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000
FXUS63 KGRR 170416
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1216 AM EDT MON MAR 17 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 325 PM EDT SUN MAR 16 2014

A LARGE CANADIAN POLAR HIGH PRESSURE SYSTEM WILL BE OVER MICHIGAN
TONIGHT. EXPECT ANOTHER CLEAR COLD NIGHT WITH TEMPERATURES FALLING
BELOW ZERO NEAR AND NORTH OF INTERSTATE 96. AS THE HIGH MOVES AWAY
FROM THE AREA MONDAY EXPECT A WARMING TREND WITH HIGHS NEAR 30.

A STRONG STORM WILL CROSS LOWER MICHIGAN TUESDAY NIGHT INTO
WEDNESDAY BRINGING A SURGE OF WARM AIR TUESDAY INTO EARLY WEDNESDAY.
THIS WILL LEAD TO ADDITIONAL SNOW MELT AND RIVER RISES BUT NOT
DANGEROUSLY SO. THEN AN AREA OF RAIN WILL WITH GUSTY SOUTH WINDS
WILL CROSS LOWER MICHIGAN TUESDAY NIGHT AHEAD OF THE OCCLUDED FRONT.
ONCE THE FRONT COMES THROUGH DURING THE DAY WEDNESDAY EXPECT VERY
STRONG GUSTY WINDS WITH RAIN SHOWERS CHANGING TO SNOW SHOWERS
DURING THE AFTERNOON. ONLY A LIMITED ACCUMULATION IS EXPECTED WITH
THIS SNOWFALL. TEMPERATURES WILL FALL INTO THE 30S DURING THE
AFTERNOON. SNOW SHOWERS WILL DIMINISH WEDNESDAY NIGHT.

ANOTHER STORM SYSTEM LATE IN THE WEEK COULD BRING MEASURABLE SNOW
TO THE AREA AND COLDER TEMPERATURES.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 325 PM EDT SUN MAR 16 2014

TONIGHT SHOULD BE ANOTHER ONE OF THOSE NIGHTS WITH CLEAR SKIES AND
LIGHT WINDS NEAR THE GROUND. WITH THE LOW LEVEL WIND MOSTLY
NORTHEAST TO EAST I WOULD EXPECT THE COLDEST AIR TO GET CLOSE TO
THE LAKE SHORE AREAS TOO. AS ALWAYS AREAS NEAR ROUTE 10 WILL HAVE
THE COLDEST LOW TEMPERATURES. VALLEY AREAS COULD SEE TEMPERATURES
NEAR -15 OR EVEN COLDER.

THE HIGH MOVES TO THE EAST MONDAY AS THE POLAR JET CORE CROSSES
THE AREA DURING THE DAY. ONCE THAT HAPPENS... THE CORE OF COLD AIR
ALOFT WILL HAVE MOVED EAST OF OUR AREA. THIS WILL LEAD TO ANOTHER
COLD DAY MONDAY WITH HIGHS JUST BELOW FREEZING BUT STILL NEARLY 10
DEGREES WARMER THAN TODAY.

THE SYSTEM COMING INTO THE AREA TUESDAY NIGHT HAS REALLY STRONG
DYNAMICS. THE UPPER LEVEL SYSTEM GOES NEGATIVE TILT AND THERE IS A
DEEPLY CLOSED OFF UPPER LOW WITH THIS STRONGLY OCCLUDED SYSTEM. IF
NOT FOR THE PATHETIC LACK OF SIGNIFICANT MID LEVEL MOISTURE (PRECIPITABLE
WATER STRUGGLES TO REACH .7 INCHES) WE WOULD SURELY HAVE HAD
THUNDERSTORMS WITH THIS SYSTEM. THERE IS A 50 KNOT LOW LEVEL JET
AND A COUPLED UPPER LEVEL JET WITH A 130 KNOT JET EXIT REGION OVER
SOUTHWEST LOWER MICHIGAN AROUND MIDNIGHT TUESDAY NIGHT. AT THE END
OF THE DAY WHAT THIS MEANS FOR US IS WE WILL SEE A BAND OF STRONG
SHOWERS CROSS THE AREA LATE TUESDAY NIGHT WITH VERY GUSTY WINDS.

THE SURGE OF WARMER AIR AHEAD OF THE SYSTEM SHOULD BRING OUR
AFTERNOON TEMPERATURES INTO THE 40S TUESDAY AND I WOULD THINK
TEMPERATURES WILL NOT FALL MUCH TUESDAY NIGHT SO THERE IS LITTLE
OF ANY THREAT OF FREEZING PRECIPITATION TUESDAY NIGHT... EVEN OVER
THE ROUTE 10 AREA.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN MAR 16 2014

WE CONTINUE TO FOCUS ON A COUPLE OF SYSTEMS IN THE LONG TERM PORTION
OF THE FCST. ONE WILL BE AT THE BEGINNING OF THE PERIOD ON WED...AND
THE OTHER IS DURING THE FRI/FRI NIGHT TIME PERIOD. NO REAL CHANGES
HAVE BEEN MADE TO THE FCST AS MODEL GUIDANCE REMAINS FAIRLY
CONSISTENT TO PREVIOUS RUNS.

WE CONTINUE TO BASE THE FCST ON A SLIGHTLY SLOWER SOLUTION FOR THE
SYSTEM ON WED...CLOSER TO THE EURO HANDLING OF THIS SYSTEM. THE EURO
HAS BEEN SHOWN VERY GOOD RUN TO RUN CONSISTENCY WITH THIS SYSTEM.
THIS WOULD CONTINUE TO SUPPORT RAIN AND TEMPS WELL INTO THE 40S FOR
THE FIRST THING ON WED MORNING WITH THE FRONT KNOCKING AT OUR
DOORSTEP. THE FRONT IS EXPECTED TO PASS THROUGH DURING THE DAY ON
WED. THIS WILL BRING SOMEWHAT COLDER AIR IN AND CHANGE RAIN SHOWERS
TO SNOW SHOWERS BY WED EVENING. A FEW SNOW SHOWERS WILL REMAIN WED
NIGHT BEFORE THE UPPER WAVE MOVES NE OF THE AREA.

WE WILL SEE A DRY AND COOL PERIOD ON THU AND THU NIGHT BEFORE MORE
PCPN WILL BECOME POSSIBLE FRI AND FRI NIGHT. RIDGING WILL MOVE
THROUGH ON THU...AND SLIP EAST OF THE AREA ON THU NIGHT. A WAVE WILL
THEN MOVE IN FROM THE EAST ON FRI AND INTRODUCE PCPN CHCS TO THE
AREA. THIS WAVE IS EXPECTED TO TAKE A TRACK JUST SOUTH OF THE STATE
LINE.

THERE IS UNCERTAINTY WITH REGARDS TO HOW STRONG THE SYSTEM
WILL BE. THE EURO PHASES A WAVE COMING IN FROM THE NW WITH THE
INITIAL WAVE AND HAS THE SYSTEM A BIT STRONGER THAN THE UNPHASED
GFS. ENOUGH WARMER AIR MAY SNEAK IN ALONG THE SOUTH FOR A MIXTURE OF
PCPN...WHILE NRN AREAS WOULD SEE MAINLY SNOW. THE EURO BEING
STRONGER AND PHASED WOULD BRING MORE PCPN AND POTENTIALLY
ACCUMULATING SNOW TO PORTIONS OF THE AREA. WHERE AND HOW MUCH IS
STILL QUITE UNCERTAIN...AND WILL NEED TO BE MONITORED.

COLDER AIR THEN LOOKS TO FILTER IN NEXT WEEKEND BEHIND THE FRI
SYSTEM WITH NW FLOW ALOFT TAKING CONTROL OF THE AREA ONCE AGAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1215 AM EDT MON MAR 17 2014

VFR CONDITIONS EXPECTED THROUGH MONDAY EVENING. EAST WINDS LESS
THAN 10 KTS TONIGHT WILL TURN SOUTHEAST MONDAY MORNING AND
INCREASE TO ABOUT 10-12 KTS.

&&

.HYDROLOGY...
ISSUED AT 325 PM EDT SUN MAR 16 2014

RIVERS FOR THE MOST PART ARE HOLDING STEADY THANKS TO THE FREEZING
TEMPERATURES. HOWEVER FROM TUESDAY INTO WEDNESDAY THE STRONG
WINDS... TEMPERATURES IN THE 40S AND DEW POINTS RISING ABOVE
FREEZING WILL FREE UP MORE WATER AND LIKELY PUSH RIVER LEVELS UP.
AT THIS POINT THE SYSTEM IS NOT STRONG ENOUGH FOR DANGEROUSLY
STRONG MELT OFF... SO LIKE THE PAST FEW SYSTEMS... ANOTHER PERIOD
OF MELTING BUT NOT ENOUGH TO CAUSE DANGEROUS FLOODING.

&&

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

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...EBW
HYDROLOGY...WDM