000
FXUS63 KGRR 192345
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
745 PM EDT SUN MAY 19 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 305 PM EDT SUN MAY 19 2013

THUNDERSTORMS ARE EXPECTED TO IMPACT SOUTHERN LOWER MICHIGAN
MONDAY THROUGH WEDNESDAY....WITH SOME SEVERE WEATHER POSSIBLE EACH
DAY. COOLER AIR WILL RETURN LATE IN THE WEEK WITH LOW TEMPERATURES
POTENTIALLY IN THE UPPER 30S FOR SOME OF THE HOLIDAY WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 305 PM EDT SUN MAY 19 2013

SHORT TERM SEVERE WEATHER POTENTIAL REMAINS FOR MONDAY AFTERNOON
THROUGH TUESDAY NIGHT. LOCALIZED FLOODING MAY BE POSSIBLE IF
SEVERAL ROUNDS OR CONTINUOUS HEAVIER RAINFALL MOVES OVER THE SAME
LOCATIONS IN SHORT SUCCESSION.

STORMS RIGHT NOW LOOK LIKE THEY WILL DEVELOP BY EARLY TO MID MONDAY
AFTERNOON NEAR THE LAKE SHORE AND MOVE EAST/NORTHEAST INTO THE
EVENING. ADDITIONAL WAVES OF STORMS WILL BE POSSIBLE EARLY IN THE
EVENING AS THE BROAD SYSTEM CONTINUES TO EJECT ENERGY INTO LOWER
MICHIGAN FROM THE SOUTHWEST. SOME SEVERE STORMS WILL BE POSSIBLE
WITH POTENTIAL FOR DAMAGING WINDS AND HAIL. NOT OUT OF THE
QUESTION A QUICK TORNADO COULD SPIN UP...BUT TORNADOES DO NOT
APPEAR TO BE MUCH OF A THREAT AT THIS TIME.

UNCERTAINTIES THAT REMAIN IN THE FORECAST CENTER AROUND IF ANY
DEBRIS CLOUDS FROM ONGOING STORMS TO OUR SOUTHWEST WILL LIMIT
WARMING AND INSTABILITY MONDAY. ALSO IN PLAY IS THE LOCATION OF A
STALLING WARM FRONT THAT PUSHES NORTH THROUGH LOWER MICHIGAN THIS
EVENING/EARLY MONDAY. SEVERAL OF THE SHORT RANGE MODELS ARE INDICATING
THIS FRONT STALLING ACROSS NORTHERN LOWER AND KEEPING BEST FORCING
NORTH FOR MONDAY AFTERNOON INTO EARLY EVENING. SHOULD THESE TWO
THINGS OCCUR...ESPECIALLY THE CLOUD COVER...SOUTHWEST LOWER MICHIGAN
COULD MISS OUT ON MOST OF THE SEVERE WEATHER MONDAY AFTERNOON.

LATE MONDAY NIGHT INTO TUESDAY EVENING SEES SEVERAL MORE CHANCES OF
POTENTIAL THUNDERSTORMS WITH SLIGHTLY BETTER JET DYNAMICS WORKING
INTO LOWER MICHIGAN AND SEVERAL SHORTWAVES FROM THE UPPER SYSTEM
EJECTING TOWARD THE REGION. UNCERTAINTIES REMAIN HERE AS WELL...BUT
SEVERE POTENTIAL REMAINS...ESPECIALLY FOR TUESDAY AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 305 PM EDT SUN MAY 19 2013

WEDNESDAY LOOKS LIKE THE MOST ACTIVE DAY OF THE PERIOD. LOW PRESSURE
MOVING ACROSS THE SRN CWA WILL RESULT IN SHOWERS AND PERHAPS STORMS
WEDNESDAY AND WEDNESDAY EVENING. THE MOST LIKELY LOCATION FOR STORMS
WILL BE SOUTH OF I-96. NOT LOOKING FOR SEVERE STORMS AS INSTABILITY
WILL BE DECREASING. THE UPPER TROUGH FOLLOWING THE SFC LOW MAY
PRODUCE SOME SHOWERS THROUGH THURSDAY.

AS MEMORIAL DAY WEEKEND APPROACHES...HIGH PRESSURE OVER THE NRN
GREAT LAKES WILL PRODUCE A COOL AND DRY AIR FLOW FROM CANADA
RESULTING IN SUNNY DAYS FRIDAY/SATURDAY WITH HIGHS IN THE 60S. FROST
MAY BE A POSSIBILITY FRIDAY NIGHT ACROSS THE NRN TWO ROWS OF
COUNTIES WITH LIGHT WINDS AND CLEAR SKIES AS TEMPS FALL INTO THE MID
TO UPPER 30S.

THE HIGH WILL DRIFT EAST SUNDAY AND A WARM FRONT APPROACHING FROM
THE WEST MAY PRODUCE SOME SHOWERS AND PERHAPS STORMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 745 PM EDT SUN MAY 19 2013

EXPECT VFR CONDITIONS THROUGH MUCH OF THE NIGHT. THERE IS STILL A
CHANCE OF SOME SHOWERS WITH MVFR CONDITIONS AFTER MIDNIGHT...BUT
THIS MAY BE IN THE FORM OF DISSIPATING SHOWERS AND SO COVERAGE MAY
BE SPARSE UNTIL MORE MOISTURE ARRIVES LATER ON MONDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 305 PM EDT SUN MAY 19 2013

THUNDERSTORMS TO POSE HAZARD TO MARINERS MONDAY THROUGH
WEDNESDAY. FOG IS ALSO EXPECTED TO BE A HAZARD EACH NIGHT FROM
TONIGHT THROUGH TUESDAY NIGHT.


&&

.FIRE WEATHER...
ISSUED AT 305 PM EDT SUN MAY 19 2013

WARM AND SLIGHTLY MORE HUMID WEATHER WILL CONTINUE THROUGH THE
WEEK. THUNDERSTORMS WILL BRING LIGHTNING AND GUSTY WINDS AT TIMES
MONDAY THROUGH WEDNESDAY AFTERNOON.

&&

.HYDROLOGY...
ISSUED AT 305 PM EDT SUN MAY 19 2013

LOCALIZED FLOODING COULD OCCUR IF SEVERAL ROUNDS OF RAIN AND
THUNDERSTORMS MONDAY THROUGH WEDNESDAY OCCUR IN THE SAME LOCATION
IN SHORT SUCCESSION. OTHERWISE...NO LARGE SCALE FLOODING ISSUES
ARE EXPECTED AT THIS TIME.

&&

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

$$

SYNOPSIS...MACZKO
SHORT TERM...MACZKO
LONG TERM...93
AVIATION...OSTUNO
FIRE WEATHER...MACZKO
HYDROLOGY...LAURENS
MARINE...MACZKO