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000
FXUS63 KGRR 111722
AFDGRR

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

LATEST UPDATE...
AVIATION

.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...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE MAR 11 2014

NO MAJOR SYSTEMS ARE FORECAST TO MOVE THROUGH THE REGION THROUGH THE
LONG TERM PERIOD. TEMPERATURES WILL BE A BIT UP AND DOWN WHICH IS
FAIRLY TYPICAL AS WE MOVE THROUGH SPRING IN THE GREAT LAKES.

THE FIRST MAIN FEATURE TO KEY ON IN THE EXTENDED WILL BE A CLIPPER
SYSTEM MOVING THROUGH THE NORTHERN GREAT LAKES DURING THE THURSDAY
NIGHT THROUGH FRIDAY NIGHT TIME FRAME. AT THIS POINT THINKING
THURSDAY NIGHT AND FRIDAY WILL BE MAINLY DRY WITH SOUTHWEST FLOW
PUSHING TEMPS INTO THE 40S ON FRIDAY. A COLD FRONT MOVES THROUGH
FRIDAY EVENING WHICH SHOULD BRING THE AREA CHANCES FOR RAIN CHANGING
TO SNOW FRIDAY NIGHT. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION
WITH THE LOW PASSING NORTH OF THE AREA.

HAVE SMALL POPS IN FOR SATURDAY (20 PCT) AS NORTHWEST FLOW LAKE
EFFECT LOOKS PLAUSIBLE. DELTA T/S WILL BE IN THE LOW TO MIDDLE
TEENS. MOISTURE DWINDLES THROUGH THE DAY THOUGH...SO NOT EXPECTING
MUCH. LAKE ICE IS A LIMITING FACTOR AS WELL OBVIOUSLY.

HIGH PRESSURE THEN SETTLES INTO THE GREAT LAKES FOR THE REMAINDER OF
THE WEEKEND WITH QUIET WEATHER. MONDAY LOOKS QUIET TOO...AS THE HIGH
WILL BE DRIFTING EAST AND SOUTHERLY RETURN FLOW BEGINS AHEAD OF A
DEEPENING PLAINS SYSTEM.

WARMEST DAY OF THE PERIOD WILL BE FRIDAY WITH COOLER WEATHER
SETTLING IN FOR THE WEEKEND WITH BELOW NORMAL TEMPS IN THE 20S AND
30S.

&&

.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 STORM WATCH FROM 11 PM EDT THIS EVENING THROUGH WEDNESDAY
     AFTERNOON FOR MIZ066-067-071>074.

LM...NONE.
&&

$$

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