Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 051753
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
153 PM EDT TUE MAY 5 2015

.UPDATE...
ISSUED AT 1002 AM EDT TUE MAY 5 2015

THE CORE OF THE SFC HIGH IS ROOTED OVER THE FORECAST AREA WITH AN
MCS/WAA RAIN TO THE SOUTH OF THE FORECAST AREA ALONG AND SOUTH OF
THE US-10 CORRIDOR. AS WITH YESTERDAY, THE IDEA OF LOWER RELATIVEHUMIDITY
LOOKS RIGHT, BUT WILL BE TRICKY AS THE CLOUD SHIELD WILL LOWER THE
INSOLATION, AND THUS WE WON`T HEAT AS MUCH AND WE WON`T MIX AS
MUCH WHICH WILL LEAD TO SOMEWHAT HIGHER HUMIDITY LEVELS THAT FIRST
THOUGHT. THIS IS THE FORECAST CHALLENGE. HOWEVER, WILL FOR THE
TIME BEING LEAVE THE LOW RH VALUES, FOR NOW, AND WATCH THE CLOUD
TRENDS, AND SEE IF WE CAN START HEATING SOONER THAN LATER AND
POSSIBLY, MIX A LITTLE DEEPER. THINK THAT THE PRIME LOW RH TIME
WILL BE BETWEEN 4-6PM.

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 334 AM EDT TUE MAY 5 2015

ON THE LATEST SURFACE WEATHER MAP...1026 MB HIGH PRESSURE WAS RIDGED
FROM NORTHEAST WISCONSIN INTO NORTHWEST LOWER MICHIGAN.
MEANWHILE...1018 MB LOW PRESSURE WAS OVER SOUTHWEST IOWA WITH A
NEARLY STATIONARY BOUNDARY EXTENDING NORTHEAST INTO THE NORTHERN
OHIO VALLEY. SATELLITE IMAGERY SHOWED A MESOSCALE CONVECTIVE COMPLEX
COVERING NORTHEAST MISSOURI...MUCH OF ILLINOIS AND JUST INTO
NORTHWEST INDIANA. THE MAIN NEAR TERM FORECAST CONCERNS REVOLVE
AROUND NORTHWARD EXTENT OF CLOUDS AND POPS THROUGH TONIGHT FROM THE
SYSTEM TO OUR SOUTH AND HOW LOW RELATIVE HUMIDITY VALUES WILL FALL
THIS AFTERNOON.

TODAY INTO TONIGHT...SURFACE HIGH PRESSURE IS EXPECTED TO HOLD
STRONG ACROSS THE REGION WITH AT LEAST A COUPLE OF MESOSCALE
CONVECTIVE COMPLEXES MOVING BY TO THE SOUTH ALONG THE NEARLY
STATIONARY BOUNDARY ACROSS THE NORTHERN OHIO VALLEY. SOUTHERN ZONES
OF THE FORECAST AREA WILL SEE THE MOST AND THICKEST MAINLY HIGH
CLOUD COVER WHILE LITTLE HIGH CLOUDS EXTEND INTO EASTERN UPPER.
PRECIPITATION IS EXPECTED TO REMAIN JUST OFF TO OUR SOUTH THROUGH
TONIGHT (THOUGH IT MAY BE A CLOSE CALL ACROSS FAR SOUTHERN ZONES
LATER TONIGHT). ANOTHER WARM DAY TODAY WITH HIGHS OF WELL INTO THE
60S AWAY FROM THE LAKESHORES. RELATIVE HUMIDITY VALUES ARE STILL
EXPECTED TO DROP OFF TO UNDER 20 PERCENT INLAND DUE TO GOOD MIXING
OF DRY AIR ALOFT IN COMBINATION WITH DRY NORTHEAST FLOW OUT OF
EASTERN CANADA. THIS COULD PROVE PROBLEMATIC DUE TO THE EXTENDED
STRETCH OF DRY WEATHER DRYING OUT FINE FUELS...THOUGH WINDS SHOULD
REMAIN UNDER 10 MPH (WILL CONTINUE TO MENTION ELEVATED FIRE DANGER
IN THE HAZARDOUS WEATHER OUTLOOK). WILL CUT TEMPS TONIGHT BY A FEW
DEGREES WITH LIGHT WINDS LEADING TO GOOD RADIATIONAL COOLING. LOWS
EXPECTED TO RANGE FROM THE MIDDLE 30S TO THE MIDDLE 40S.

&&

.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 334 AM EDT TUE MAY 5 2015

HIGH IMPACT WEATHER POTENTIAL: FIRE WEATHER CONCERNS THROUGH
THURSDAY.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: THE EVOLUTION TO A MORE
AMPLIFIED/SLOWER PATTERN NOW UNDERWAY AS STRONG SHORTWAVE DIVES INTO
THE PACIFIC NORTHWEST. ALREADY STARTING TO SEE SOME SUBTLE
DOWNSTREAM HEIGHT RISES IN RESPONSE ACROSS THE PLAINS...A SIGN
ELONGATED SUBTROPICAL RIDGING IS BEGINNING ITS NORTHWARD BUILD. THIS
AMPLIFICATION LOOKS TO REACH MATURITY DURING MID AND LATE
WEEK...WITH DEEP TROUGHING BUILDING THROUGH THE WEST...ALL-THE-WHILE
DOWNSTREAM RIDGING BUILDS NORTH INTO ONTARIO. NORTHERN MICHIGAN
BECOMES INCREASINGLY CENTERED UNDER THE LATTER...HELPING BRING
ANOTHER SURGE OF EARLY SUMMER WARMTH BY THURSDAY AND KEEPING MOST OF
THE MUCH NEEDED WET WEATHER REMOVED TO OUR WEST. WHOLE PATTERN
BECOMES A TOUCH MORE PROGRESSIVE HEADING TOWARD THE WEEKEND...
PERHAPS (PERHAPS!) ALLOWING SOME MORE WIDESPREAD SHOWERS TO ADVANCE
ACROSS THE INCREASINGLY PARCHED NORTHERN MICHIGAN LANDSCAPE. WE CAN
ONLY HOPE.

PRIMARY FORECAST CONCERNS/CHALLENGES: ADDRESSING FIRE WEATHER
PARAMETERS (TEMPS/RH/WIND) THROUGH THURSDAY AND LATE WEEK/WEEKEND
SHOWER AND STORM CHANCES.

DETAILS: AMPLIFICATION PROCESS CONTINUES THROUGH WEDNESDAY...WITH
CURRENT DESERT SOUTHWEST SHORTWAVE GETTING THE BOOT NORTHEAST AS
STRONGER NORTHWEST PACIFIC WAVE DIGS IN. OVERHEAD RIDGING BY THEN
WILL BE QUITE FORMIDABLE..EASILY SHUNTING THIS LEAD WAVE WELL TO OUR
WEST THROUGH THURSDAY. UPSTREAM WAA WILL INCREASE IN THE PROCESS...
HELPING DRIVE WESTERN PORTION OF STALLED NORTHERN OHIO VALLEY
SURFACE FRONT NORTH. BEST MOISTURE ADVECTION/FORCED ASCENT ALL
FOCUSES TO OUR WEST WEDNESDAY AND THURSDAY WHERE MID LEVEL SUPPORT
COLLOCATES WITH IMPRESSIVE SOUTH/NORTH DIRECTED LOW LEVEL JET.
NOW...A FEW SHOWERS MAY ATTEMPT TO PUSH INTO THE SOUTHWEST SECTIONS
OF OUR AREA WEDNESDAY DURING INITIAL NORTHWARD PUSH OF THE SURFACE
FRONT. DYNAMICS ARE NOT IMPRESSIVE...AND LOW LEVEL AIRMASS WILL
REMAIN DRY. HAVE RUN WITH A SHOWER THREAT FOR THE LAST FEW DAYS
DURING THIS PERIOD. WILL KEEP SOME LIMITED MENTION...BUT IF IT DOES
RAIN...IT SURE WON`T BE MUCH. OTHERWISE...INHERITED DRY FORECAST
WEDNESDAY NIGHT THROUGH THURSDAY LOOKS GREAT AS OVERHEAD RIDGING
DOMINATES. MAY SEE SOME SHOWERS MAKE A RUN INTO AT LEAST THE
NORTHWEST HALF OF OUR AREA THURSDAY NIGHT. NOT REALLY
IMPRESSED...WITH NEARLY ALL MID LEVEL SUPPORT PUSHING WELL TO OUR
NORTH...LEAVING APPROACHING DYING COLD FRONT ADVANCING INTO AN
INCREASINGLY STABLE LOW LEVEL ENVIRONMENT TO DRIVE ADDITIONAL SHOWER
DEVELOPMENT. SEEN THIS BEFORE...WITH EXPERIENCE SUPPORTING JUST SOME
DECAYING SHOWERS ADVANCING INTO OUR AREA (SEE SUNDAY NIGHT).

AS FOR FIRE WEATHER: CONCERNS REMAIN...ESPECIALLY CONSIDERING JUST
HOW DRY SURFACE CONDITIONS ARE. NOT SEEING ANY POTENTIAL FOR RED
FLAG CONDITIONS (AT LEAST YET)...BUT LOW RH VALUES WEDNESDAY AND
THURSDAY (BETTER LOW LEVEL MOISTURE THURSDAY OFFSET BY HIGHS
REACHING THE 70S/NEAR 80) DEFINITELY SUPPORTS ELEVATED FIRE WORDING
IN OUR HAZARDOUS WEATHER PRODUCTS. INITIAL LIGHT WINDS WEDNESDAY
INCREASE OUT OF THE SOUTH THURSDAY AS THE PRESSURE GRADIENT BEGINS
TO TIGHTEN.

&&

.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 334 AM EDT TUE MAY 5 2015

LONG TERM (FRIDAY THROUGH MONDAY): HIGH UNCERTAINTY CONTINUES...WITH
THURSDAY NIGHTS FRONT POTENTIALLY STALLING ACROSS THE AREA...WAITING
FOR NEXT WESTERN WAVE AND ATTENDANT SURFACE RESPONSE TO RIDE UP
ALONG IT LATER FRIDAY/FRIDAY NIGHT. HIGH PRESSURE PUSHING ACROSS
SOUTHERN CANADA WILL HAVE PLENTY TO SAY ON JUST WHERE THIS FRONT
STALLS. SET-UP DEFINITELY OFFERS AT LEAST SOME GOOD RAIN
POSSIBILITIES...WITH GOOD MOISTURE INFLOW INTO THE SURFACE FRONT
SURGING PWAT VALUES AOA 1.25 INCH LEVELS. JUST NOT SURE WHERE
EVERYTHING WILL ALIGN...FORCING JUST GENERIC CHANCE SHOWER AND STORM
WORDING FOR NOW. SAME GOES FOR THE WEEKEND INTO THE START OF NEXT
WEEK...WITH EXACT FRONTAL PLACEMENT AND TIMING OF ADDITIONAL WAVES
PLAYING HAVOC ON MID RANGE GUIDANCE. WILL SIMPLY TAKE A GUIDANCE
CONSENSUS BLEND APPROACH...WHICH UNFORTUNATELY MEANS AN EXTENDED
STRETCH OF SHOWER AND STORM CHANCES (VERY UNLIKELY THIS WHOLE PERIOD
WILL BE WET).

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 144 PM EDT TUE MAY 5 2015

WITH HIGH PRESSURE OVER THE UPPER GREAT LAKES, WE WILL CONTINUE
WITH VFR CONDITIONS OVER THE NEXT 18 HOURS OR SO. HOWEVER, AROUND
BETWEEN 10Z AND 12Z WEDNESDAY, THE SFC HIGH WILL BEGIN TO RETREAT
TO THE EAST, AS A WARM FRONT MOVES INTO THE REGION. THIS WILL LEAD
TO AT LEAST MVFR CIGS OVER THE AREA AT MBL AND TVC AFTER 12Z. SOME
OF THE GUIDANCE WOULD SUGGEST THAT RAIN COULD BE FALLING AT THOSE
TAF SITES JUST AFTER 15Z, HOWEVER, FOR NOW AM CONFIDENT THAT THE
SPEED IS SLOWER AND THAT CONDITIONS SHOULD REMAIN DRY THROUGH 18Z.

&&

.MARINE...
ISSUED AT 334 AM EDT TUE MAY 5 2015

SURFACE HIGH PRESSURE ACROSS NORTHERN LOWER WILL BE SLOW TO DRIFT
OFF TO THE EAST THROUGH THURSDAY. THIS WILL PRODUCE A VERY SLACK
GRADIENT WITH A PREVAILING NORTHEAST FLOW AND AFTERNOON ONSHORE
FLOW. WINDS WILL VEER SOUTHERLY THURSDAY AND PICK UP A BIT AS THE
GRADIENT PICKS UP A LITTLE AS THE HIGH DEPARTS TO THE EAST.


&&

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

$$

UPDATE...JSL
NEAR TERM...SULLIVAN
SHORT TERM...MSB
LONG TERM...MSB
AVIATION...JSL
MARINE...SULLIVAN


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