Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 241809
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
209 PM EDT FRI OCT 24 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT FRI OCT 24 2014

FAIRLY BENIGN WEATHER WILL CONTINUE THROUGH THE WEEKEND WITH DRY
WEATHER CURRENTLY FORECAST THROUGH SUNDAY. A COLD FRONT WILL SWEEP
THROUGH THE REGION SATURDAY MORNING...BUT IT SHOULD PASS THROUGH
DRY. HIGH TEMPERATURES FRIDAY THROUGH SUNDAY WILL BE SLIGHTLY ABOVE
NORMAL TOPPING OUT AROUND 60 DEGREES EACH DAY. NORMAL HIGHS FOR THIS
TIME OF YEAR ARE IN THE MIDDLE TO UPPER 50S. A LOW PRESSURE SYSTEM
MOVING THROUGH THE GREAT LAKES EARLY NEXT WEEK WILL BRING CHANCES
FOR SHOWERS AND THUNDERSTORMS ALONG WITH WARM AIR. HIGHS MONDAY AND
TUESDAY WILL PUSH TOWARDS 70 DEGREES...ESPECIALLY ACROSS SOUTHERN
LOWER MICHIGAN.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM EDT FRI OCT 24 2014

NO REAL CONCERNS IN THE SHORT TERM WITH DRY WEATHER FORECAST THROUGH
THE PERIOD. THE MAIN ISSUE WILL BE CLOUDS.

WIDESPREAD STRATUS AND STRATOCUMULUS LOCATED UPSTREAM WILL MOVE INTO
LOWER MICHIGAN TODAY AND SHOULD PROVIDE A MOSTLY CLOUDY DAY. THERE
IS SOME INDICATION THAT THE CLOUDS MAY BE TRYING TO EXIT THE EASTERN
CWA LATE IN THE DAY WITH CLEARING IN THE WEST...BUT THINKING WE WILL
LIKELY HANG ON TO CLOUDS MUCH OF THE DAY.

CLEARING WILL OCCUR TONIGHT FOR A TIME...BEFORE MOISTURE STREAMS
BACK IN AHEAD OF THE COLD FRONT APPROACHING FROM THE WEST. SO...IN
GENERAL A PARTLY CLOUDY NIGHT...BUT WE SHOULD TURN MOSTLY CLOUDY IN
MOST AREAS BY DAYBREAK SATURDAY.

THE FRONT ON SATURDAY STILL LOOKS TO TRAVERSE THE AREA DRY. MOISTURE
IS NOT ALL THAT IMPRESSIVE IN THE 1000-700MB LAYER AND MOST OF THE
DYNAMICS REMAIN TO THE NORTH. THE ASSOCIATED UPPER WAVE IS LOCATED
IN THE NORTHERN GREAT LAKES WITH LITTLE IF ANY VERTICAL MOTION DOWN
OUR WAY. CLOUDS SHOULD BE THE MAIN IMPACT WITH THIS SYSTEM.

THE CLOUDS WILL EXIT THE EAST SATURDAY AFTERNOON...WITH CLEARING
TAKING PLACE FROM WEST TO EAST THROUGH THE DAY. HIGH PRESSURE
SETTLES INTO THE AREA FOR SATURDAY NIGHT AND SUNDAY WITH MOSTLY
CLEAR SKIES.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 AM EDT FRI OCT 24 2014

THE MODELS HAVE TRENDED INTO VERY GOOD AGREEMENT THROUGH MUCH OF THE
LONG TERM PERIOD.  MUCH WARMER AIR ARRIVES AT THE BEGINNING OF THE
LONG TERM AS A LONG WAVE UPPER TROUGH DEVELOPS OVER THE ROCKIES.
THIS PUMPS THE WARMER AND MORE MOIST AIR INTO THE REGION.  A WARM
FRONT SHOULD COME THROUGH MONDAY MORNING.  ALL THE MODELS SHOW SOME
CONVECTION NORTH OF THE FRONT LATE SUNDAY NIGHT INTO MONDAY ALONG
AND NORTH OF I-96.  I INCREASED POPS SLIGHTLY OVER THE NORTHERN CWA
WITH THIS FRONT. BY MONDAY AFTERNOON H8 TEMPS SURGE TO +14C WHICH
SHOULD SUPPORT MAX TEMPS OF 65 TO 70 ACROSS MUCH OF THE CWA...
POSSIBLY HIGHER...DEPENDENT ON IF ANY SUN COMES THROUGH BEHIND THE
FRONT.

THE MODELS HAVE TRENDED QUICKER WITH A COLD FRONT THAT APPEARS TO
COME THROUGH TUESDAY MORNING NOW.  WE SHOULD SEE A LINE OF SHOWERS
AND A FEW THUNDERSTORMS WITH IT.  THEN...IF THE TIMING  VERIFIES WE
SHOULD SEE FALLING TEMPS TUESDAY AFTERNOON AS H8 TEMPS CRASH.  IN
FACT THE MODELS HAVE ALSO TRENDED COLDER BEHIND THIS FRONT WITH H8
TEMPS PLUNGING TO AROUND -1C BY TUESDAY NIGHT.  HAVE LOW POPS FOR
TUESDAY NIGHT...BUT IF THE COLDER TREND CONTINUES WE MAY NEED TO
INCREASE POPS AS SOME LAKE EFFECT SHOWERS COULD BE POSSIBLE THEN.

THE MID WEEK PERIOD LOOKS MAINLY DRY AND SEASONABLY COOL AS THE LONG
WAVE UPPER TROUGH EXITS AND ZONAL FLOW DEVELOPS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 210 PM EDT FRI OCT 24 2014

THE LOW CLOUDS SHOULD CLEAR OUT BY LATE AFTERNOON ONLY TO
REDEVELOP BY MIDNIGHT OR SO.

THE PRIMARY ISSUE IS WHAT HAPPENS TO THE IFR CIGS NORTH AND WEST
OF MKG (OVER EASTERN WISCONSIN...LAKE MICHIGAN... AND NORTHWEST
LOWER MICHIGAN) OVER THE NEXT FEW HOURS. LOOKING AT THE VISIBLE
SATELLITE LOOPS IT SEEMS THE CLEARING IS WORKING NORTHWARD OVER
THE PAST FEW HOURS. THAT TREND GOES ALONG WITH BOTH THE RAP AND NAM
950 TO 850 MB RH FORECAST WHICH ALSO SHOWS CLEARING OF LOW CLOUDS.
BY LATE AFTERNOON MOST LOCATIONS. SO THAT IS WHAT I DID WITH THE
TAF FORECAST FOR THIS AFTERNOON.

THE NEXT ISSUE IS FOG/STRATUS TONIGHT. THE NAMDNG5...WHICH I HAVE
NOTED DOES VERY NICELY WITH FORECASTING FOG AND FOR THAT MATTER
SO DOES THE RAP13...BOTH SHOW NEARLY THE ENTIRE CWA GOING DOWN IN
FOG BY 09Z. THE PROBLEM THERE THOUGH IS THERE IS 15 TO 20 KNOTS OF
WIND IN THE BOUNDARY LAYER. THAT WOULD SUGGEST TO ME A STRATUS
DECK IS MORE LIKELY. SO MY TAFS SHOW CLEARING BY LATE AFTERNOON
THEN I BRING THE FOG AND LOW CLOUDS BACK LATE TONIGHT. FOR THE MOST
PART THE LOW CLOUDS WILL BE SLOW TO MIX OUT SATURDAY.

&&

.MARINE...
ISSUED AT 330 AM EDT FRI OCT 24 2014

LIGHT SOUTHERLY FLOW TODAY WILL KEEP WAVE HEIGHTS IN CHECK. SOUTH
WINDS BEGIN TO INCREASE TONIGHT AHEAD OF A COLD FRONT BUT SHOULD
STAY JUST BELOW SMALL CRAFT ADVISORY CRITERIA. THE NEXT TIME FRAME
OF CONCERN WILL BE SATURDAY BEHIND A COLD FRONT WHERE WEST AND
NORTHWEST WINDS WILL LIKELY RAMP INTO THE 15 TO 25 KNOT RANGE. WAVES
SHOULD BUILD INTO THE 3 TO 6 FOOT RANGE. AT THIS POINT WILL HOLD OFF
ON A PERIOD 3 SMALL CRAFT ADVISORY. ONE WILL LIKELY BE NEED THOUGH.


&&

.HYDROLOGY...
ISSUED AT 330 AM EDT FRI OCT 24 2014

HYDRO CONCERNS ARE LIMITED THROUGH THIS WEEKEND WITH LOW RIVER
LEVELS AND NO PRECIPITATION FORECAST. THE NEXT CHANCE FOR SOLID RAIN
COMES SUNDAY NIGHT INTO EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM
TRAVERSES THE AREA. PWAT VALUES INCREASE TO AROUND 1.25 INCHES WHICH
IS ABOVE THE 75 PERCENTILE FOR THIS TIME OF YEAR. THE AMOUNT OF RAIN
EXPECTED THOUGH SHOULD BE ABLE TO BE ABSORBED WITHOUT ISSUE GIVEN
LOW FLOWS.

&&

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

$$

SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...JK
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE






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