WPC Met Watch |
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Mesoscale Precipitation Discussion: #0269 (2016) |
(Issued at 923 AM EDT MON MAY 30 2016
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MPD Selection |
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MESOSCALE PRECIPITATION DISCUSSION 0269
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
923 AM EDT MON MAY 30 2016
AREAS AFFECTED...NE NORTH CAROLINA...SE VIRGINIA...SE MARYLAND...S
DELAWARE...EXT S NEW JERSEY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 301323Z - 301923Z
SUMMARY...CHANNEL OF MOISTURE/INSTABILITY SHOULD SUPPORT DEEP
CONVECTION WITH RATES OVER 2"/HR LIKELY. SOME MAY BE SLOW MOVING
OR WILL REPEAT LEADING POTENTIAL FLASH FLOODING
DISCUSSION...GOES-E DEPICTS A WELL DEFINED ANTI-CYCLONIC CURVATURE
OF DEEP SUBTROPICAL RIDGE WITH A WELL DEFINED EASTERN EDGE OF DEEP
MOISTURE CHANNEL DEPICTED BY ROLL CLOUDS/DEEP CONVECTION WITHIN
VISIBLE IMAGERY. FURTHER SW TROPICAL DEPRESSION BONNIE IS ALSO
CORRALLING THE WESTERN EXTENT OF THE MOISTURE WITH ACCELERATED
SELY FLOW ACROSS THE OUTER BANKS INTO NE NC/SE VA. TO THE
NORTHWEST...INCREASED WLY FLOW ALOFT FOCUSES THE CHANNEL BACK
TOWARD THE EAST WITH MODERATE EVACUATING FLOW ALOFT FROM TOWARD
THE NE ACROSS SE VA INTO THE DELMARVA PENINSULA. AS SUCH AT THE
SURFACE A WELL DEFINED BOUNDARY IS SUPPORTING POOLING OF DEEP
MOISTURE CONVERGENCE FROM NEAR AKQ TOWARD SBY IN SE MD.
RADAR/SATL IMAGERY SHOWS DEVELOPING CONVECTION ALREADY TO -60C.
THE ENVIRONMENT BASED ON THE WAL/MHX 12Z SOUNDINGS INDICATE A
SKINNY CAPE PROFILES TO 1250 J/KG WITH 5.7C/KM LAPSE RATES AND
TPWS TO 2.0...WHICH SUPPORT HIGH RAINFALL EFFICIENCY WITH WARM
CLOUD PROCESSES AS NOTED BY LACK OF LIGHTNING AND PERSONAL WX
STATION JUST NW OF JAMESTOWN REPORTING 1.4" IN THE LAST
HOUR...LIKELY TO INCREASE WITH INCREASED UPDRAFT VIGOR...WITH
RATES OVER 2"/HR POSSIBLE IN THE NEXT FEW HOURS. GIVEN PROXIMITY
TO UPPER LEVEL FEATURES...DEEP FLOW IS FAIRLY WEAK AND WOULD BE
SUPPORTIVE OF VERY SLOW MOVEMENT OF THESE CELLS MOVING NE.
FURTHER SOUTHEAST ACROSS NE NC...ONSHORE STRENGTHENING FLOW IS
LEADING TO INCREASED BANDED CONVECTION WITH SOME POTENTIAL OF
CONTINUED UPSTREAM DEVELOPMENT AS LOW LEVEL CONVERGENCE/CONFLUENCE
FROM INFLUENCES OF BONNIE AND SUBTROPICAL MOISTURE AXIS...THIS
WILL SUPPORT SOME POTENTIAL TRAINING ACROSS THE REGION...FOR SOME
LOCALIZED FLASH FLOODING CONCERNS.
THIS SETUP IS SUPPORTED BY THE LAST 3HR RUNS OF THE OPERATIONAL
AND PARALLEL NCEP HRRR RUNS AND WRF-NSSL RUNS...THOUGH FAVORING
THE HIGHER MAGNITUDE VALUES GIVEN THE MOISTURE/INSTABILITY
ENVIRONMENT.
GALLINA
ATTN...WFO...AKQ...LWX...MHX...PHI...RAH...
ATTN...RFC...MARFC...SERFC...
LAT...LON 39477426 38247492 37607541 36927581 36277568
35927547 35567541 35217552 35107590 35177621
35277675 35477703 35697722 36087746 36677771
37037763 37727723 38447663 39277518
Last Updated: 923 AM EDT MON MAY 30 2016
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