Area Forecast Discussion
Issued by NWS Gaylord, MI

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736
FXUS63 KAPX 211049
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
649 AM EDT THU MAY 21 2015

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 432 AM EDT THU MAY 21 2015

...VARIABLE CLOUDS TODAY WITH A SMALL SHOWER CHANCE/COLD AGAIN
TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: ELEVATED FIRE DANGER THIS AFTERNOON.
MORE FREEZING LOW TEMPERATURES FRIDAY MORNING.

PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS
A 1029MB HIGH CENTERED OVER THE NEBRASKA PANHANDLE THAT EXTENDS EAST
ACROSS THE CENTRAL PLAINS/MIDWEST...ACROSS SOUTHERN LOWER MICHIGAN
AND INTO PENNSYLVANIA/NEW JERSEY.  AN EAST-WEST FRONT STRETCHES
ACROSS NORTHERN QUEBEC/NORTHERN ONTARIO WEST ACROSS FAR NORTHERN
MINNESOTA/NORTH DAKOTA WITH A 1012MB FRONTAL WAVE ALONG THE
NORTHWEST SHORE OF LAKE SUPERIOR.  THERE IS A BIT OF A SURFACE
TROUGH THAT EXTENDS SOUTH FROM THIS SURFACE LOW INTO CENTRAL
UPPER/NORTHEAST WISCONSIN.  LOW LEVEL AIR MASS WAS PRETTY DRY PER
00Z APX/GRB SOUNDINGS (DEW POINT DEPRESSIONS AROUND 20C BELOW
600MB)...WITH A MOIST LAYER IN THE 500-350MB LAYER AT APX.  INL
SOUNDING SHOWS A DEEP MIXED LAYER AHEAD OF THE COLD FRONT (UP TO
650MB).  WATER VAPOR IMAGERY SHOWS SEVERAL SHORT WAVE TROUGHS ACROSS
THE UPPER MIDWEST/UPPER GREAT LAKES...AND ANOTHER DROPPING SOUTH
TOWARD FAR NORTHERN NORTH DAKOTA/MINNESOTA.  THESE WAVES ARE
SPREADING AN ALTOCUMULUS DECK ACROSS NORTHERN LOWER...WITH SOME RAIN
ACROSS FAR SOUTHEAST LOWER AND INTO THE UPPER OHIO VALLEY.  BROKEN
EAST-WEST BAND OF MID CLOUDS ALSO STRETCHED OUT ALONG THE FRONT TO
THE NORTH.

COLD FRONT DROPS SOUTH ACROSS THE FORECAST AREA DURING THE DAY
TODAY...PUSHING INTO SOUTHERN LOWER MICHIGAN BY THIS EVENING.
ABOVE MENTIONED STEEPER LAPSE RATES BELOW 650MB WILL ALSO SPREAD
ACROSS NORTHERN MICHIGAN TODAY.  ANOTHER PUSH OF COLDER AIR EXPECTED
TO SPREAD INTO THE REGION TONIGHT WITH HIGH PRESSURE BUILDING IN
FROM THE NORTH.

PRIMARY FORECAST CONCERNS: CLOUDS AND ANY PRECIP CHANCE TODAY ALONG
SOUTHWARD DROPPING COLD FRONT.  POSSIBLE ELEVATED FIRE DANGER ISSUES
THIS AFTERNOON.  LOW TEMPERATURES FRIDAY MORNING AND FROST POTENTIAL.

TODAY...FIRST OFF...WILL DROP CURRENT FREEZE HEADLINES AT FORECAST
ISSUANCE...TEMPERATURES STILL IN THE 40S MOST AREAS AND THESE SORTS
OF HEADLINES ARE BEST HEEDED THE NIGHT BEFORE (PRETTY SURE NO ONE IS
JUMPING OUT OF BED AT 5 AM TO COVER THEIR PETUNIAS).  COLD FRONT
CURRENTLY MAKING ITS WAY INTO LAKE SUPERIOR...AND IS EXPECTED TO
DROP THROUGH THE UPPER PENINSULA THIS MORNING AND INTO NORTHERN
LOWER THIS AFTERNOON.  SOME LOW LEVEL FORCING WILL BE PREVALENT
TODAY ASSOCIATED WITH THE FRONTAL ZONE...WITH DOWNWARD FORCING IN
UPPER LEVELS BEING ON THE BACKSIDE OF THE DEPARTING SHORT WAVE
TROUGH.  DESPITE DEEP LAYER MIXING AHEAD OF THE FRONT NOT MUCH
INSTABILITY EXPECTED ACROSS NORTHERN MICHIGAN AHEAD OF THE FRONT...A
LITTLE BETTER MOISTURE ACROSS WISCONSIN (0-1KM MEAN MIXING RATIO 5-
6G/KG) EXPECTED TO SQUEEZE OUT A LITTLE MORE INSTABILITY ON THE
OTHER SIDE OF THE LAKE.  BUT HIGH BASED CLOUDS (AC/ACCAS) AT THE TOP
OF THE MIXED LAYER EXPECTED ALONG/BEHIND THE FRONT...PROBABLY SOME
VIRGA/SPRINKLES AS WELL UNLESS A HEAVIER SHOWER CAN PENETRATE DRY
MIXED LAYER.  POSSIBLE THAT MORE SUBSTANTIAL SHOWERS OVER NORTHERN
WISCONSIN WILL ADVECT INTO NORTHWEST LOWER LATE IN THE DAY...AND
THIS MAY BE THE BEST AREA TO CARRY SOME SCATTERED POPS LATER THIS
AFTERNOON.  OTHERWISE WILL SEE MORE CLOUDS TO START THE DAY ACROSS
EASTERN UPPER WITH MORE SUN THIS AFTERNOON...WHILE MORE SUN TO START
BELOW THE BRIDGE AND MORE CLOUDS DURING THE AFTERNOON.  WINDS
EXPECTED TO BECOME GUSTY LATER TODAY...COMBINATION OF DEEP MIXING
AHEAD OF THE FRONT AND A PUSH OF COLD ADVECTION BEHIND THE PASSING
COLD FRONT THIS AFTERNOON.  WIND GUSTS 20-30MPH ANTICIPATED ACROSS
EASTERN UPPER/NORTHEAST LOWER.  ALONG WITH THE WIND WILL BE DEW
POINTS IN THE 30S AND PERHAPS MIXING DOWN INTO THE UPPER 20S WILL
LIKELY PUSH MINIMUM RELATIVE HUMIDITY VALUES BELOW 30 PERCENT...SO
THE COMBINATION OF THESE VARIABLES WILL LIKELY RESULT IN ELEVATED
FIRE DANGER.

TONIGHT...AS THE COLD FRONT CONTINUES TO PROGRESS SOUTH THIS EVENING
ANY LINGERING SHOWER THREAT OVER THE SOUTHERN PORTION OF THE
FORECAST AREA WILL END...WITH SKIES CLEARING OVERNIGHT.  THERE WILL
STILL BE A BIT OF A GRADIENT FOR MUCH OF THE NIGHT...BUT WINDS
SHOULD DECOUPLE LATE.  ADVECTION BY ITSELF WILL PUSH TEMPERATURES
INTO THE 30S...IF WINDS SLACK OFF COMPLETELY THEN MAY SEE A FEW
SPOTS DIP INTO THE 20S.  REGARDLESS...GOOD POSSIBILITY THAT WE`LL BE
DEALING WITH ANOTHER ROUND OF FREEZE HEADLINES FRIDAY MORNING (AND A
BETTER CHANCE WITHOUT CLOUD COVER AND A FRESH COOL AIR MASS SPILLING
IN).

&&

.SHORT TERM...(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 432 AM EDT THU MAY 21 2015

HIGH IMPACT WEATHER: ONE MORE NIGHT OF FROST AND FREEZE PROBLEMS
(FRIDAY). ELEVATED FIRE DANGER FRIDAY AND SATURDAY AFTERNOON.

FORECAST CHALLENGE: TRYING TO FIGURE OUT IF THE SKY CLEARS FRIDAY
NIGHT FOR ONE MORE SUB FREEZING MORNING.

(5/22)FRIDAY...STARTING OUT CHILLY WITH THE AROUND FREEZING
TEMPERATURES AND WITH THE NW WIND, AND THE 850 MB TEMPERATURE COLD
POOL DROPPING INTO THE UPPER GREAT LAKES WITH -6C AIR ON THE ECMWF
AND GFS, WILL EXPECT THAT THE 50S WILL BE THE HIGH TEMPERATURE.
HOWEVER, IT MAY NOT SEEM THAT COLD AS THE SUNSHINE LOOKS LIKE IT
WILL BE OUT IN FULL FORCE WITH THE 700-500 MB LAYER RH SUB 20% AND
THE 850 MB RH AROUND 40%. HOWEVER, THERE IS A FAIR AMOUNT OF DRY AIR
AT THE SFC AS THE SFC HIGH DROPS INTO THE FORECAST AREA. THIS WILL
DROP THE DEWPOINTS TO THE UPPER TEENS, ESPECIALLY IN THE HURON
FOREST AREA. SO THE MIN RH FOR THE AREAS WILL BE SUB-25%. WHILE THE
SUSTAINED WINDS WON`T GET MUCH OVER 10 MPH AT THE 20FT LEVEL, WILL
PROBABLY SEE SEVERAL HOURS OF FREQUENT GUSTS TO 15 MPH. SO WILL HAVE
THE ELEVATED WORDING IN THE HWOAPX FOR THE DAY.

OVERNIGHT, WITH THE DRYNESS, WE SET UP FOR A CLEAR NIGHT, AT LEAST
AT THE BEGINNING AND WITH THE SFC HIGH OVER THE REGION, WILL EXPECT
THAT THE WINDS WILL DECOUPLE. HOWEVER, THERE ARE A COUPLE OF KINKS
FOR THIS FREEZE NIGHT. THE CORE OF THE SFC HIGH IS SE OF THE STATE,
AND THE PRESSURE GRADIENT IS BEGINNING TO TIGHTEN UP A BUNCH ON THE
GFS, BUT NOT AS MUCH ON THE ECMWF. THIS COULD HALT THE TEMPERATURES
FROM FALLING AROUND THE LOWER 30S, AND ALLOW THEM TO RECOVER A BIT
BEFORE DAY BREAK. SECOND IS THE CLOUD COVER AS THE MODELS ARE
BRINGING 60-70% RH AT 850 MB FROM UPSTREAM. SO THERE IS A RISK THAT
MY LOWS ARE TOO LOW, BUT THINK THAT THE UPPER 20S ARE ACHIEVABLE
AROUND MIDNIGHT OR 06Z. BEFORE THE WINDS KICK UP.

(5/23)SATURDAY...WHILE THE RETURN FLOW GET GOING, THE MOISTURE AT
THE SFC IS SLOW TO RESPOND, AND WE GET INTO ANOTHER ELEVATED FIRE
DANGER DAY AS THE 850 MB TEMPERATURES APPROACH 10C BY 00Z. THE GFS
IS TRYING TO BRING IN RAIN, AND CLOUDS AT 850 MB. THE ECMWF IS
SLOWER ON THAT, AND THINK THAT IS THE WAY TO GO AS THE SFC HIGH
RETREATING, THE GFS HAS BEEN TOO BULLISH ON BRINGING THE RAIN AND
MOISTURE BACK INTO THE UPPER GREAT LAKES. SO WITH SUNSHINE, AND
TEMPERATURES TO AROUND 70, WILL EXPECT THAT THE DEWPOINTS WILL FALL
INTO THE LOWER 30S, ALLOWING MIN RH TO FALL TO AROUND 25% OVER THE
EAST PART OF THE STATE. WINDS WILL BE UP HIGHER, WITH 20 FT WINDS IN
THE 10 TO 15 MPH RANGE AND FREQUENT GUSTS TO 20 MPH. TEMPERATURES
LOOK LIKE THEY SHOULD STAY BELOW 75F, BUT CAN`T RULE OUT AN ISOLATED
LOCATION GETTING OVER CRITICAL VALUES. OVERNIGHT, CONTINUED THE
SLOWNESS OF THE RAIN MOVING IN AS IT LOOKS LIKE THE LOWER PORTION OF
THE SOUNDINGS ON THE NAM AND ECMWF ARE FAIRLY DRY.

&&

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 432 AM EDT THU MAY 21 2015

EXTENDED (SUNDAY THROUGH WEDNESDAY)...AS WAS MENTIONED YESTERDAY,
THE PATTERN LOOKS TO BE SHIFTING SOME TO SOMETHING THAT IS A LITTLE
MORE REMINISCENT OF THE PAST FEW MONTHS. THAT IS A TROUGH NEAR THE
GREAT LAKES. HOWEVER, THE DIFFERENCE IS THE HIGH OVER LOW BLOCK ON
THE WEST COAST THAT LOOKS TO SIT OVER THE PACIFIC COAST, IN SOME
FORM THROUGH ROUGHLY NEXT WEEK. SO WHAT DOES THAT MEAN TO US? IT
FORCES A SOUTHERN BRANCH IN THE JET STREAM THAT WILL COME OUT OF THE
PACIFIC, AND THE RIDGE THAT WILL FUNNEL THE MAIN SHORTWAVES INTO THE
EASTERN TROUGH, AND BRING RAIN SHOWERS THROUGH THE UPPER GREAT
LAKES. WAS LEANING TOWARD AN ECMWF SOLUTION, AS THE GFS SEEMS
OVERLY WET, ESPECIALLY CONSIDERING THAT THE GFS HAS PREDICTED "WET"
EVENTS ONLY TO HAVE THE ECMWF SOMEWHAT LESSER EVENT TURN OUT TO
CLOSER TO THE TRUTH. SO WILL BACK OFF THE POPS A BIT ON SUNDAY,
ALLOW IT TO BE RAINING ON MONDAY, POSSIBLY TUESDAY, AND AGAIN ON
WEDNESDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM EDT THU MAY 21 2015

VFR CONDITIONS EXPECTED TODAY FOR THE MOST PART...PERHAPS A FEW
SHOWERS AROUND TVC AND ESPECIALLY MBL LATE THIS AFTERNOON/EARLY
EVENING.

&&

.MARINE...
ISSUED AT 432 AM EDT THU MAY 21 2015

INCREASING WINDS LATER TODAY AHEAD OF AND BEHIND A PASSING COLD
FRONT WHICH WILL LIKELY RESULT IN SMALL CRAFT CONDITIONS
DEVELOPING ON WHITEFISH BAY/ST. MARY`S RIVER AND MUCH OF THE LAKE
HURON NEARSHORE ZONES FOR THIS AFTERNOON THROUGH TONIGHT. WINDS
EXPECTED TO DIMINISH BY FRIDAY AS HIGH PRESSURE BUILDS INTO THE
UPPER LAKES.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 AM EDT FRIDAY FOR
     LHZ346>348.

LM...NONE.
LS...SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 AM EDT FRIDAY FOR
     LSZ321-322.

&&

$$

NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
MARINE...JPB



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