Flash Flood Guidance
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8
000
AWUS01 KWNH 231217
FFGMPD
MEZ000-MAZ000-NHZ000-VTZ000-231700-

MESOSCALE PRECIPITATION DISCUSSION 0429
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
816 AM EDT THU OCT 23 2014

AREAS AFFECTED...MA...SOUTHEAST NH...SOUTHERN ME

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 231200Z - 231700Z

SUMMARY...SHORT-TERM FLASH FLOODING WILL CONTINUE TO BE A CONCERN
FOR THE MORNING HOURS AT LEAST LOCALLY.

DISCUSSION...A DEEP CLOSED LOW OFFSHORE OF SOUTHERN NEW ENGLAND
THIS MORNING CONTINUES TO FUNNEL DEEP ATLANTIC MOISTURE INLAND
ACROSS PORTIONS OF THE NORTHEAST. A WELL-DEFINED MID LEVEL
DEFORMATION ZONE AS DENOTED IN WV IMAGERY IS INTERACTING WITH THIS
DEEP ATLANTIC FETCH AND IS FOSTERING NUMEROUS BANDS OF HEAVY RAIN
WHICH WRAPPING WESTWARD AROUND THE NORTH SIDE OF THE UPPER LOW.

THE LATEST IR SAT IMAGERY INDICATES THERE ARE STILL SOME COOLER
CLOUD TOP CLUSTERS OFFSHORE AND THERE IS SUFFICIENTLY DIVERGENT
FLOW ALOFT THAT THESE CLUSTERS OF HEAVIER RAIN SHOULD REMAIN
ORGANIZED ENOUGH TO SUSTAIN THE HEAVY RAINFALL THREAT ACROSS
PORTIONS OF SOUTHERN AND EASTERN NEW ENGLAND THROUGH THE MORNING
HOURS.

VAD WIND PROFILER DATA IN THE H85/H925 LAYER INDICATES A ROBUST
LOW LEVEL JET CRASHING INTO COASTAL AREAS OF NORTHEAST
MA...COASTAL NH AND SOUTHERN ME...WITH 40 TO 50 KTS OF ATLANTIC
FETCH SUPPORTING MOISTURE FLUX ANOMALIES OF OVER 3 STD DEV ABOVE
NORMAL. THE 00Z ARW AND 00Z NMMB SUPPORT THIS AXIS OF ENHANCED
MOISTURE TRANSPORT GRADUALLY SHIFTING NORTH UP THE NEW ENGLAND
COAST...WITH MORE EMPHASIS BY MIDDAY ACROSS EASTERN AND SOUTHERN
ME.

ONGOING FLOODING CONCERNS ACROSS NORTHEAST MA SHOULD THEREFORE
IMPROVE AS THE BANDS OF HEAVIER RAIN SHIFT FARTHER NORTH WITH
TIME. HOWEVER...THE POTENTIAL FOR LOCALLY SIGNIFICANT RUNOFF
PROBLEMS/FLASH FLOODING WILL PERSIST AT LEAST THROUGH MIDDAY
ACROSS SOUTHEAST NH AND MAY TEND TO INCREASE IN NATURE FOR
ESPECIALLY SOUTHERN ME BASED ON LATEST SAT/RADAR TRENDS AND GIVEN
SUCH A PRONOUNCED LOW LEVEL JET. EXPECT ADDITIONAL RAINFALL
AMOUNTS OF 2 TO 3 INCHES...AT LEAST LOCALLY THROUGH MIDDAY WHERE
THE MORE PRONOUNCED BANDS SET UP.

ORRISON

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ALY...BOX...GYX...

ATTN...RFC...NERFC...

LAT...LON   44267014 44246910 43936894 43496958 43107020
            42717031 42136993 42187095 42067223 42147281
            42567280 43117203



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.