Hydrometeorological Discussion
Issued by NWS Northeast RFC

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AGUS71 KTAR 201644
HMDTAR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE
NORTHEAST RIVER FORECAST CENTER...TAUNTON...MA
1242 PM EDT MON OCT 20 2014

*** LONG DURATION HEAVY RAINFALL EVENT SHAPING UP FOR  ***
***   NORTHERN PORTIONS OF NEW ENGLAND THIS WORK WEEK  ***

HYDROMETEOROLOGICAL DISCUSSION:
:
14Z ( 10 AM EDT ) SURFACE AND BUOY OBSERVATIONS SHOW AN AREA OF
LOW PRESSURE ACROSS THE NORTHWEST PORTION OF LAKE HURON WITH A
COLD FRONT EXTENDING SOUTHWEST TO JUST EAST OF CHICAGO ILLINOIS.
OVER THE NEXT 24 HOURS...THIS LOW WILL DROP SOUTHEAST AND THEN
REDEVELOP SOUTH OF NEW ENGLAND BY TUESDAY EVENING. AS THIS NEW LOW
DEVELOPS...UPPER LEVEL ENERGY WILL CUTOFF CAUSING THE STORM TO
MEANDER ABOUT RIGHT INTO FRIDAY NEAR OR JUST OFF THE EAST COAST OF
NEW ENGLAND.
:
NUMERICAL WEATHER PREDICTION MODELS SHOW THE BEST ATLANTIC INFLOW
AND MOIST CONVEYOR BELT TARGETING AREAS OF CENTRAL AND WESTERN
MAINE...THE MOUNTAINS OF NORTHERN NEW HAMPSHIRE AND PERHAPS THE
MOUNTAINS OF NORTHERN VERMONT IN THE WEDNESDAY THROUGH FRIDAY TIME
FRAME AND THOSE AREAS ARE LIKELY TO SEE THE HEAVIEST RAINFALL
FROM THIS SYSTEM. BASIN AVERAGE RAINFALL THROUGH 8 AM EDT THURSDAY
IS EXPECTED TO BE IN THE 2.00 - 3.00 INCH RANGE ACROSS THE
CENTRAL AND WESTERN FOOTHILLS OF MAINE SOUTH TO THE COAST WITH
ADDITIONAL HEAVY RAINFALL POSSIBLE THURSDAY INTO FRIDAY.
:
NERFC METEOROLOGISTS AND HYDROLOGISTS WILL NEED TO MONITOR THE
PROGRESS OF THIS SYSTEM CLOSELY THIS WEEK SINCE RAINFALL COULD
BECOME HEAVY ENOUGH TO PRODUCE SIGNIFICANT RISES ON AREA RIVERS
AND STREAMS...ESPECIALLY ACROSS NORTHERN NEW ENGLAND AND PERHAPS
NORTHERN NEW YORK STATE AS WELL.
:
HYDROLOGIC DISCUSSION:
:
RIVER LEVELS FOR FORECAST LOCATIONS ACROSS MOST OF NEW YORK STATE
AND NEW ENGLAND WILL CONTINUE TO RECEDE THROUGH THE MAJORITY OF
THE NEXT COUPLE DAYS. ANTECEDENT CONDITIONS ARE WETTER THAN
EARLIER IN THE MONTH WITH RECENT RAINFALL LATE LAST WEEK AND OVER
THE WEEKEND. FURTHER, EVAPOTRANSPIRATION CONTINUES TO DECLINE WITH
THE LOSS OF LEAF COVER. THUS, RISING RIVER RESPONSES ARE MORE
LIKELY TO EXCEED THE RECENT RISES OVER THE PAST WEEKEND WITH THE
ANTICIPATED PRECIPITATION AND THE INCREASED RUNOFF.
:
A FEW LOCATIONS ARE FORECAST TO RECORD SMALL RISING RESPONSES OF
LESS THAN 2 FEET BEGINNING LATER THIS EVENING AND OVERNIGHT IN
WESTERN NEW YORK STATE AS RAINFALL DEVELOPS THERE. THEN AS
RAINFALL OVERSPREADS NEW ENGLAND LATER, MORE NOTEWORTHY RISING
RESPONSES ARE EXPECTED FOR WEDNESDAY THROUGH THE END OF THE WEEK,
ESPECIALLY IN MAINE. THE PRECIPITATION AND RUNOFF MAY BE
SUFFICIENT FOR RIVER LEVELS OF RAPIDLY RESPONDING HEADWATER AND
SMALLER TRIBUTARY RIVERS TO EXCEED MINOR FLOOD LEVELS AT AN
ISOLATED RIVER FORECAST LOCATION OR TWO. MOST RIVER RISES ARE
FORECAST TO REMAIN WITHIN BANK-FULL LEVELS.
:
DRY CONDITIONS DURING THE DAY YESTERDAY AND OVERNIGHT ALLOWED
RIVER LEVELS TO CREST AND BEGIN TO RECEDE OR TO RECEDE FURTHER.
OVERALL, RIVER LEVELS RECEDED ANYWHERE FROM RAPIDLY TO SLOWLY AT
FORECAST LOCATIONS. FLUCTUATIONS OF SEVERAL FEET OCCURRED FOR
FORECAST LOCATIONS DOWNSTREAM OF DAMS OR AT LOCATIONS WITHIN THE
INFLUENCE OF THE TIDAL CYCLE.
:
ACCORDING TO THE USGS WATER WATCH WEBPAGE... 7-DAY AVERAGE
STREAMFLOWS RELATIVE TO THOSE OCCURRING HISTORICALLY FOR SUNDAY,
10/19 ARE IN THE NORMAL TO WELL ABOVE NORMAL RANGES ACROSS MOST OF
NEW YORK STATE AND NEW ENGLAND. RECENT RAINFALL AND INCREASED
RIVER FLOWS HAVE PROVIDED FOR SEVERAL LOCATIONS WITH WELL ABOVE
NORMAL FLOWS SITUATED ACROSS CENTRAL NEW YORK STATE, WESTERN MAINE
, MUCH OF NEW HAMPSHIRE AND WESTERN TO CENTRAL MASSACHUSETTS.
SEVERAL LOCATIONS IN SOUTHERN RHODE ISLAND, EASTERN MASSACHUSETTS,
AND EASTERN NEW YORK STATE RECORDED WEEKLY AVERAGE STREAMFLOWS
BELOW NORMAL LEVELS.
:
FLOOD OUTLOOK DISCUSSION:
:
THE NERFC FLOOD POTENTIAL OUTLOOK GRAPHIC INDICATES SIGNIFICANT
RIVER FLOODING IS NOT EXPECTED IN THE NORTHEASTERN UNITED STATES
DURING THE NEXT FIVE DAYS.
:
THE FLOOD OUTLOOK GRAPHIC IS AVAILABLE ON THE WEB AT:
:
HTTP://WWW.WEATHER.GOV/NERFC/FOP
:
ADDITIONAL WATER AND WEATHER RELATED INFORMATION CAN BE FOUND ON
THE NWS/NERFC HOME PAGE AT http://www.nws.noaa.gov/er/nerfc
:
$$
:
HYDROMETEOROLOGICAL DISCUSSION:       RON HORWOOD
HYDROLOGIC DISCUSSION:                ERICK BOEHMLER




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