Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 070601
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
201 AM EDT THU MAY 7 2015

.UPDATE...
ISSUED AT 945 PM EDT WED MAY 6 2015

ANOTHER QUIET NIGHT ACROSS THE NORTHWOODS WITH HIGH PRESSURE OFF
TO OUR EAST BUT STILL DOMINATING THE WX ACROSS OUR AREA. RETURN
FLOW ON THE BACK SIDE OF THE SURFACE HIGH HAS INCREASED SURFACE
DWPTS...WHICH WILL LIKELY LEAD TO SOME PATCHY FOG DEVELOPMENT
OVERNIGHT. OTHERWISE...PARTLY TO MOSTLY CLEAR SKIES EXPECTED...AS
TEMPS FALL INTO THE MID 40S TO LOWER 50S.

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 416 PM EDT WED MAY 6 2015

OVERVIEW...SFC HIGH PRESSURE OVER LAKE HURON IS STILL KEEPING THE
DRY AIR OVER N MICHIGAN THIS AFTERNOON. THIS COUPLED WITH THE 500 MB
RIDGE IN THE UPPER GREAT LAKES, HAS HELPED KEEP THE RAIN SHOWERS TO
A MINIMUM OVER THE FORECAST AREA. MOST CLOUD HEIGHT HAVE BEEN AT
10000 FT OR GREATER, SO WHAT RAIN HAS FALLEN, LOOKS TO HAVE BEEN
MAINLY SPRINKLES. THIS AFTERNOON STARTED OUT AS FAIRLY DRY, BUT AS
THE WARM FRONT/WARM SECTOR HAS MOVED INTO THE REGION THE SFC
MOISTURE HAS BEEN GOING BACK UP WITH TIME AND ADVANCING EASTWARD.

DETAILS FOR TONIGHT...THE 500 MB RIDGE AXIS WILL BE OVER MICHIGAN BY
12Z, PUTTING US IN THE WARM SOMETIME OVERNIGHT AS SHOWN BY THE 850
MB TEMPERATURES ON THE MODELS. AS WE GET INTO THE WARM SECTOR, THE
700-500 MB LAYER RH IS EXPECTED TO FALL INTO THE 30-40% RANGE,
ALLOWING FOR THE SKIES, AT LEAST IN THE MID AND UPPER LEVELS TO
CLEAR. HOWEVER, THE MOISTURE AT THE SFC AND 850 MB WILL BE "STEWING"
A BIT, AND AS THE WINDS DECOUPLE AND THE SKY CLEARS IN THE EVENING,
RADIATIONAL COOLING WILL PRODUCE PATCHY FOG AS THE LOW TEMPERATURES
FALL BELOW THE CROSS OVER TEMPERATURES (DEWPOINT AT THE HEAT OF THE
DAY). THE MOST LIKELY PLACE FOR THIS TO HAPPEN WILL BE ALONG THE
LAKE HURON SHORE LINE AS THE ONSHORE FLOW HAS BEEN ABLE TO KEEP
THINGS MOIST WITH THE MARINE LAYER, BUT AFTER DECOUPLING THIS
EVENING, THE SFC TEMPERATURES ARE EXPECTED TO FALL IN THE MID 40S.
THE WEST SIDE OF THE STATE WON`T AS SUSCEPTIBLE TO FOG AND LOW CLOUDS
AS THE LOW TEMPERATURES ARE EXPECTED TO REMAIN ABOVE 50. THE MIDDLE
OF THE STATE WILL HAVE PATCHY FOG AND LOW CLOUDS.

&&

.SHORT TERM...(THURSDAY THROUGH SATURDAY)
ISSUED AT 416 PM EDT WED MAY 6 2015

...WARM/BREEZY THURSDAY WITH INCREASING RAIN CHANCES TO END THE
WEEK...

HIGH IMPACT WEATHER POTENTIAL: ELEVATED FIRE DANGER THURSDAY.  NON-
SEVERE THUNDERSTORMS THURSDAY NIGHT THROUGH SATURDAY.

PATTERN SYNOPSIS/FORECAST: NORTH AMERICAN PATTERN UNDERGOING
AMPLIFICATION THIS AFTERNOON.  MEAN TROUGHING ACROSS THE WEST
CONSISTING OF AN EJECTING SOUTHERN BRANCH SHORT WAVE TROUGH EMERGING
OVER THE CENTRAL/SOUTHERN PLAINS...AND A DIGGING NORTHERN BRANCH
WAVE OVER THE PACIFIC NORTHWEST.  IN RESPONSE...RIDGING IS BUILDING
NORTHWEST FROM THE SOUTHEASTERN STATES INTO THE UPPER MIDWEST/UPPER
GREAT LAKES.  LARGER UPPER VORTEX SPINNING FARTHER OUT ACROSS THE
CENTRAL PACIFIC EAST OF THE DATELINE...WHILE QUASI-TROPICAL
DEVELOPMENT WAS OCCURRING OFF THE EAST COAST OF FLORIDA.  LATEST
SURFACE ANALYSIS SHOWS THE GREAT LAKES SANDWICHED BETWEEN TWO
FRONTS...ONE OVER NORTHERN ONTARIO AND A SECOND ACROSS THE OHIO
VALLEY WESTWARD INTO SOUTHWEST IOWA/SOUTHERN SOUTH DAKOTA WITH A
BROAD AREA OF LOW PRESSURE SPANNING THE HIGH PLAINS.  PLUME OF
DEEPER MOISTURE HAS EXPANDED NORTH INTO THE DAKOTAS/MINNESOTA AND
INTO SOUTHERN WISCONSIN/SOUTHERN LOWER MICHIGAN...WITH A RETREATING
POCKET OF DRY AIR ACROSS LAKE SUPERIOR/EASTERN UPPER MICHIGAN/LAKE
HURON.

SPLIT LONG WAVE TROUGH TAKES UP RESIDENCE ACROSS WESTERN NORTH
AMERICA FOR THE END OF THE WEEK...WITH CURRENT NORTHERN BRANCH WAVE
BECOMING A CLOSED LOW IN THE SOUTHERN BRANCH OVER CALIFORNIA/GREAT
BASIN/SOUTHWESTERN U.S. BY FRIDAY...SEPARATE FROM A NORTHERN BRANCH
SHORT WAVE TROUGH OVER ALBERTA/SASKATCHEWAN.  SHORT WAVE RIDGING
WILL MOVE EAST OF THE UPPER LAKES BY FRIDAY WITH SOUTHWESTERLY FLOW
ALOFT EMANATING FROM AROUND THE SOUTHERN BRANCH UPPER LOW CROSSING
THE REGION FRIDAY.  THIS SAME BASIC SET UP WILL STRETCH INTO THE
WEEKEND WITH A SLOW EASTWARD PROGRESSION AS WAVELENGTH SHRINKS
BETWEEN THE WESTERN SPLIT TROUGH AND THE UPPER LOW OVER THE CENTRAL
PACIFIC.  BETTER RETURN FLOW TRAJECTORY INTO MICHIGAN BY THURSDAY AS
PRESSURES FALL ACROSS THE PLAINS/UPPER MIDWEST AND SOUTHERLY FLOW
STRENGTHENS.  WARMER AND MORE MOIST AIR WILL LIFT INTO THE FORECAST
AREA THURSDAY....ALLOWING THE BAROCLINIC ZONE ACROSS NORTHERN
ONTARIO TO BECOME MORE PRONOUNCED AND THE BOUNDARY TO OUR SOUTH THIS
AFTERNOON TO WEAKEN.  A COLD FRONT WILL PUSH SLOWLY EAST INTO THIS
WARM AIR MASS...LIKELY NOT REACHING THE FORECAST AREA UNTIL FRIDAY
EVENING.  THIS BOUNDARY MAY TAKE SOME TIME CROSSING THE STATE
SATURDAY WITH THE POSSIBILITY OF A FRONTAL WAVE DEVELOPING AND
SLIDING NORTHEAST ALONG THE FRONT...WHICH WILL HINDER ITS PROGRESS.

PRIMARY FORECAST CONCERNS: WARMER TEMPERATURES AND INCREASING
WINDS/DEEP MIXING ON FIRE DANGER...AND POSSIBILITY OF SOME HIGH
BASED SHOWERS POPPING DURING THE AFTERNOON.  PRECIP THREAT FROM
THURSDAY NIGHT ONWARD.

THURSDAY...INCREASED WARMTH AND HUMIDITY ANTICIPATED THURSDAY AS
WARM AIR MASS SOUTH OF THE BOUNDARY OVER THE OHIO VALLEY ADVECTS
NORTH AS FRONT ITSELF ESSENTIALLY MIXES OUT.  STEEP LOW LEVEL LAPSE
RATES NEAR/SOUTH OF THE FRONT (E.G., 12Z DVN/ILX/ILN SOUNDINGS)...
AND PLENTY OF CUMULUS CLOUDS BUBBLING UP ACROSS THE OHIO VALLEY AND
WOULD EXPECT A SIMILAR SITUATION ACROSS NORTHERN MICHIGAN THURSDAY
AFTERNOON.  MODEST AMOUNT OF INSTABILITY (ON THE ORDER OF 500 J/KG
MLCAPE) SO PROBABLY CAN`T RULE OUT THE POTENTIAL FOR SOME SHOWERS
TRYING TO POP DURING THE HEATING OF THE DAY...UPSTREAM OFFICES DON`T
SEEM ALL THAT ENTHRALLED WITH THE IDEA SO WILL LEAVE IT OUT OF THE
FORECAST BUT THIS IS SOMETHING WORTH MONITORING TOMORROW.  SO AFTER
SOME MORNING FOG IN SPOTS WILL BUBBLE UP INTO A CUMULUS DECK DURING
THE LATE MORNING HOURS.  TEMPERATURES WILL WARM WELL INTO THE 70S-
AROUND 80 AWAY FROM THE LAKES...AND DEEP MIXING WILL PULLER HIGHER
MOMENTUM DOWN DURING THE AFTERNOON WITH GUSTS OVER 20 MPH FROM THE
SOUTH/SOUTHWEST.  THE ONLY THING PREVENTING FULL-ON RED FLAG
CRITERIA WILL BE DEW POINTS IN THE 50S.  BUT CRITERIA WILL REACH AN
ELEVATED FIRE DANGER MENTION IN THE HAZARDOUS WEATHER OUTLOOK.
SOUTHWESTERLY LOW LEVEL SETS UP THURSDAY NIGHT ACROSS THE UPPER
MISSISSIPPI VALLEY INTO UPPER MICHIGAN...MAY SERVE AS AN IMPETUS FOR
CONVECTIVE DEVELOPMENT ALONG WITH A SHORT WAVE TROUGH LIFTING
NORTHEAST WITHIN THE SOUTHERN BRANCH FLOW.  BUT NOT CERTAIN AS TO
HOW MUCH OF THIS MIGHT REACH THE FORECAST AREA (ONE CAN CERTAINLY
ARGUE NOT MUCH ESPECIALLY ACROSS NORTHEAST LOWER).  WILL MAINTAIN
LOW CHANCE POPS FOR EASTERN UPPER/NORTHWEST LOWER THURSDAY NIGHT.

FRIDAY...PROBABLY A BETTER CHANCE FOR RAIN FRIDAY AS TAIL END OF
AFOREMENTIONED SHORT WAVE TROUGH SWINGS THROUGH...DRAGGING/
DEVELOPING SHOWERS AND THUNDERSTORMS THROUGH AS IT DOES.  WILL BE
ANOTHER WARM DAY THOUGH A LOT WILL DEPEND ON EVOLUTION OF
PRECIPITATION SO WILL BE A LITTLE MORE CONSERVATIVE WITH FORECAST
HIGHS AT LEAST ACROSS EASTERN UPPER/NORTHWEST LOWER (AROUND 70-MID
70S VERSUS UPPER 70S-AROUND 80 NORTHEAST LOWER).  ANOTHER SHORT WAVE
TROUGH COMING THROUGH THE UPPER MIDWEST/UPPER GREAT LAKES FRIDAY
NIGHT...ALONG WITH THE SURFACE COLD FRONT AND ATTENDANT FRONTAL WAVE
MOVING INTO LOWER MICHIGAN...WILL BRING AN ADDITIONAL CHANCE FOR
SHOWERS AND THUNDERSTORMS.

SATURDAY...TEMPTING TO CONFINE RAIN CHANCES SATURDAY TO THE MORNING
HOURS...WITH SHORT WAVE AND COLD FRONT PASSAGE DURING THE AFTERNOON.
BUT THAT IS PROBABLY TOO CUTE THREE DAYS OUT...SO WILL CONTINUE WITH
MOSTLY GENERIC SHOWER/THUNDERSTORM CHANCES FOR THE DAY SATURDAY
ALONG WITH COOLER TEMPERATURES.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 PM EDT WED MAY 6 2015

TEMPERATURES WILL RETURN TO NORMAL READINGS TO BEGIN THE WORK
WEEK...AS THE NRN PLAINS STORM SYSTEM WHICH GENERATED WELL ABOVE
NORMAL TEMPERATURES ACROSS NRN MI INTO THE WEEKEND...FINALLY EXITS
INTO QUEBEC. 850MB TEMPS WILL DROP FROM +12C/14C SATURDAY TO
+8C/10C SUNDAY AND FINALLY TO AROUND 0C/+2C TUESDAY AND WEDNESDAY.
OVERALL WILL MENTION NEARLY SEASONAL TEMPS IN THE 60S SUNDAY AND
MONDAY...BEFORE FALLING TO BELOW NORMAL READINGS IN THE 50S
TUESDAY AND WEDNESDAY. FAIRLY UNSTABLE PATTERN ACRS THE GREAT
LAKES THROUGH THE PERIOD AS A STORM SYSTEM AND UPPER LOW IN THE
PLAINS LIFTS INTO THE STATE BY TUESDAY. OVERALL WILL CONTINUE WITH
CURRENT FCST TREND OF HIGH CHC OF SHOWERS THROUGH THE PERIOD...
WHILE MENTIONING THUNDERSTORMS SUNDAY AND MONDAY AS MID LVL DEW
PTS CLIMB TO AROUND 14C.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 145 AM EDT THU MAY 7 2015

...SOME ACTIVE WEATHER POSSIBLE...

SFC HIGH PRESSURE IS MOVING EAST...WITH A WEAK SE FLOW ACROSS THE
REGION. LOW PRESSURE WAS WELL WEST IN THE CENTRAL PART OF THE
COUNTRY...WITH SOME HIGH CLOUDS DRIFTING OVERHEAD AND AN INCREASE
IN WINDS JUST OFF THE SFC...BUT JUST BELOW LLWS CRITERIA. STILL
LOOKING AT THE POSSIBILITY OF FOG DEVELOPMENT OVERNIGHT WITH GOOD
RADIATIONAL COOLING AND INCREASED SFC BASED MOISTURE...AND A
POSSIBLE LIFR CIG. TEMP/DEW POINT SPREADS STILL TOO HIGH...AND
HAVE DELAYED THE ONSET.

WHATEVER CAN DEVELOP THROUGH DAYBREAK WILL DISSIPATE QUICKLY IN
STILL DRY AIR MASS AND UNSTABLE LOW LEVELS ALLOWING FOR GOOD
MIXING AND RESULTANT AFTERNOON WIND GUSTS OUT OF THE SOUTH/SSE AT
16-18KTS. WINDS WILL TRY AND TURN ONSHORE ACROSS NE LOWER THIS
AFTERNOON AND RESULT IN SOME LOW LEVEL CONVERGENCE AND AN OUTSIDE
SHOT AT LATE DAY ISOLATED SHOWERS NEAR APN.

TONIGHT....LOW PRESSURE DRIFTS INTO ONTARIO WITH A TRAILING COLD
FRONT INTO THE MISSISSIPPI VALLEY. CHANCES FOR SHOWERS AND A FEW
STORMS INCREASE AS WELL...BUT THERE IS MORE CONFIDENCE IN THE
DEVELOPMENT OF LLWS. THAT HAS BEEN INTRODUCED INTO THE TAFS.

&&

.MARINE...
ISSUED AT 416 PM EDT WED MAY 6 2015

TONIGHT THROUGH FRIDAY...HIGH PRESSURE WILL MOVE OVER LAKE HURON AND
CONTINUE EAST OVERNIGHT INTO ONTARIO AS WARMER, MORE HUMID AIR MOVES
OVER THE UPPER GREAT LAKES. WHILE THE WINDS WILL BE LIGHT OVERNIGHT,
THE EXTRA MOISTURE MAY CAUSE PATCHY FOG OVER THE GREAT LAKES,
ESPECIALLY OVER LAKE HURON DUE TO THE LAST OF WIND. FOG MAY FORM ON
LAKE MICHIGAN, BUT DURING THURSDAY, THE WINDS WILL INCREASE AS THE
PRESSURE GRADIENT TIGHTENS OVER THE UPPER GREAT LAKES, WHICH SHOULD
MIX OUT ANY FOG DURING THE AFTERNOON. WITH THE INCREASE IN WIND,
SMALL CRAFT ADVISORIES MAY BE NEEDED FROM WIND GUSTS UP TO 25 KNOTS,
WHICH WILL CONTINUE ON INTO THURSDAY EVENING. WINDS MAY INCREASE
AGAIN ON FRIDAY AS ANOTHER SYSTEM MOVES THROUGH THE UPPER GREAT
LAKES.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...MLR
NEAR TERM...JSL
SHORT TERM...JPB
LONG TERM...SWR
AVIATION...SMD
MARINE...JSL



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