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000
FXUS63 KGRR 111858
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
258 PM EDT TUE MAR 11 2014

LATEST UPDATE...
LONG TERM

.SYNOPSIS...
ISSUED AT 328 AM EDT TUE MAR 11 2014

A STORM SYSTEM WILL MOVE SOUTH OF THE STATE TONIGHT AND DURING THE
DAY ON WEDNESDAY. THIS WILL BRING ACCUMULATING SNOW TO THE
AREA...ESPECIALLY ACROSS SOUTHERN AREAS. MILD AIR STILL IN PLACE
TODAY WILL BE REPLACED BY COLDER AIR THAT WILL MOVE IN THROUGH THE
DAY ON WEDNESDAY. ONCE THE SNOW COMES TO AN END WEDNESDAY...DRY
CONDITIONS CAN BE EXPECTED THROUGH THURSDAY.

MILD AIR WILL RETURN TO THE AREA ON FRIDAY AHEAD OF A WEAKER SYSTEM.
A FEW RAIN AND SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT AND
SATURDAY WHEN THE WEAKER SYSTEM MOVES THROUGH.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 328 AM EDT TUE MAR 11 2014

MAIN FOCUS OF THE SHORT TERM IS OBVIOUSLY CENTERED ON THE SNOW
POTENTIAL FOR TONIGHT AND ON WED. WE HAVE EXPANDED THE WATCH
NORTHWARD TO THE I-69 CORRIDOR AS THERE HAS BEEN A SLIGHTLY
NORTHWARD TREND IN MOST OF THE 00Z MODEL DATA WITH REGARDS TO THIS
SYSTEM.

NOT TOO MANY IMPACTS TO THE AREA FOR THE TODAY PERIOD. THE INITIAL
PLAYER IN THE SCENARIO FOR THE NEXT 36 HOURS IS EVIDENT ON THE
REGIONAL RADAR IN THE FORM OF THE ECHOES /MAINLY ALOFT/ TO OUR WEST.
THIS IS THE INITIAL AREA OF MID LEVEL FGEN. IT IS MAINLY PRODUCING
CLOUDS AROUND 10K FT OR SO PER THE OBS ACROSS WI. PLENTY OF DRIER
AIR BELOW IS PREVENTING PCPN FROM REACHING THE GROUND. THIS FGEN
WILL MOVE OVER THE CWFA TODAY.

IT WILL TAKE UNTIL AFTERNOON FOR MOST OF THE AREA TO SEE PCPN REACH
THE GROUND. THIS IS WHEN ENOUGH LOWER LEVEL MOISTURE WILL DEVELOP AS
LOW LEVEL ISENTROPIC ASCENT TAKES PLACE AHEAD OF THE INCOMING LOW.
EVEN THEN THROUGH 00Z THIS EVENING...PCPN WILL GENERALLY REMAIN
LIGHT. PCPN WILL START OUT AS MAINLY LIQUID EVERYWHERE...BEFORE
STARTING TO CHANGE OVER TO SNOW ACROSS THE NORTH LATE THIS AFTERNOON
AND THEN ACROSS THE SOUTH THIS EVENING AS COLDER AIR IS DRAWN
SOUTHWARD.

PCPN COVERAGE AND INTENSITY WILL INCREASE NOTICEABLY TONIGHT...
ESPECIALLY FOR THE SECOND HALF OF THE NIGHT DOWN SOUTH. THIS OCCURS
AS THE INITIAL MID-LEVEL FGEN ACROSS WI IS DRIVEN SOUTH BY ENERGY
THAT WILL BE DIVING SOUTH QUICKLY FROM ITS CURRENT PLACEMENT ACROSS
NW CANADA. THIS WILL THEN PHASE WITH THE WAVE THAT IS CURRENTLY NEAR
UT. THE TREND SLIGHTLY NORTHWARD WITH THE SYSTEM ACROSS OUR AREA CAN
BE ATTRIBUTED TO THE NRN STREAM SYSTEM DIRECTING THE UT WAVE A
SLIGHT BIT MORE NORTH. THE HEAVIER AXIS OF SNOW WITH THE DEFORMATION
BAND THAT WAS ACROSS NRN IN AND OH NOW LOOKS TO INCH UP A LITTLE
CLOSER TO THE CWFA.

WE BELIEVE THAT THIS LOOKS LIKE A SOLID ADVISORY EVENT FOR THE WATCH
AREA. THERE IS THE POTENTIAL FOR SOME LOCAL WARNING CRITERIA SNOW
AMOUNTS TO OCCUR. FGEN BANDS ALWAYS HAVE THE POTENTIAL TO
OVER-PERFORM A BIT...AND THIS SITUATION IS NO DIFFERENT. MODEL
X-SECTIONS DOWN SOUTH FROM THE PREFERRED GFS/EURO BLEND SHOW SOME
THETA E DECREASING WITH HEIGHT...INDICATING A BETTER POTENTIAL FOR
ENHANCEMENT OF THE HEAVIER BANDS. THIS MAKES SENSE WITH THE PHASING
OF THE SYSTEMS OCCURRING NEARBY. THE BEST FORCING OCCURS JUST BELOW
THE DGZ DOWN SOUTH...WHICH COULD ALSO ASSIST IN SOME LOCALLY HIGHER
ACCUMS. WE ARE SHYING AWAY FROM THE HEAVY 00Z NAM SNOW TOTALS AS THE
UPPER FEATURES SEEM TOO STRONG WHEN COMPARED TO THE CONSENSUS OF THE
REMAINDER OF THE MODELS.

SNOW WILL TAPER OFF DURING THE DAY ON WED AS THE SYSTEM PULLS NE
AWAY FROM THE AREA. A FEW SNOW SHOWERS WILL REMAIN POSSIBLE INTO WED
AFTERNOON AS THE UPPER TROUGH AXIS MOVES THROUGH. THESE WILL END AND
SKIES WILL CLEAR AS THE FLOW BECOMES NE/OFFSHORE FOR A PERIOD BEFORE
SHORT WAVE RIDGING ALOFT AND SFC RIDGING MOVE OVERHEAD. THIS WILL
PROVIDE FOR A NEAR RECORD COLD NIGHT WED NIGHT WITH CLEARING SKIES
AND WEAKENING WINDS. SOME CLOUDS WILL INCREASE ON THU AS WE SEE WAA
ALOFT BUILD OVER THE AREA.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 257 PM EDT TUE MAR 11 2014

NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. A CLIPPER SYSTEM
MOVING ACROSS THE AREA FRIDAY WILL WILL ALLOW TEMPERATURES TO
REBOUND TO NEAR SEASONAL VALUES DURING THE DAY. THIS WILL BE
FOLLOWED BY A SHOT OF LAKE EFFECT SNOW FRIDAY NIGHT INTO EARLY
SATURDAY NORTH OF INTERSTATE 96 WITH LITTLE ACCUMULATIONS EXPECTED.

AFTER THIS...HIGH PRESSURE AT THE SURFACE FOLLOWED BY RIDGING ALOFT
KEEPS CERTAINTY FAIRLY HIGH FOR DRY WEATHER LASTING INTO MONDAY.

TUESDAY CURRENTLY LOOKS MILD AND WET WITH BOTH THE ECWMF AND GFS
BRINGING A DEEP PHASED UPPER TROUGH TOWARDS THE AREA WITH AN ATTENDANT
SURFACE LOW. HOWEVER...THIS IS NOT SUPPORTED AS MUCH BY THE 11/00Z
FIM...AND FORECAST CERTAINTY IN GENERAL DROPS OFF VERY QUICKLY 6
TO 7 DAYS OUT.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 121 PM EDT TUE MAR 11 2014

LIGHT RAIN AND MVFR CONDITIONS SHOULD DEVELOP TOWARD EVENING ACROSS
THE REGION. TEMPS WILL COOL AND THE RAIN WILL SWITCH TO SNOW
AROUND MIDNIGHT IN MOST AREAS. THIS WILL REDUCE CONDITIONS INTO THE
IFR RANGE. THE STEADIEST SNOW IS EXPECTED ALONG THE I-94 TAF SITES
WHERE A LONGER PERIOD OF IFR OR LIFR IS EXPECTED. CONDITIONS WILL
IMPROVE INTO THE MORNING HOURS OF WED...HOWEVER NORTHERLY WINDS
WITH GUSTS TO 25 KTS CAN BE EXPECTED.


&&

.HYDROLOGY...
ISSUED AT 306 PM EDT MON MAR 10 2014

RUNOFF IN THE UPPER TRIBUTARIES OF THE RIVERS IN SOUTHWEST MI IS
INCREASING AS TEMPERATURES ARE IN THE 40S WHICH IS MELTING SOME
SNOW. WE HAVE SEEN SWE VALUES DROPPING OFF AT THE OBSERVATIONAL
SITES THIS AFTERNOON. RUNOFF WILL CONTINUE INTO TUE...SO WATER
LEVELS WILL BE RISING AT THE GAGING SITES. AT THIS TIME WE ARE NOT
EXPECTING IMPACTS FROM THIS RISE...HOWEVER WITH ICE IN THE RIVERS
THAT RAISES UNCERTAINTY. WILL NEED TO MONITOR TRENDS THROUGH THE
WEEK. ARCTIC AIR MOVES IN FOR WED...WHICH SHOULD LOCK UP THE
RUNOFF FOR A FEW DAYS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 3 PM EDT
     WEDNESDAY FOR MIZ057>059-064>067-071-072.

     WINTER STORM WARNING FROM 11 PM THIS EVENING TO 3 PM EDT
     WEDNESDAY FOR MIZ073-074.

LM...NONE.
&&

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...TJT
AVIATION...JK
HYDROLOGY...MJS