Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRR 261754
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
154 PM EDT SUN OCT 26 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT SUN OCT 26 2014

A WARM FRONT MOVING NORTH THROUGH MICHIGAN LATE TONIGHT AND EARLY
MONDAY WILL TRIGGER A FEW SCATTERED SHOWERS AND THUNDERSTORMS...
MAINLY NORTH OF INTERSTATE 96. MONDAY WILL BE UNSEASONABLY WARM WITH
HIGH TEMPERATURES 10 TO 20 DEGREES ABOVE NORMAL.

A COLD FRONT SWEEPING IN FROM THE WEST LATE MONDAY NIGHT AND EARLY
TUESDAY WILL BRING A PERIOD OF SHOWERS AND THUNDERSTORMS FOLLOWED BY
A RETURN TO MORE NORMAL TEMPERATURES FOR THIS TIME OF YEAR. A VERY
CHILLY AIR MASS IS EXPECTED TO ARRIVE ON HALLOWEEN WITH A CHANCE OF
MIXED RAIN AND SNOW SHOWERS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EDT SUN OCT 26 2014

OVERALL THIS DOES NOT LOOK LIKE A SIGNIFICANT CONVECTIVE EVENT FOR
SOUTHWEST MICHIGAN. MOST OF THE FORCING WITH THE WARM FRONT LATE
TONIGHT AND EARLY MONDAY IS FOCUSED TO OUR NORTH AND THE LATE NIGHT
ARRIVAL OF THE COLD FRONT MONDAY NIGHT DOES NOT REALLY FAVOR ROBUST
CONVECTION. THE OTHER POTENTIAL NEGATIVE FACTOR WITH THIS SYSTEM IS
THE CURRENT LACK OF MOISTURE AS NOTED BY CLOUD FREE SKIES AT THIS
HOUR COVERING A LARGE PART OF THE CONUS. THIS MAY LIMIT THE COVERAGE
OF SHOWERS AND THUNDERSTORMS.

DESPITE DEEP LAYER SHEAR IN EXCESS OF 30 KTS... STRONG TO SEVERE
STORMS ARE UNLIKELY SINCE THE CONVECTION WILL BE MOSTLY ROOTED ABOVE
THE BOUNDARY LAYER WITH LITTLE TO NO SFC INSTABILITY PROGGED. H8-H5
THETA E LAPSE RATES ARE PROGGED TO BE NEGATIVE AND THIS DOES
SUPPORT THE RISK OF ELEVATED STORMS WITH PERHAPS SOME SMALL HAIL.
SHOWERS AND STORMS SHOULD END BY NOON TUESDAY AS THE MID LEVEL DRY
SLOT ARRIVES RAPIDLY FROM THE SOUTHWEST BEHIND THE EXITING COLD
FRONT.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN OCT 26 2014

THE COLDER AIR SHOULD CONTINUE TO POUR INTO SW MI TO START THE LONG
TERM PERIOD.  H8 TEMPS OF -2C TO -3C SUPPORT AT LEAST SOME WEAK LAKE
EFFECT WITH INVERSION HEIGHTS AROUND 5K FT.  I BUMPED POPS UP A BIT
TUESDAY NIGHT AS THE FLOW SHOULD BE WESTERLY...CARRYING THE RAIN
SHOWERS INLAND.  ANY LAKE EFFECT SHOULD WIND DOWN ON WED AS
ANTICYCLONIC FLOW DEVELOPS.

ANOTHER SHORT WAVE IS PROGGED OVER THE REGION BY THURSDAY NIGHT.  IT
IS THIS WAVE THAT DROPS OUT OF CENTRAL CANADA THAT SHOULD GIVE US A
BRIEF SHOT OF WINTRY WEATHER.  THE SYNOPTIC WAVE SHOULD GIVE US
ANOTHER CHANCE FOR RAIN SHOWERS THURSDAY AFTERNOON INTO THURSDAY
NIGHT.  THEN THE THERMAL TROUGH WILL BE OVER THE AREA FOR FRIDAY AND
HALLOWEEN NIGHT.  THIS SHOULD SPARK MORE LAKE EFFECT WHICH SHOULD
MIX OR CHANGE TO SNOW AT TIMES... MAINLY ALONG AND NORTH OF I-96.
THERE SHOULD ALSO BE A DECENT AMOUNT OF WIND...WHICH COULD BRING
WINDS CHILLS AS LOW AS THE LOWER 20S FOR TRICK OR TREAT NIGHT.  THE
FLOW BECOMES MORE NORTHERLY INTO FRIDAY NIGHT...SO MOST OF THE LAKE
EFFECT BY THEN SHOULD BE HUGGING THE COAST.  HIGH PRESSURE APPEARS
TO BUILD IN BY SATURDAY GIVING SW MI DRY WEATHER AS THE COLDEST OF
THE AIR BEGINS TO MOVE OUT OF THE REGION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 154 PM EDT SUN OCT 26 2014

AT THIS POINT I HAVE DECIDED TO GO WITH SOLID VFR THROUGH 18Z
MONDAY FOR ALL OF OUR TAF SITES. THE MAIN ISSUE IS THE POTENTIAL
FOR SHOWERS FROM MID CLOUDS IN THE 09Z-15Z TIME FRAME AS THE MID
LEVEL WARM FRONT PUSHES THROUGH THE AREA. CURRENTLY THROUGH THE
CONDENSATION PRESSURE DEFICITS BETWEEN 700 AND 800 MB NEAR GET MUCH
LOWER THAN 15 MB AND MOSTLY ARE GREATER THAN 20 MB. THIS TELLS ME
WHAT WILL BE THERE WILL BE LIMITED AT BEST. SO I KEPT THE VCSH AT
MKG BUT ALL OTHER SITES I BROUGHT IN SOME HIGH BASED STRATOCUMULUS
CLOUDS LATE TONIGHT AND CALLED THAT GOOD.

DURING THE DAY TIME MONDAY... A DECENT WARM SURGE BUT WITH THE
WARM FRONT TO OUR NORTH AND COLD FRONT WELL WEST YET...PLUS A
GENERAL LACK OF HIGH RH VALUES AT ANY LEVEL... I BROKE THE CLOUDS
OUT TO SCATTERED MID AND HIGH CLOUDS. ANY SHOWERS WOULD BE AFTER
06Z ON TUESDAY.

&&

.MARINE...
ISSUED AT 330 AM EDT SUN OCT 26 2014

SMALL CRAFT ADVISORIES CONTINUE BUT WINDS WILL BE DECREASING TODAY
WITH THE ARRIVAL OF THE SFC RIDGE. WE MAY BE ABLE TO CANCEL THE
CURRENT HEADLINE A BIT EARLY. SMALL CRAFT ADVISORIES WILL LIKELY BE
NEEDED AGAIN ON TUESDAY IN THE WESTERLY FLOW COLD ADVECTION BEHIND
THE COLD FRONT.


&&

.HYDROLOGY...
ISSUED AT 1136 AM EDT SUN OCT 26 2014

A FEW CHANCES FOR RAIN EXIST OVER THE NEXT SEVERAL DAYS. THE KEY
NOTE HERE IS THAT THERE IS NOT MUCH IN THE WAY OF SUPPORT FOR ANY
LARGE IMPACT EVENTS. EACH EPISODE BRINGS THE POTENTIAL FOR AROUND
ONE-QUARTER OF AN INCH OR SO OF MOISTURE. THIS WOULD LIKELY BE HIGHER
IN ANY CONVECTIVE SITUATIONS. THOSE CHANCES EXIST MAINLY LATE TONIGHT
INTO MONDAY MORNING AND AGAIN EARLY TUESDAY. HOWEVER...POTENTIAL
FOR CONVECTION IS RATHER LIMITED. GENERAL RAINFALL AMOUNTS THROUGH
THE NEXT 7 DAYS LOOK TO BE ON THE ORDER OF ONE-HALF AN INCH TO ONE
INCH. IN ADDITION...MANY AREAS HAVE ONLY RECEIVED AROUND ONE-TENTH
OF AN INCH OR LESS SINCE THE 15TH OF OCTOBER. AREA RIVERS WILL
LIKELY NOT BE OF ANY CONCERN.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
     LMZ844>849.

&&

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...JK
AVIATION...WDM
HYDROLOGY...JAM
MARINE...MEADE






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.