Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 151927
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
327 PM EDT WED APR 15 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/FIRE WEATHER/HYDRO/MARINE

.SYNOPSIS...
ISSUED AT 313 PM EDT WED APR 15 2015

HIGH PRESSURE OVER NEW ENGLAND WILL RESULT IN A SOUTHERLY FLOW
OF MILD AIR HERE IN THE GREAT LAKES REGION TONIGHT AND THURSDAY.
A WEAK WAVE OF LOW PRESSURE WILL TRACK IN FROM THE SOUTH OVERNIGHT
RESULTING IN SOME SHOWERS AND EVEN A THUNDERSTORM INTO THURSDAY.
A DRIER AIRMASS ARRIVES FOR FRIDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 313 PM EDT WED APR 15 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE PRECIPITATION
AND THUNDER RISK TONIGHT INTO THURSDAY.

SOME OF THE MODELS...NAM AND GFS...SHOW ELEVATED INSTABILITY
MOVING IN FROM THE SOUTH TONIGHT AND THURSDAY MORNING.
ACCOMPANYING THIS INSTABILITY WILL BE A LOW LEVEL JET...CAUSING
SOME LIFT BELOW THE UNSTABLE LAYER. THUS A RISK EXISTS FOR
THUNDERSTORMS BASED OFF THESE MODELS. WILL KEEP THE MENTION GOING
FOR THURSDAY...BUT WILL NEED TO MONITOR THE POSSIBILITY OF ADDING
IT TO TONIGHTS FORECAST. I DID RAISE POPS TONIGHT AND THU GIVEN
THE BETTER AGREEMENT THAT PRECIPITATION WILL MOVE IN.

POPS WERE DOWNPLAYED FOR THU NIGHT AS THE DEEPER MOISTURE PUSHES
EAST. DRY AIR ADVECTION PERSISTS INTO FRIDAY...SO DRY WEATHER WILL
BE FORECASTED.

ABOVE NORMAL TEMPERATURES EXPECTED THROUGH THE PERIOD WITH A MILD
SOUTHERLY FLOW PERSISTING.


.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 313 PM EDT WED APR 15 2015

EXTENDED MODELS CONTINUE THE TREND OF BRINGING A COLD FRONT AND
ASSOCIATED PRECIPITATION THROUGH THE REGION SUNDAY AFTERNOON. A
CANADIAN AIRMASS WILL THEN SPREAD SOUTH AND TEMPERATURES WILL FALL
BELOW NORMAL FROM TUESDAY EVENING.  MODEL DATA INDICATES THE
POTENTIAL FOR SNOW TO BE MIXED WITH RAIN ACROSS NORTHERN PORTIONS OF
THE REGION TUESDAY NIGHT INTO WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 138 PM EDT WED APR 15 2015

GUSTY EAST WINDS WILL CONTINUE AT ALL TAF SITES IN WRN MICHIGAN
THROUGH THIS EVENING AS NEXT STORM SYSTEM APPROACHES. VERTICAL
PROFILES OF MOISTURE SUGGEST A RAPID LOWERING OF CEILINGS AFTER
MIDNIGHT...WITH RAIN CHANCES INCREASING TOWARD MORNING. SMALL
AMOUNTS OF ELEVATED CAPE AND INSTABILITY MOVE THROUGH AROUND
DAYBREAK TOMORROW...BUT WILL LEAVE THUNDER OUT OF THE TAFS FOR
NOW.


&&

.MARINE...
ISSUED AT 313 PM EDT WED APR 15 2015

IMPACTS TO MARINERS LOOKS LIMITED INTO FRIDAY. WINDS THIS EVENING
WILL BE UP OVER 15 KNOTS AT TIMES. ALSO WITH A SMALL RISK FOR
THUNDER...THAT COULD RESULT IN SOME HAZARDS.

&&

.FIRE WEATHER...
ISSUED AT 313 PM EDT WED APR 15 2015

ELEVATED FIRE DANGER RISK CONTINUES THIS EVENING WITH VERY LOW HUMIDITY
VALUES...GUSTY EAST WINDS AND TEMPERATURES IN THE 60S. LESS OF A
RISK WILL EXIST ON THURSDAY AS MOISTURE MOVES IN FROM THE SOUTH.

&&

.HYDROLOGY...
ISSUED AT 313 PM EDT WED APR 15 2015

UP TO A HALF INCH OF RAIN IS FORECASTED FOR TONIGHT AND THU...MOST
LOCATIONS SHOULD SEE UNDER A QUARTER INCH. THIS SHOULD RESULT IN
MINIMAL IMPACTS TO THE RIVERS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...MWS
AVIATION...MWS
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS





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