Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 080430
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1230 AM EDT TUE JUL 8 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 342 PM EDT MON JUL 7 2014

ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE TONIGHT
AND TUESDAY MORNING AS THE NEXT FRONTAL BOUNDARY DROPS DOWN FROM THE
NORTHWEST. THIS WILL BE FOLLOWED BY COOLER WEATHER FOR THE MID TO
LATE WEEK PERIOD WITH A FEW SCATTERED RAIN SHOWERS STILL POSSIBLE
TUESDAY NIGHT AND WEDNESDAY.

&&

.UPDATE...
ISSUED AT 947 PM EDT MON JUL 7 2014

NO MAJOR CHANGES TO THE FCST FOR TONIGHT. WE HAVE BUMPED UP
THE CHCS OF SHOWERS/STORMS ACROSS THE SW PORTION OF THE CWFA FOR
LATE TONIGHT AS PCPN LOOKS TO COME IN A TAD EARLIER. LATEST MODEL TRENDS
CONTINUE TO HAVE THE SHORT WAVE NOW COMING INTO MN DIVING SE
TOWARD THE AREA LATE TONIGHT. AS IT DIVES IN...IT WILL BRING UP A
SHORT WAVE FROM THE SW...AND HELP TO EXPAND PCPN INTO THE AREA
LATE TONIGHT AND TUE MORNING. WE SEE A SURGE OF THE WARM SECTOR
SOUTH OF THE AREA INTO THE SRN PORTION OF THE CWFA WHERE 1500 J/KG
OF ML CAPE WILL BE POSSIBLE LATE TONIGHT/EARLY TUE. DEEP LAYER
SHEAR IS STILL EXPECTED TO BE ON THE ORDER OF 30-40 KNOTS WHICH
WILL BRING THE POTENTIAL OF STORM ORGANIZATION SOUTH. BOTH WIND
AND HAIL WILL BE POTENTIAL THREATS DOWN SOUTH.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 342 PM EDT MON JUL 7 2014

SHORTWAVE CURRENTLY OVER THE NRN PLAINS REGION WILL HEAD SOUTHEAST
TONIGHT AND BRING MORE SHOWERS AND STORMS. CURRENT MODEL GUIDANCE
SUGGESTS THE POSSIBILITY OF SPLIT PRECIPITATION CENTERS RELATED TO
TO TWO SEPARATE VORTICITY MAXIMA... WITH ONE BATCH IMPACTING NRN WI
AND NRN LWR MI AND ANOTHER DEVELOPING OVER NRN MISSOURI THEN
SPREADING/EXPANDING NORTHEAST TOWARD SE LWR MI AND NW OHIO.

DESPITE LESS THAN OPTIMAL TIMING OF THIS NEXT SHORTWAVE FOR SEVERE
WEATHER... MODELS STILL SHOW 1000-2000 J/KG OF SFC BASED CAPE
DEVELOPING 06Z-12Z TUESDAY AS HIGHER SFC DEW POINTS SPREAD BACK IN
FROM THE SOUTHWEST LATE TONIGHT AND EARLY TUESDAY MORNING AHEAD OF
THE APPROACHING WAVE. THE MAIN AREA OF CONCERN WHERE SEVERE WEATHER
CANNOT BE RULED OUT LATE TONIGHT AND EARLY TUESDAY IS SOUTH AND EAST
OF GRR WHERE THIS INSTABILITY IS PROGGED. 0-6KM DEEP LAYER SHEAR OF
35 TO 40 KNOTS IS PROGGED WHICH WOULD SUPPORT ORGANIZED STORMS.

PASSAGE OF THE SHORTWAVE AND SFC FRONT SHOULD LEAD TO PREDOMINATELY
DRY WEATHER FOR TUESDAY AFTERNOON. HOWEVER AS THE UPPER TROUGH DIGS
OVER THE GREAT LAKES THERE WILL BE ADDITIONAL SPOKES OF VORTICITY
PIVOTING/ROTATING THROUGH THE REGION THAT MAY SUPPORT MORE WIDELY
SCATTERED SHOWERS AND STORMS TUESDAY NIGHT AND WEDNESDAY.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 342 PM EDT MON JUL 7 2014

HIGH PRESSURE AND NORTHWEST UPPER FLOW WILL KEEP THE REGION COOL AND
DRY THURSDAY INTO MOST OF FRIDAY.  WARMER AIR...WITH NEAR NORMAL
TEMPS ARRIVES FRIDAY NIGHT...AND PERSISTS THROUGH MONDAY.

THE NEXT CHANCE FOR SHOWERS AND STORMS SHOULD COME FRIDAY EVENING
AND MAY LINGER THROUGH MUCH OF THE WEEKEND. THE MODELS CONTINUE TO
STRUGGLE WITH HOW QUICKLY THE UPPER RIDGE FLATTENS AND HOW SOON A
SHORT WAVE COMES THROUGH.  THE EURO PUSHES THIS THROUGH BY
SATURDAY...BUT THE GFS BRINGS THE MAIN WAVE THROUGH HERE SATURDAY
NIGHT.  THE GFS HAS HAD DECENT CONSISTENCY SO SIDED SOMEWHAT WITH
IT...BUT CONFIDENCE IS LOWER THAN NORMAL FOR THE SECOND HALF OF THE
WEEKEND.

IT APPEARS SUNDAY NIGHT AND MONDAY SHOULD BE DRY WITH ZONAL FLOW AND
SURFACE RIDGING MOVING IN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1230 AM EDT TUE JUL 8 2014

AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL MOVE THROUGH
THE TAF SITES BETWEEN 07Z AND 15Z OR SO. THEY WILL AFFECT KMKG
FIRST AND EXIT EAST OF KLAN AND KJXN AROUND 15Z-16Z. THE SHOWERS
AND STORMS WILL LIKELY HAVE VFR BASES FOR THE MOST PART THAT MAY
DIP LOWER BRIEFLY IN THE HEAVIER SHOWERS. MVFR VISIBILITIES LOOK
LIKELY AS THE PRECIPITATION ROLLS THROUGH.

THERE IS SOME INDICATION THAT THERE MAY BE A BIT OF FOG/STRATUS
AROUND THEN IN THE WAKE OF THE SHOWERS BETWEEN 10Z-14Z...BUT DID
NOT INCLUDE THIS IN THE TAFS AS IT IS LOW CONFIDENCE.

CONDITIONS SHOULD BE VFR AHEAD OF THE SHOWERS/STORMS OVERNIGHT AND
THEN AGAIN IN THE WAKE OF THE ACTIVITY TUESDAY AFTERNOON/EVENING.

THE WINDS WILL PICK UP TUESDAY MIDDAY AND AFTERNOON OUT OF THE
WEST...BECOMING GUSTY IN THE 15-25 KNOT RANGE. WINDS WILL TAPER
BACK AFTER 00Z TOMORROW EVENING.

&&

.MARINE...
ISSUED AT 342 PM EDT MON JUL 7 2014

AT THIS POINT IT APPEARS THAT WINDS AND WAVES WILL STAY MOSTLY BELOW
SMALL CRAFT ADVISORY CRITERIA. HOWEVER WE WILL HAVE TO MONITOR THE
POTENTIAL STRENGTH OF THE WESTERLY FLOW BEHIND THE FRONT TUESDAY
AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 1220 PM EDT MON JUL 7 2014

EXCESSIVE RAINFALL OVERNIGHT IN THE HARDEST HIT AREAS RANGED FROM
2 TO 6 INCHES. THIS HAS LED TO ROAD WASHOUTS AND CLOSURES WITH A
FEW RISING RIVERS AND STREAMS. TRAVEL MAY CONTINUE TO BE IMPACTED
THROUGH EARLY MONDAY EVENING ACROSS IONIA...MONTCALM...AND GRATIOT
COUNTIES WHERE THERE IS STANDING WATER. ADDITIONAL RAINFALL
OVERNIGHT IS NOT EXPECTED TO AMOUNT TO MORE THAN A HALF INCH OR SO
ON AVERAGE. LOCALIZED HIGHER AMOUNTS ARE POSSIBLE BUT OVERALL WE
ARE NOT EXPECTING SIGNIFICANT HYDROLOGIC ISSUES OVERNIGHT AND INTO
TUESDAY.

AS FOR THE RIVERS AND STREAMS...OUR MAIN CONCERN RESIDES WITH THE
PINE RIVER AT ALMA (JUST UNDER 5" OF RECORDED RAIN THERE). A RIVER
FLOOD WARNING IS IN EFFECT FOR MINOR FLOODING THROUGH LATE TUESDAY
NIGHT. RISES ON THE GRAND ARE EXPECTED WITH BANKFULL BEING
EXCEEDED AT IONIA. RISES ON THE MAPLE RIVER WILL ALSO SEND THE
RIVER ABOVE BANKFULL AT MAPLE RAPIDS. WE`LL ALSO NEED TO MONITOR
THE LOOKING GLASS RIVER AT EAGLE FOR READINGS NEAR BANKFULL. HIGH
LEVELS WILL CONTINUE ON THESE RIVERS FOR THE NEXT FEW DAYS.

&&

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

$$

UPDATE...NJJ
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...JK
AVIATION...DUKE
HYDROLOGY...HOVING
MARINE...MEADE






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