718
FXUS63 KAPX 272015
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
315 PM EST THU FEB 27 2020
NEAR TERM
(THROUGH FRIDAY)
ISSUED AT 312 PM EST THU FEB 27 2020
..A MAJOR SNOW BAND
HIGH IMPACT WEATHER POTENTIAL...MODERATE TO HEAVY SNOW BANDS WILL
CONTINUE OVER THE REGION FOR MAINLY NW LOWER AND E UPPER MICHIGAN.
PATTERN SYNOPSIS/FORECAST...SFC LOW NORTH OF NEW YORK IS PINWHEELING
A SFC TROUGH THROUGH THE GREAT LAKES. THIS IS BEGINNING TO SHIFT THE
WINDS OVER THE UPPER GREAT LAKES. THIS SHIFT IS VEERING THE WINDS TO
THE N AND IS BEGINNING TO CAUSE SOME BAND CONVERGENCE OVER N LAKE
MICHIGAN AND NW LOWER. THIS WILL CONTINUE INTO EVENING PUSHING THE
ONGOING SNOW BANDS INTO THE SW PORTION OF THE FORECAST AREA. THE
SNOW BANDS THIS AFTERNOON ARE SEEING A BIT OF THE DIURNAL DISRUPTION
FROM THE SUNSHINE FOR THE EARLY SPRING, AS WE TYPICALLY DO. HOWEVER,
NOT TO THE EXTENT AS USUAL, AS THE WINDS ARE STRONG ENOUGH TO
OVERCOME THE OVERLAND CAPE. AS THE SUNSETS, THE DIURNAL DISRUPTION
WILL END, AND BANDS WILL BECOME MORE DISCREET, AND WITH THE SFC
TROUGH ROTATING SOUTH, THE WINDS WILL BEGIN TO GO BACK TO THE NW
AROUND 03Z/FRI, AND THEN ANOTHER TROUGH IS EXPECTED TO PINWHEEL
AROUND, AND PUSH THE WINDS N AGAIN(AND THE BANDS WILL TREND SOUTH).
FOR THE DAY ON FRIDAY, THE WINDS WILL REMAIN MORE NNW, AS THE DRIER
AIR BEGINS TO MOVE INTO THE REGION AND THE BANDS BEGIN TO DIMINISH
BY THE AFTERNOON.
PRIMARY FORECAST CONCERNS...MAIN CONCERN IS SNOW AMOUNTS. THE
PROBLEM WILL BE RESIDENCE TIME OVER THE AREA, AND BAND CONVERGENCE.
AS WITH MOST LAKE EFFECT THIS WILL BE A MONITOR AND FIND THE AMOUNT
OF SNOW, TO UPDATE. AMOUNTS MAY BE A BIT UNDER DONE IF THE SNOW BAND
SITS IN ONE PLACE TOO LONG. MOST OF THE BANDS WILL BE MODERATE
AMOUNTS OF SNOW (3-5") BUT THE BIGGEST BAND IF IT SITS WILL BE HEAVY
(6+"). AND THE PLUS SIDE COULD BE MUCH MORE SIGNIFICANT (12+"?)
SHORT TERM
(FRIDAY NIGHT THROUGH SUNDAY)
ISSUED AT 312 PM EST THU FEB 27 2020
HIGH IMPACT WEATHER POTENTIAL: SOME POSSIBLE MINOR LAKE EFFECT
SNOW ACCUMULATIONS FRIDAY NIGHT.
BEHIND A DEPARTING LOW PRESSURE SYSTEM, THE WINDS WILL CONTINUE TO
BE NORTHWESTERLY WITH COLDER AIR CONTINUING TO FILTER IN (-18 TO -
20C 850MB TEMPERATURES)...WHICH WILL CONTINUE TO PRODUCE SOME
LAKE EFFECT SNOW FOR PORTIONS OF NORTHWEST LOWER AND
EASTERN UPPER MICHIGAN THROUGH FRIDAY NIGHT AND INTO THE EARLY
PARTS OF SATURDAY MORNING. ACCUMULATIONS SHOULD BE MINOR THROUGHOUT
THIS PERIOD. ALTHOUGH THE PATTERN APPEARS TO REMAIN PROGRESSIVE, THE
NORTHWESTERLY FLOW BECOMES ANTI-CYCLONIC AHEAD OF AN AMPLIFIED RIDGE
OF HIGH PRESSURE AND MUCH DRIER AIR...WHICH SHOULD DIMINISH ANY
LINGERING LAKE EFFECT SNOW BY SATURDAY MORNING. WINDS WILL BEGIN TO
BACK TO WESTERLY AND DIMINISH IN INTENSITY SATURDAY AFTERNOON AND
CONTINUE TO BACK TO SOUTHERLY WINDS BY SUNDAY MORNING AHEAD OF A
WEAK COLD FRONT ASSOCIATED WITH A CLIPPER SYSTEM OVER WESTERN
ONTARIO. THIS CLIPPER SYSTEM WILL PRODUCE SOME SNOW SHOWERS AND
POSSIBLY MIXED WITH RAIN AT TIMES AS THE SOUTHERLY WINDS ADVECT
WARMER TEMPERATURES TO THE FORECAST AREA. MOST PRECIPITATION APPEARS
TO BE CONFINED TO NORTHERN LOWER AT THIS TIME. HIGH TEMPERATURES
WILL BE IN THE UPPER 20S TO LOW 30S SATURDAY AND MODERATE INTO THE
UPPER 30S TO LOW 40S BY SUNDAY AND GET EVEN WARMER MONDAY WITH THE
SOUTHERLY WIND FLOW WITH PORTIONS OF NORTHEAST LOWER POSSIBLY
REACHING INTO THE MID TO UPPER 40S.
LONG TERM
(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 312 PM EST THU FEB 27 2020
HIGH IMPACT WEATHER POTENTIAL: MINIMAL.
HIGH PRESSURE APPEARS TO DOMINATE THE FORECAST AREA THROUGH AT LEAST
TUESDAY AFTERNOON...PRODUCING PRECIPITATION-FREE WEATHER AND MOSTLY
CLEAR SKIES TO PARTLY CLOUDY SKIES. THE NEXT CHANCE FOR
PRECIPITATION WILL BE LATE TUESDAY/EARLY WEDNESDAY WITH A CLIPPER
SYSTEM TO OUR NORTH AND A DEVELOPING LOW IN THE SOUTHERN PLAINS
TREKKING TOWARDS THE GREAT LAKES REGION...ALTHOUGH MODELS HAVE NOT
BEEN VERY CONSISTENT NOR IN AGREEMENT ON SAID SYSTEMS. WILL HAVE TO
KEEP AN EYE ON THESE SYSTEMS AND CONTINUE TO UPDATE THE FORECAST AS
NECESSARY. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO MID 40S
TUESDAY AND WEDNESDAY, WHILE COOLING A BIT THURSDAY...REACHING INTO
THE LOW TO MID 30S.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 129 PM EST THU FEB 27 2020
LAKE EFFECT SNOW BANDS ARE AFFECTING THE REGION, ESPECIALLY NW
LOWER MICHIGAN (PLN/TVC/MBL), WITH SOME AFFECT AT APN. SO FAR, THE
MAIN SNOW BAND HAS BEEN JUST NORTH OF TVC AFFECTING AREAS AROUND
ACB. SMALLER SNOW BANDS NEAR TVC AND MBL HAVE BEEN KEEPING THE
SNOW LIGHT FOR THE MOST PART. PLN HAS SEEN A FEW BANDS RECENTLY
DROPPING THE VSBY NEAR IFR CATEGORIES.
WINDS ARE EXPECTED TO TURN MORE TO THE NNW OVER THE NEXT FEW
HOURS, AND PUSH THE SNOW INTO TVC AND MAYBE MBL AND CONTINUE INTO
THE EVENING, AFTER THAT THE WINDS ARE EXPECTED TO BACK TO THE NW
AGAIN AND PUSH THE BANDS BACK NORTH OF TVC AND MBL AGAIN, UNTIL
AFTER 09Z/FRI WHEN THE WINDS VEER TO THE N AGAIN AND PUSH THE
BANDS BACK INTO THE TVC AND MBL.
AS THE WINDS CHANGE AT PLN, THE OPPOSITE WILL HAPPEN. AS THE WINDS
BECOME MORE NORTH, PLN VSBY WILL IMPROVE INTO THE EVENING, BEFORE
BACKING TO THE NW ALLOWING BANDS BACK INTO THE TAF SITE. AND THEN
THE WIND GO BACK TO NORTH AROUND 09Z/FRI AND THE VSBY WILL IMPROVE
AGAIN.
APN CURRENTLY, HAS VFR TO MVFR CIGS AND VFR VSBYS, AND THE SNOW
BANDS HAVE NOT BEEN ABLE TO REACH ACROSS N LOWER MI. HOWEVER, LAKE
BANDS ON LAKE HURON MAY GET PUSHED INTO APN AS THE WINDS BEGIN TO
SHIFT TO THE NNW. HOWEVER, NO PROLONGED LAKE EFFECT SNOW IS
EXPECTED AS THE BANDS WILL TRANSIT THE REGION AS THE WINDS SWING
BACK AND FORTH.
MARINE
ISSUED AT 312 PM EST THU FEB 27 2020
TONIGHT THROUGH SATURDAY...GALES CONTINUE OVER LAKE MICHIGAN AND
LAKE HURON INTO THE FRIDAY MORNING AS THE SFC LOW NEAR NEW YORK,
CONTINUES WITH THE TIGHT GRADIENT. THE LOW WILL BEGIN TO MOVE TO THE
EAST BY FRIDAY MORNING AND THE GRADIENT WILL SLACKEN, DIMINISHING
THE WIND ON LAKE MICHIGAN FRIDAY NIGHT AND BY SATURDAY MORNING ON
LAKE HURON. WINDS OVER THE UPPER GREAT LAKES LOOK TO BE VARIABLE
UNDER 10 KNOTS FOR THE WEEKEND.
APX WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST FRIDAY FOR MIZ086>088.
WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MIZ020-022-026-
028-033-099.
LAKESHORE FLOOD ADVISORY UNTIL 11 AM EST FRIDAY FOR MIZ016-018-
020-021-025-031-099.
WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ021-027.
LH...GALE WARNING UNTIL 6 AM EST FRIDAY FOR LHZ346-349.
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LHZ347-348.
SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LHZ345.
LM...GALE WARNING UNTIL 11 AM EST FRIDAY FOR LMZ323-342-344>346.
SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ341.
LS...NONE.
NEAR TERM...JL
SHORT TERM...TL
LONG TERM...TL
AVIATION...JL
MARINE...JL
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