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SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 07/29/07 2100Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-763-8678
LATEST DATA USED: GOES-12 2045Z GG
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LOCATION...SE MARYLAND...NE VIRGINIA...
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ATTN WFOS...AKQ...LWX...
ATTN RFCS...MARFC...
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EVENT...SLOW MOVING THUNDERSTORMS
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SATELLITE ANALYSIS AND TRENDS...VISIBLE LOOP CONTINUES TO SHOW VERY
STRONG THUNDERSTORMS ACROSS SE MD MOVING INTO THE VA PORTION OF THE
DELMARVA. THOUGH THE TOPS HAVE NEVER BEEN VERY COLD WITH THESE CELLS THE
VISIBLE IMAGERY PRESENTATION WITH MULTIPLE OVERSHOOTING TOPS AND VERY
STARK/HARD EDGES TO THE ANVILS INDICATE CONTINUED VERY STRONG UPDRAFTS
WHICH ARE SUPPORTED BY VERY GOOD LOW LEVEL DEEP MOISTURE CONVERGENCE
PARTICULARLY WITH SEA BREEZE INTERACTIONS. PWS IN THE AREA STILL ARE
VERY HIGH WITH VALUE IN THE 1.9" RANGE...SO RATES WILL BE VERY HIGH
OVER 2.0"/HR...AND WITH SOME OF THE IMPRESSIVE OVERSHOOTING TOPS LIKE
THOSE AT 2000Z OVER NE SOMERSET COUNTY...COULD REACH VALUES OVER 3"/HR.
CORFIDI VECTORS AND NOW LONG DURATION OF THUNDERSTORM COMPLEX CLEARLY
SHOW VERY LIMITED PROPAGATION VECTORS SO CELLS ARE VERY SLOW MOVING AND
TEND TO SHIFT DUE TO COLD POOL/OUTFLOW ADVANCEMENT RATHER THAN LARGER
SCALE FLOW.  THIS OUTFLOW MOTION NATURE HAS LEAD TO STATIONARY CELLS
AND SATELLITE ESTIMATES OF 4-5" OVER WICOMICO COUNTY IN S MD SINCE THERE
WERE SOME MERGERS AS WELL.  NEW CELL OVER N ACCOMACK COUNTY APPEARS TO
BE ADVANCING TOWARD S SOMERSET OVERSHOOTING CELL...SO S SOMERSET MAY BE
SET FOR NEXT AREA OF EXTREME TOTALS.

N VA... LARGE COMPLEX OVER N VA/DC AREA HAS SENT OUTFLOW BOUNDARY OUT IN
S/SW/W DIRECTIONS.  VIS LOOP HAS SHOWN GOOD CU BANDS THROUGHOUT THE DAY
MOVING NORTHWARD ACROSS ALL OF VA...DEVELOPMENT OVER HANOVER/HENRICO
COUNTIES ALSO AIDED THIS SOUTHERLY FLOW BY SENDING OUT AN OUTFLOW
BOUNDARY.  CURRENTLY THE TWO OUTFLOWS HAVE MERGED AND RAPIDLY DEVELOPED
A LINE OF STRONG THUNDERSTORMS BETWEEN THE POTOMAC AND RAPPAHANNOCK
RIVERS. THIS ALONG WITH FLOW UP THE RIVERS IN RESPONSE TO THE DEVELOPING
CONVECTION... THESE CELLS HAVE REACHED -60C TO -65C TOPS WHICH ARE COOLER
THAN SURROUNDING CELLS DUE TO THEIR VIGOR... AND SO RATE IN EXCESS OF
3"/HR ARE POSSIBLE.  CELL MOTION SHOULD ALSO BE STATIONARY SINCE THE
OUTFLOWS WERE MERGING AT 180 DEGREES AND STATED BEFORE UPPER LEVEL FLOW
DOES NOT SUPPORT CELL MOTION GREATER THAN 5KTS.
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SEE NCEP HPC DISCUSSION AND QPF/S FOR FORECAST.
....NESDIS IS A MEMBER OF 12 PLANET....
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SSD/SAB WEB ADDRESS FOR PRECIP ESTIMATES:
HTTP://WWW.SSD.NOAA.GOV/PS/PCPN/
...ALL LOWER CASE EXCEPT /PS/PCPN/
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LAT...LON 3837 7503 3784 7507 3789 7767 3826 7759
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