614
FXUS04 KWBC 032049
QPFPFD
QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
448 PM EDT SUN JUN 03 2018
PRELIM DAY 1, DAY 2 AND DAY 3 QPF DISCUSSION
VALID JUN 04/0000 UTC THRU JUN 07/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR
..MID ATLANTIC/NORTHEAST/GREAT LAKES/OHIO VALLEY
A MEANDERING LOW OVER CENTERED OVER EASTERN VIRGINIA WILL CONTINUE
TO SUPPORT AREAS OF MODERATE TO HEAVY PRECIPITATION ACROSS
PORTIONS OF THE MID ATLANTIC THROUGH THE REMAINDER OF THE
AFTERNOON INTO THE EVENING HOURS. DEEP SATURATION THROUGH THE AIR
COLUMN CONTINUES TO SUPPORT VERY EFFICIENT RAIN PROCESSES, WITH
SOME AREAS CONTINUING TO SEE HEAVY AMOUNTS ACCUMULATE QUICKLY. THE
HEAVY RAINFALL THREAT IS STILL EXPECTED TO DIMINISH THIS EVENING
AS A UPSTREAM TROUGH MOVING ACROSS THE GREAT LAKES BEGINS TO DRIVE
THE LOW OFFSHORE.
THIS LOW IS EXPECTED TO MOVE OFF OF THE MID ATLANTIC COAST
OVERNIGHT, WITH THE MODELS IN GENERALLY GOOD AGREEMENT TAKING THE
SYSTEM SOUTH OF NEW ENGLAND ON MON. STRONG SOUTHERLY LOW LEVEL
FLOW AHEAD OF THE LOW IS EXPECTED TO DIRECT A PLUME OF DEEP
MOISTURE INTO COASTAL SOUTHERN NEW ENGLAND ON MON, WITH THE GFS
SHOWING PWS INCREASING TO AROUND 2 INCHES ON MON. THIS MOISTURE
INTERACTING THE WITH FAVORABLE UPPER DYNAMICS AHEAD OF AN UPSTREAM
LOW CLOSING OFF OVER SOUTHEASTERN CANADA, IS EXPECTED TO SUPPORT
SOME MODERATE TO HEAVY RAINS ACROSS SOUTHEASTERN NEW ENGLAND.
INCREASING INSTABILITY AND DEEPENING MOISTURE AHEAD OF THE
AFOREMENTIONED UPPER TROUGH AND ITS ASSOCIATED COLD FRONT SHOULD
CONTINUE TO SUPPORT DEVELOPING SHOWERS AND THUNDERSTORMS ACROSS
THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS THIS AFTERNOON, WITH
ENHANCED DIVERGENCE AHEAD OF THE UPPER TROUGH SUPPORTING A GREATER
THREAT FOR HEAVY AMOUNTS ACROSS EASTERN OHIO INTO WESTERN
PENNSYLVANIA AND WEST VIRGINIA THIS AFTERNOON. AS THE FRONT
PUSHES FURTHER EAST INTO A MORE STABLE AIRMASS, RAINFALL RATES ARE
EXPECTED TO DIMINISH WHILE THE SYSTEM MOVES ACROSS CENTRAL TO
EASTERN PENNSYLVANIA AND NEW YORK OVERNIGHT. HOWEVER, THE
MOISTURE AND FORCING AHEAD OF THE FRONT MAY BE SUFFICIENT ENOUGH
TO PRODUCE MODERATE TO LOCALLY HEAVY AMOUNTS, ESPECIALLY ACROSS
PORTIONS OF UPSTATE NEW YORK.
..SOUTHERN ROCKIES/PLAINS
SOUTHWESTERLY FLOW AHEAD OF SHORTWAVE TROUGH MOVING INTO THE FOUR
CORNERS REGION CONTINUES TO MOISTEN THE MID LEVELS ACROSS NEW
MEXICO AND SOUTHERN COLORADO AS SOUTHEASTERLY WINDS BEHIND A COLD
FRONT THAT HAS SETTLED SOUTHWEST INTO WEST TEXAS BEGIN CHANNEL LOW
LEVEL MOISTURE INTO THE REGION. THIS WILL CONTINUE TO SUPPORT
DEVELOPING STORMS ACROSS THE MOUNTAINS BEFORE SPREADING EAST INTO
THE HIGH PLAINS THIS AFTERNOON AND EVENING. WITH PW ANOMALIES
INCREASING TO 2-3 STANDARD DEVIATIONS ABOVE NORMAL, THERE REMAINS
A GOOD MODEL SIGNAL FOR LOCALLY HEAVY ACCUMULATIONS THIS AFTERNOON
AND EVENING FROM THE SOUTHERN COLORADO AND NEW MEXICO RANGES
SOUTHEASTWARD INTO THE ADJACENT HIGH PLAINS OF EASTERN NEW MEXICO
AND WEST TEXAS. FORECAST CONFIDENCE DIMINISHES OVERNIGHT AS THE
HI-RES MODELS SHOW SIGNIFICANT SPREAD WITH RESPECT TO HOW QUICKLY
CONVECTION DIMINISHES AS IT MOVES FURTHER EAST INTO CENTRAL TEXAS.
WHILE THE NAM CONEST SHOWS WIDESPREAD MODERATE TO LOCALLY HEAVY
AMOUNTS SPREADING EAST INTO CENTRAL TEXAS, THE HWR-NMMB SHOWS
CONVECTION DIMINISHING MUCH SOONER WITH ONLY SCATTERED LIGHT
AMOUNTS. WPC QPF REFLECTS A COMPROMISE SIMILAR TO THE HREF MEAN,
MAINTAINING AT LEAST SOME LIGHT TO MODERATE AMOUNTS ALONG AN AXIS
OF DEEPER MOISTURE AND GREATER INSTABILITY ACROSS CENTRAL TEXAS.
AS THE AFOREMENTIONED SHORTWAVE CONTINUES TO MOVE EAST, MODELS
CONTINUE TO DIFFER LATE IN THE PERIOD WITH POSSIBLE CONVECTIVE
REDEVELOPMENT ACROSS CENTRAL INTO SOUTHEAST TEXAS, WITH THE NAM
CONEST THIS TIME BEING THE MUCH DRIER SOLUTION. WITH LIMITED
CONFIDENCE, CONTINUED TO FOLLOW THE HREF MEAN THROUGH THE END OF
THE PERIOD.
DAY 2
..NORTHERN NEW ENGLAND
NO SIGNIFICANT CHANGES MADE TO THE PREVIOUS WPC QPF ACROSS
NORTHERN TO EASTERN PORTIONS OF NEW ENGLAND WITH THE COMMA
HEAD/DEFORMATION PRECIP REGION TO THE NORTHWEST OF THE SURFACE LOW
MOVING NORTHEAST FROM OFF THE SOUTHEAST NEW ENGLAND COAST TO SOUTH
OF NOVA SCOTIA. ASIDE FROM SOME MINOR TIMING DIFFERENCES---MODEL
CONSENSUS IS FOR MODERATE PRECIP TOTALS OVER NORTHERN PORTIONS OF
NEW ENGLAND AND MODERATE TO HEAVY OVER EASTERN PORTIONS OF MAINE.
...UPPER MS VALLEY---LOWER GREAT LAKES---UPPER OH VALLEY---CENTRAL
APPALACHIANS INTO THE MID-ATLANTIC...
IN THE WAKE OF THE LOW MOVING OFF THE NEW ENGLAND COAST DAY 2--- A
SECONDARY COLD FRONT WILL DROP SOUTHWARD THROUGH THE GREAT LAKES
AND TOWARD THE OHIO VALLEY. ADDITIONAL PRECIPITATION LIKELY AHEAD
OF THIS FRONT FROM THE UPPER MS VALLEY---ACROSS THE LOWER GREAT
LAKES AND INTO THE UPPER OH VALLEY---CENTRAL APPALACHIANS INTO THE
MID-ATLANTIC. GENERALLY LIGHT TO MODERATE TOTALS EXPECTED---WITH
UPSLOPE INTO THE CENTRAL APPALACHIANS SUPPORTING LOCALLY HEAVY
AMOUNTS HERE.
DAYS 2 & 3
..NORTHERN PLAINS INTO THE UPPER MS VALLEY
SHORTWAVE ENERGY PUSHING EAST NORTHEAST INTO THE NORTHERN HIGH
PLAINS LATE DAY 2 WILL BEGIN TO STRENGTHEN THE LOW LEVEL SOUTHERLY
INFLOW INTO THE ASSOCIATED FRONTAL BOUNDARY PUSHING INTO THE
NORTHERN PLAINS. THIS WILL BEGIN TO INITIATE CONVECTION IN THE
VICINITY OF THIS FRONT LATE TUESDAY AFTERNOON---WITH THIS ACTIVITY
LIKELY BECOMING WELL ORGANIZED TUESDAY NIGHT INTO EARLY WEDNESDAY
AS IT PUSHES ACROSS PORTIONS OF THE NORTHERN PLAINS AND TOWARD THE
UPPER MS VALLEY. HEAVIEST TOTALS LIKELY DURING THE DAY 3 TIME
PERIOD WITH MODERATE TO HEAVY AMOUNTS DEPICTED ACROSS CENTRAL TO
EASTERN ND---NORTHERN SD INTO MUCH OF MN AND WESTERN WI. THIS
ACTIVITY LIKELY WILL WEAKEN AFTER 1200 UTC WEDNESDAY BUT MAY AGAIN
RE-FIRE LATE WEDNESDAY AFTERNOON. CONVECTION EXPECTED TO BE
FAIRLY PROGRESSIVE WITH ONLY A MARGINAL RISK DEPICTED FOR THE DAY
3 EXCESSIVE RAINFALL OUTLOOK...12Z TUE-12Z...WED OVER CENTRAL TO
EASTERN ND INTO NORTHWEST MN.
..SOUTHERN PLAINS TOWARD THE LOWER MS VALLEY
ORGANIZED CONVECTION POTENTIAL WILL CONTINUE DAY 2 ALONG THE
FRONTAL BOUNDARY LIFTING SLOWLY NORTHWARD ACROSS CENTRAL TX.
SOUTH TO SOUTHWESTERLY LOW LEVEL FLOW INTO THIS FRONT WILL SUPPORT
ADDITIONAL ORGANIZED CONVECTION PUSHING SOUTHEAST ACROSS SOUTHERN
OK/NORTHERN TX MONDAY NIGHT INTO EARLY TUE AND TOWARD THE LOWER MS
VALLEY LATER TUESDAY. ANY REMAINING ACTIVITY ALONG THIS FRONT DAY
3 EXPECTED TO BE CONFINED TO THE CENTRAL GULF COAST/LOWER MS
VALLEY REGION WITH MODERATE TO LOCALLY HEAVY TOTALS POSSIBLE.
..CENTRAL TO SOUTH FLORIDA
THE EASTERN EXTENT OF THE FRONT OVER THE SOUTHERN PLAINS WILL BE
VERY SLOW MOVING OVER CENTRAL FLORIDA---FOCUSING AN AXIS OF ABOVE
AVERAGE PW VALUES ALONG AND TO ITS SOUTH OVER CENTRAL TO SOUTH
FLORIDA BOTH DAY 2 AND 3. THIS WILL SUPPORT MODERATE TO HEAVY
PRECIP TOTALS ALONG AND SOUTH OF THIS FRONT DAYS 2 AND 3 FOR
CENTRAL TO SOUTH FLORIDA.
PEREIRA/ORAVEC
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML
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