Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 061147
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
747 AM EDT MON JUL 6 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 AM EDT MON JUL 6 2015

TODAY WILL BE THE WARMEST DAY OF THE YEAR SO FAR WITH CONSIDERABLE
SUNSHINE. HIGHS WILL BE FROM THE MID 80S TO NEAR 90 DEGREES. AN
AREA OF SHOWERS AND THUNDERSTORMS WILL MOVE INTO SOUTHWEST LOWER
MICHIGAN LATER THIS EVENING THEN LINGER INTO THE MIDDAY HOURS OF
TUESDAY UNTIL A COLD FRONT MOVES THROUGH THE AREA ENDING THE
SHOWERS AND THUNDERSTORMS BRINGING COOLER AIR BACK TO THE AREA.
WEDNESDAY WILL SEE PARTLY CLOUDY SKIES WITH PLEASANT AFTERNOON
TEMPERATURES. A WAVE ON THE FRONT MAY BRING MORE SHOWERS AND
THUNDERSTORMS TO THE AREA LATER WEDNESDAY NIGHT INTO THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM EDT MON JUL 6 2015

THE PRIMARY ISSUE FOR THIS FORECAST IS THE THREAT FOR RAIN AND
THUNDERSTORMS TONIGHT INTO TUESDAY. A SECONDARY ISSUE IS JUST HOW
WARM IT WILL GET TODAY.

ONCE AGAIN WE HAVE A NON IDEAL SET UP FOR CONVECTION AHEAD OF AND
JUST BEHIND THE COLD FRONT THAT WILL COME THROUGH THE AREA TUESDAY
MORNING. THE PRIMARY SHORTWAVE TRACKS ACROSS SOUTHERN AND CENTRAL
CANADA WITH A 95 KNOT TO 100 KNOT JET CORE THAT CROSSES NORTH OF
LAKE SUPERIOR OVERNIGHT. THAT PUTS THE RIGHT ENTRANCE REGION LIFT
AREA OVER NORTHERN WISCONSIN AND THE NORTHERN HALF OF LOWER
MICHIGAN. IN RESPONSE TO THAT THE 40 KNOT LOW LEVEL JET CORE
DRIVES NORTH ACROSS NORTHEAST WISCONSIN INTO UPPER MICHIGAN EARLY
TONIGHT. THIS PUTS SOUTHWEST MICHIGAN IN THE TAIL OF THE LOW LEVEL
JET. THAT IS VERY NOT CONDUCIVE TO STRONG THUNDERSTORMS DUE TO THE
SPEED DIVERGANCE  IN WITH THAT SORT OF SET UP. ALSO AGAINST
STRONG STORMS IS THE TIME OF DAY (MIDDLE OF THE NIGHT). THE SPC
SREF SHOWS THIS WILL THE PROBABILITY OF THUNDERSTORMS FOCUSED OVER
WISCONSIN TONIGHT AND ONLY AS FAR EAST AS US-131 WITH ITS LOWEST
PROBABILITY IT PLOTS ON THE MAPS IN OUR CWA.

THERE IS STILL DEEP MOISTURE IN PLACE EVEN SO... THUS I DO
BELIEVE WE WILL SEE RAIN FROM THIS EVENT. THERE IS AN AREA OF
ISENTROPIC LIFT JUST BEHIND THE FRONT TUESDAY MORNING IN RESPONSE
TO THE JET ENTRANCE REGION THAT CROSSES JUST NORTH OF HERE. THAT
AREA OF LIFT IS WHAT SHOULD BRING US RAIN TUESDAY MORNING.
INSTABILITY IS ANEMIC SO STRONG STORMS SEEM NEARLY OUT OF THE
QUESTION. DEEP LAYER SHEAR IS NOT ALL THE SPECIAL EITHER. THE
EXTENSIVE CLOUD COVER WILL ASLO BE AN EVENT KILLER FOR STRONG
STORMS. AS I KEEP SAYING THOUGH...IT WILL RAIN NONE THE LESS.

SKIES WILL CLEAR TOMORROW NIGHT AS THE FRONTAL BAND MOVES EAST OF
THE AREA.  HIGH PRESSURE WILL GIVE US A PARTLY SUNNY AND COOLER
DAY WEDNESDAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM EDT MON JUL 6 2015

AS THE LONG TERM BEGINS...A COLD FRONT IS PROGD TO BE LOCATED OVER
CENTRAL IL/IN. THIS FRONT WILL BEING TO MOVE NORTH AGAIN IN RESPONSE
TO A WAVE ON THE LOW MOVING TOWARD LOWER MICHIGAN. MODELS ARE
ACTUALLY IN PRETTY GOOD AGREEMENT WITH THIS WAVE AND PAINT SOME PCPN
OVER THE SOUTHERN HALF OF THE CWA THURSDAY. FRIDAY LOOKS DRY. THEN
ANOTHER LOW IS PROGD TO DEVELOP FRIDAY. THE MODELS ARE TRYING TO
DEVELOP THIS LOW IN THE MIDDLE OF SFC HIGH PRESSURE...AND GENERATE
PCPN. CONFIDENCE ISN`T HIGH THAT THAT WILL OCCUR. IT SEEMS MORE
PLAUSIBLE THAT THE SFC BOUNDARY WILL BE JUST SOUTH OF THE CWA ALONG
WITH MOST OF THE PCPN FRIDAY. THEN AS THE HIGH MOVES EAST
SATURDAY...PCPN WILL PUSH FARTHER NORTH INTO LOWER MICHIGAN AS A
QUASI WARM FRONT.

TEMPS WILL BE WARMEST OVER THE WEEKEND WITH HIGHS IN THE 80S.
OTHERWISE...HIGHS IN THE 70S ARE EXPECTED.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 747 AM EDT MON JUL 6 2015

ANY REMAINING FOG/MIST WILL MIX OUT BY 14Z THEN I EXPECT GENERALLY
CLEAR SKIES THROUGH THE DAY (NO CLOUDS BELOW 12000 FT AGL). WINDS
WILL BECOME SOUTH WITH GUSTS TO NEAR 20 KNOTS AT TIMES THIS
AFTERNOON. THE STORMS ALONG THE COLD FRONT WILL WEAKEN AS THEY
CROSS LAKE MICHIGAN THIS EVENING. HOWEVER THERE IS ENOUGH MID
LEVEL MOISTURE THAT I DO THINK SOME LIGHT RAIN WILL REACH AT LEAST
THE WESTERN TAF SITES BY MORNING. CIGS/VSBY SHOULD BECOME MVFR BY
THEN.

&&

.MARINE...
ISSUED AT 328 AM EDT MON JUL 6 2015

I EXPANDED BOTH THE A SMALL CRAFT ADVISORY AND THE BEACH HAZARDS
STATEMENT THROUGH TUESDAY AFTERNOON.

WINDS WILL INCREASE TO 15 TO 25 KNOTS IN THE NEAR SHORE AREAS BY
AFTERNOON AHEAD OF THE COLD FRONT THEN WE WILL LIKELY SEE SOME
GUSTY NORTH WINDS BEHIND THE FRONT TUESDAY AS THE COLD AIR COMES
IN. THUS... I SEE NO REASON NOT TO CONTINUE OUR CURRENT HEADLINES
AS IS AND EXPAND THEM IN TIME THROUGH TUESDAY AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 1100 AM EDT SUN JUL 5 2015

THERE ARE NO IMMEDIATE HYDRO CONCERNS AT THIS TIME.

PERSISTENT DRY WEATHER HAS ALLOWED RIVERS TO FALL BACK WITHIN
THEIR BANKS OVER THE LAST SEVERAL DAYS. RIVERS EITHER CONTINUE TO
SLOWLY FALL OR HAVE BECOME STABLE. A ROUND OF RAINFALL IS EXPECTED
MONDAY NIGHT WITH QPF AROUND 0.50-0.75 INCHES. THE MORE ACTIVE
STORM TRACK STAYS SOUTH OF THE CWA FOR MOST OF THE WEEK BUT NUDGES
NORTHWARD BY THE END OF THE 7 DAY PERIOD. CONDITIONS MAY BECOME
WET AGAIN TOWARD THE END OF THE WEEK...PENDING THE LOCATION OF THE
BOUNDARY. RAINFALL AMOUNTS THROUGH THE WEEK...AS A WHOLE...ARE
NOT REALLY CONCERNING BUT MORE SO BENEFICIAL WITH THE RECENT DRY
PATTERN.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM 2 PM EDT THIS AFTERNOON THROUGH
     TUESDAY AFTERNOON FOR MIZ037-043-050-056-064-071.

LM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT
     TUESDAY FOR LMZ844>849.

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...04
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM


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