Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 252345
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
745 PM EDT TUE AUG 25 2015

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 347 PM EDT TUE AUG 25 2015

HIGH IMPACT WEATHER: NONE.
FORECAST CHALLENGE: THE EVOLUTION OF THE LAKE EFFECT(!) RAIN.

OVERVIEW...A LARGE CUTOFF 500 MB LOW HAS MOISTURE AND SPOKES OF
ENERGY ROTATING AROUND IT, WITH MOISTURE STRETCHING BACK INTO THE
BOUNDARY WATERS REGION OF MINNESOTA. THE 1000-850 MB LAYER WIND IS
PRODUCING SHOWERS IN THE FAVORED NW FLOW AREAS, BUT OPPOSED TO LES
WITH 20:1 RATIOS, THE RAIN HAS BEEN LIGHT.

TONIGHT...MODELS ARE IN PRETTY GOOD AGREEMENT THAT THE 500 MB LOW
WILL CONTINUE TO LIFT TO THE NE INTO QUEBEC/JAMES BAY OVER THE NEXT
12 HOURS. THIS WILL PULL THE UPPER MOISTURE (700-500 MB LAYER) TO
THE EAST THROUGH THE NIGHT. HOWEVER, IT WON`T DO MUCH TO THE
PREVAILING 1000-850 MB PATTERN AS THE NW WIND, 80-90% RH IN THE 850-
700 MB LAYER, AND 850 MB TEMPERATURES AROUND +5C TO +6C WILL
CONTINUE. SO THE EVOLUTION OF THE SHOWERS WILL BE FROM THE SEMI-
ORGANIZED BANDS OF OPEN CELLULAR RAINS SHOWERS TO A MORE ORGANIZED
BANDED STRUCTURE AFTER THE SUN SETS AND THE HEATING OF THE DAY IS
LOST. GOT THE BASIC IDEA OF THE RAIN SHOWERS INTO THE REGION SLOWLY
MOVING FROM THE WNW FLOW PATTERN OF EARLIER THIS AFTERNOON TO A NW
PATTERN TO ALMOST A NNW FLOW PATTERN BY 12Z.

&&

.SHORT TERM...(WEDNESDAY THROUGH FRIDAY)
ISSUED AT 347 PM EDT TUE AUG 25 2015

...SUMMER NOT DONE JUST YET...

HIGH IMPACT WEATHER: NONE

PATTERN OVERVIEW/FORECAST: LONG WAVE TROUGHING REMAINS IN PLACE
ACROSS WESTERN CANADA...DIPPING INTO THE WEST COAST OF THE
CONUS...DOWNSTREAM FROM A STRENGTHENING BLOCKING HIGH NEAR 165W
(POSSIBLY AIDED BY REMNANTS OF TROPICAL CYCLONE ATSANI IN THE
WESTERN PACIFIC). A COUPLE OF DEEP CUTOFF LOWS NOTED ACROSS NOAM.
ONE FAIRLY DEEP CUTOFF LOW IS MAKING IT/S WAY DOWN THE WEST COAST OF
NOAM...AND OF COURSE ANOTHER DEEP CUTOFF SYSTEM IS OVER THE GREAT
LAKES TODAY. INTERVENING RIDGING IS IN PLACE THROUGH THE WESTERN-
CENTRAL CONUS WITH ACTIVE MONSOON CONDITIONS IN THE SOUTHWEST.

LONG WAVE TROUGHINESS IS FORECAST TO DEEPEN ALONG THE WESTERN CONUS
AND INTO THE FAR EASTERN PACIFIC OVER THE NEXT SEVERAL DAYS...
SPURRED ON BY A COUPLE STRONG PIECES OF ENERGY AND ATTENDING COLD
AIR GETTING FORCED DOWN THROUGH ALASKA INTO THE WEST COAST. THIS IN
TURN WILL PUSH RIDGING/MUCH WARMER AIR THROUGH THE PLAINS AND
ULTIMATELY INTO THE EASTERN CONUS/GREAT LAKES BY EARLY NEXT WEEK.
CUTOFF LOW IN THE GREAT LAKES WILL SLOWLY OPEN AND TRANSLATE
NORTHEASTWARD OUT OF THE REGION OVER THE NEXT FEW DAYS...REPLACED BY
HIGH PRESSURE/RIDGING AND WARMER CONDITIONS. SO...SUMMER IS NOT DONE
YET AND IN FACT WE COULD SEE SOME FAIRLY WARM CONDITIONS
(BACK INTO THE 80S?) HEADING INTO THE FIRST WEEK OF SEPTEMBER.

WEDNESDAY/WEDNESDAY NIGHT...SHOULD BE THE LAST DAY OF THE COOL/
SHOWERY WEATHER. VERTICALLY STACKED LOW WILL BE NEAR THE SRN END OF
JAMES BAY WEDNESDAY MORNING BUT EXPECTED TO SLOWLY OPEN AND MOVE
INTO QUEBEC AS WE GO THROUGH THE DAY. NW/NNW CYCLONIC FLOW/ABUNDANT
MOISTURE WILL ALSO STILL BE IN PLACE WEDNESDAY MORNING WITH CYCLONIC
FLOW GRADUALLY LOSING IT/S GRIP THROUGH THE DAY AS WELL. FORECAST
SOUNDINGS SHOW GRADUAL LOW-MID LEVEL WARMING TONIGHT AND LOWERING
INVERSION HEIGHTS SUGGESTING LAKE EFFECT RAIN SHOWERS WILL BE ON A
DOWNWARD TREND THROUGH WEDNESDAY MORNING. BUT AS WE KNOW...WHEN IT
COMES TO LAKE EFFECT...WHEN YOU THINK IT MIGHT END...ADD ANOTHER 6
TO 12 HOURS TO THE FORECAST. NONETHELESS...WITH INCREASINGLY
MARGINAL OVER WATER INSTABILITY AND DECREASING CONVECTIVE CLOUD
DEPTH...WILL KEEP LAKE EFFECT RAIN/DRIZZLE CHANCES ON THE LOW SIDE
AND FOR JUST WEDNESDAY MORNING...FOCUSED IN THOSE NNW LAKE EFFECT
AREAS. STILL A RATHER CLOUDY DAY ON TAP THANKS TO A DAYTIME HEATING
COMPONENT TO THE CLOUD COVER AND A SLOW WESTWARD PUSH OF DRY AIR
INTO THE GREAT LAKES.

BIGGER FORECAST QUESTION BECOMES...HOW MUCH CLEARING DO WE REALIZE
WEDNESDAY NIGHT. MODEL GUIDANCE IS RATHER BULLISH IN HOLDING LOW
LEVEL MOISTURE (CLOUDS) BACK ACROSS THE CWA THROUGH A LARGE PART OF
THE NIGHT WITH COOL LOW LEVEL AIR AND A MODEST N/NW LAKE COMPONENT
IN PLAY. THIS WILL OF COURSE HAVE A LARGE IMPACT ON LOW TEMPS. IF
SOME INLAND LOCATIONS CAN CLEAR OUT...THERE IS THE POSSIBILITY WE SEE
SOME LOWER 40S BY THURSDAY MORNING. HAVE KEPT SLIGHTLY HIGHER LOW
TEMPS THINKING CLOUD COVER WILL BE AN ISSUE.

THURSDAY/THURSDAY NIGHT...PROBABLY THE NICEST WEATHER DAY/NIGHT THIS
WEEK AS HIGH PRESSURE/DRY AIR FINALLY TAKE CHARGE. PARTLY TO MOSTLY
SUNNY SKIES AND DAYTIME TEMPS WARMING BACK INTO THE 70S. ENJOY.

FRIDAY...SOME FORECAST UNCERTAINTIES CREEP INTO THE PICTURE TO WRAP
UP THE WORK WEEK. ALL GUIDANCE SOURCES LATCH ONTO A PIECE OF SHORT
WAVE ENERGY IN THE DESERT SW TODAY...PULL IT OVER TOP THE WESTERN
CONUS RIDGE...AND INTO THE MIDWEST/WESTERN GREAT LAKES ON FRIDAY.
COUPLED WITH INCREASING WARM ADVECTION ON THE BACKSIDE OF HIGH
PRESSURE IN THE WESTERN GREAT LAKES...THIS MIGHT PUSH SOME SHOWERS
INTO THE REGION DURING THE DAY. BUT...THAT/S PUTTING A LOT OF
CONFIDENCE IN THE GUIDANCE GETTING THAT RIGHT ON AND WE WILL JUST
HAVE TO SEE HOW IT GOES. INHERITED SOME LOW END CHANCES FOR SHOWERS
AND HAVE NO GOOD REASON TO CHANGE MUCH AT THIS POINT. BUT
OTHERWISE...WARMER WEATHER FOR FRIDAY IS A BETTER CERTAINTY WITH
HIGHS SOLIDLY IN THE 70S.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE AUG 25 2015

THE PATTERN CHANGE CONTINUES WITH WESTERN TROUGHING LEADING TO
DOWNSTREAM RIDGING ACROSS THE GREAT LAKES AND EAST COAST. THIS SETUP
WILL LEAD TO WARMER TEMPERATURES AND MAINLY DRY WEATHER THROUGH THE
PERIOD. THE EXCEPTION TO THIS WILL BE ENERGY CURRENTLY IN THE
SOUTHWESTERN STATES SNEAKING UP HERE DURING THE FRIDAY INTO SATURDAY
TIME FRAME. THIS WILL LEAD TO CHANCES FOR SHOWERS DURING THAT TIME.
THUNDER CHANCES LOOK LOW WITH NORTHERN MICHIGAN APPEARING TO BE ON
THE COOL SIDE OF THIS SYSTEM BUT THAT COULD CHANGE DEPENDING UPON
THE ACTUAL TRACK AND THERE IS PLENTY OF TIME TO MAKE ADJUSTMENTS.
LOOKING FARTHER AHEAD...THE RIDGE LOOKS LIKE IT WILL STRENGTHEN
LATER NEXT WEEK AND INTO LABOR DAY WEEKEND AS WELL YIELDING ABOVE
NORMAL TEMPERATURES. OVERALL A WARM SUMMERLIKE PATTERN IS EXPECTED
FROM DAYS 3 TO 10 INTO THE FUTURE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 744 PM EDT TUE AUG 25 2015

MAINLY MVFR CIGS INTO WED MORNING (IFR AT TIMES TVC)...THEN
IMPROVING.

LOW PRESSURE NEAR JAMES BAY CONTINUES TO VERY SLOWLY WEAKEN. HIGH
PRESSURE IN THE PLAINS WILL GRADUALLY MOVE EAST AS THE LOW MOVES
OUT AND FURTHER WEAKENS. BUT IT WILL TAKE UNTIL WED AFTERNOON
BEFORE WE SEE MUCH IMPROVEMENT HERE. UNTIL THEN...MVFR CIGS WILL
CONTINUE...ALONG WITH OCCASIONAL -SHRA/-DZ. IFR VSBYS ARE POSSIBLE
IN HEAVIER PRECIP FROM TIME-TO-TIME...WITH TVC THE MOST LIKELY TO
BE IMPACTED.

NW WINDS IN THE 5-12KT RANGE.

&&

.MARINE...
ISSUED AT 347 PM EDT TUE AUG 25 2015

TONIGHT THROUGH THURSDAY...TONIGHT THE WINDS WILL CONTINUE WITH THE
SMALL CRAFT WINDS AND WAVES AS THE LOW PRESSURE AREA CONTINUES TO
MOVE TO THE NE. WINDS LOOK LIKE THEY SHOULD BEGIN TO DIMINISH FROM
WEST TO EAST, SO THE SMALL CRAFT ADVISORIES WILL BE LIFT FROM LAKE
MICHIGAN TO LAKE HURON. WILL EXPECT THAT THE WAVES WILL CONTINUE ON
THE LAKE HURON SIDE THROUGH PART OF THE DAY AS WELL. WEDNESDAY
NIGHT, THE WINDS WILL CONTINUE TO DIMINISH AS HIGH PRESSURE BEGINS
TO BUILD INTO THE REGION. THURSDAY, THE HIGH WILL MOVE TO EAST AND
SOUTHWEST WINDS WILL BEGIN TO INCREASE. HOWEVER, AT THIS TIME, IT
LOOKS LIKE THE WIND SHOULD REMAIN BELOW SMALL CRAFT CRITERIA.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR LHZ345.

     SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR LHZ347-348.

LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR LMZ323-342-344.

LS...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR LSZ321.

&&

$$

NEAR TERM...JSL
SHORT TERM...ADAM
LONG TERM...SULLIVAN
AVIATION...JAZ
MARINE...JSL


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