINE...
TRADE WIND FLOW MORE ELY TODAY...ALBEIT NOT YET DUE EAST AT THE
SURFACE...AND WILL MAINTAIN ROUGH AND CHOPPY SEAS. NO SIGNIFICANT
CHANGES EXPECTED IN MARINE CONDITIONS NEXT SEVERAL DAYS...BUT WITH
SLIGHT DECREASE IN SEAS TONIGHT AND THU BEFORE INCREASING WIND AND
SEAS FOR THE WEEKEND. SEA YOU IN THE WATER.

&&

.HYDROLOGY...
NORTH COASTAL MUNICIPIOS RECEIVED MODERATE RAINS YESTERDAY WITH ONLY
RIO CIBUCO FLOODING. HOWEVER...THINGS WILL CHANGE TODAY AS RAINS
SHIFT MORE NORTH AND ACROSS THE NORTH COASTAL RIVER BASINS...AND
AFTERNOON STREAM FLOODING LIKELY...WITH EVENING RIVER FLOODING
LIKELY ALSO MANY SYSTEMS. THESE WET AND SATURATED CONDITIONS WILL
PERSIST THROUGH THE WEEKEND...AND AFTERNOON-EVENING FLOODING LOOKS
AS THOUGH WILL BECOME A DAILY OCCURRENCE. EMERGENCY MANAGERS KEEP IN
TOUCH.

&&

.CLIMATE...
MAY IS CLIMATOLOGICALLY ONE OF THE TWO WETTEST MONTHS OF THE YEAR
ACROSS P.R. AND HAS FOLLOWED THE CALENDAR THIS YEAR. CLIMO TRENDS
ARE EXPECTED TO CONTINUE AT NORMAL THROUGH THE NEXT FEW WEEKS. WEAK
LOW LATITUDE TROPICAL WAVES HAVE BEGUN TO EXIT AFRICA IN THE PAST
FEW WEEKS...AND WILL BEGIN TO BRING SOME ENHANCED LLVL MOISTURE TO
THE CARIB SOUTH OF OUR AREA THIS WEEKEND INTO NEXT WEEK AS STEERING
LEVEL FLOW VEERS SE ACROSS THE CARIB. STLT PHOTOS AND MODEL
INITIALIZATION SUGGEST WEAK WAVES ALONG ABOUT 45W AND 30W OVERNIGHT.
TROPICAL SEASON IS JUST AROUND THE CORNER.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  84  73  84  73 /  60  40  50  60
STT  83  73  83  73 /  60  40  40  60

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
610 AM AST WED MAY 12 2004

PRZ001>013-AMZ710>750-131000-
610 AM AST WED MAY 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY...MODERATE TO STRONG EAST WINDS IN THE LOW LEVELS WILL
COMBINE WITH THE MOISTURE REMAINING FROM THE WEAK FRONTAL TROUGH
THAT LIES TO THE EAST AND SOUTH OF THE AREA TO PRODUCE SCATTERED TO
NUMEROUS SHOWERS. MOST SIGNIFICANT PROBLEM WILL BE RAINFALL
ACCUMULATIONS THIS AFTERNOON SINCE GROUND CONDITIONS ARE SATURATED
FROM PREVIOUS DAYS RAINFALL AND ANY LOCALLY HEAVY RAINS WILL CAUSE
SMALL STREAM AND RIVER LEVELS TO OVERFLOW THEIR BANKS MAINLY ALONG
THE NORTH CENTRAL FROM THE MAIN RIVERS AND NORTHEAST AND SAN JUAN
AND VICINITY FOR THE SMALL STREAMS. A SLIGHT CHANGE IN THE LOW LEVEL
WINDS TO A MORE EASTERLY DIRECTION WILL ALLOW FOR THE STRONG
WESTERLY WINDS AT THE UPPER LEVELS COMBINED WITH LOCAL EFFECTS TO
ALLOW FOR SHOWERS AND THUNDERSTORMS TO DEVELOP THIS AFTERNOON OVER
THE WEST INTERIOR.

MARINE CONDITIONS WILL CONTINUE ROUGH AND CHOPPY ALONG OFF SHORE
ATLANTIC WATERS. ELSEWHERE SMALL CRAFT SHOULD EXERCISE CAUTION
ELSEWHERE EXCEPT THE WEST WATERS.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED.

.DAYS TWO THROUGH SEVEN...

SERIES OF UPPER LEVEL DISTURBANCES WILL TRAVEL AROUND THE BASE OF AN
UPPER LEVEL TROUGH THAT WILL SETTLE JUST WEST OF PUERTO RICO ON
THURSDAY TO PROVIDE UNSTABLE CONDITIONS THROUGH FRIDAY. THIS UPPER
TROUGH WILL INTERACT WITH THE MOISTURE LEFT OVER BY THE WEAK FRONTAL
BOUNDARY TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AT NIGHT AND
DURING THE MORNING OVER THE NEXT FIVE DAYS AND ISOLATED
THUNDERSTORMS MAINLY DURING THE AFTERNOON HOURS. LOCALIZED FLASH
FLOODING AND SMALL STREAM FLOODING IS LIKELY TO CONTINUE.

A MODERATE TO FRESH WIND FLOW AND CHOPPY SEAS WILL PREVAIL ACROSS
THE LOCAL WATERS THROUGH NEXT WEEK.

VIZ001-002-AMZ710>730-131000-
610 AM AST WED MAY 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS.

.TODAY...SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE MOVE WEST
ACROSS THE U.S. VIRGIN ISLANDS AND THE TERRITORIAL WATERS THROUGH
THE NEXT 24 HOURS. SHOWERS WILL BE MORE NUMEROUS WITH ISOLATED
THUNDERSTORMS JUST NEAR AND SOUTHWEST OF ST CROIX. LIGHT TO MODERATE
RAINFALL ACCUMULATIONS ARE TO BE EXPECTED. URBAN AND GUT FLOODING
POSSIBLE IN ST CROIX.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED.

.DAYS TWO THROUGH SEVEN...

SCATTERED SHOWERS WILL CONTINUE ACROSS THE U.S. VIRGIN ISLANDS
BECOMING NUMEROUS AT TIMES DUE TO MOIST EASTERLY WIND FLOW THAT
SHOULD PERSIST INTO NEXT WEEK.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE WEB
SITE FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS AT (ALL LOWERCASE
LETTERS): HTTP://WWW.SRH.NOAA.GOV/SJU.

RM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JUAN PR
538 AM AST WED MAY 12 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0915 PM     FLOOD            VEGA ALTA               18.42N 66.32W
05/11/2004                   VEGA ALTA          PR   EMERGENCY MNGR

            RIVER CIBUCO WAS REPORTED OUT OF ITS BANKS AND FLOODING
            ROADS 620, 647, 675, 676, AND HIGHWAY 2 AT THE 690
            INTERSECTION.

&&

RM