Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 292010
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
410 PM EDT WED OCT 29 2014

.SYNOPSIS...
ISSUED AT 407 PM EDT WED OCT 29 2014

LOW PRESSURE LIFTING INTO QUEBEC TODAY WILL DRAG A WEAK COLD FRONT
THROUGH THE REGION...DELIVERING ANOTHER ROUND OF COOLER TEMPERATURES
ALONG WITH PERIODIC LAKE EFFECT RAIN SHOWERS. THOSE WILL END TONIGHT
INTO EARLY THURSDAY AS HIGH PRESSURE BRIEFLY ARRIVES. A STRONG COLD
FRONT WILL QUICKLY DROP THROUGH THE AREA THURSDAY NIGHT INTO EARLY
FRIDAY...USHERING IN VERY WINDY AND COLD CONDITIONS FOR HALLOWEEN...
AS WELL AS A PERIOD OF RAIN CHANGING TO SNOW FOR MANY AREAS. DRY BUT
CHILLY WEATHER IS EXPECTED HEADING INTO THE WEEKEND...WITH OUR NEXT
CHANCE FOR RAIN HOLDING OFF UNTIL EARLY NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 407 PM EDT WED OCT 29 2014

TONIGHT...THE UPPER LEVEL TROUGH THAT HAS BROUGHT SHOWERS TO THE
REGION SINCE LAST NIGHT PUSHES OFF TO OUR EAST THIS EVENING LEADING
TO A NEARLY ZONAL FLOW ALOFT TO DEVELOP BY OVERNIGHT. IN
ADDITION...DRIER AIR ADVECTS IN FROM THE NORTH WITH 1000-500 MB RH
DROPPING FROM NEARLY 80 PERCENT AT THE HOUR OF THIS WRITING TO ABOUT
55 PERCENT OVERNIGHT. HOWEVER...OVER LAKE INSTABILITY REMAINS
MARGINALLY UNSTABLE ENOUGH TO SUPPORT LIGHT LAKE EFFECT (LAKE/850 MB
DELTA T`S OF ABOUT +13 OR +14). THE DRIER AIR ALONG WITH SOME
SUBSIDENCE BETWEEN THE DEPARTING SYSTEM AND AN UPSTREAM SYSTEM DUE
IN ON THURSDAY SHOULD EVENTUALLY WIN OUT. THIS COMBINATION IS
EXPECTED TO RESULT IN DIMINISHING LAKE EFFECT RAIN SHOWERS LATER
THIS AFTERNOON...LEAVING ONLY LINGERING CHANCES FOR SHOWERS ACROSS
NORTHWEST FLOW FAVORED LOCALS LATER TONIGHT. A FEW WET SNOWFLAKES
MIXING IN WITH THE RAIN CAN NOT BE RULED OUT ACROSS EASTERN UPPER AS
THE MELTING LAYER SHRINKS TO ABOUT 1200 FEET AGL OR SO. AM A BIT
CONCERNED ABOUT LOW TEMPERATURES...WITH SATELLITE IMAGERY INDICATING
CLOUDS LOOKING RATHER CELLULAR. SO IF CLOUDS ARE ABLE TO PARTIALLY
CLEAR AND COMBINE WITH DIMINISHING WINDS...LOWS COULD EASILY FALL
OFF INTO THE MIDDLE AND UPPER 20S INLAND. THEREFORE...HAVE CUT
FORECAST LOWS/MODEL GUIDANCE BY A FEW DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 407 PM EDT WED OCT 29 2014

...RAW LOOKING HALLOWEEN ON TAP WITH WIND AND RAIN/SNOW...

HIGH IMPACT WEATHER POTENTIAL: FIRST ACCUMULATING SNOWFALL OF THE
SEASON EXPECTED THURSDAY NIGHT INTO FRIDAY.  STRONG NORTH/NORTHEAST
WINDS DURING THAT SAME TIME FRAME...40+MPH GUSTS EXPECTED ALONG
EXPOSED SHORELINE AREAS.

PATTERN SYNOPSIS/FORECAST: PROGRESSIVE UPPER LEVEL PATTERN ACROSS
NORTH AMERICA AND ADJACENT OCEANS...PART OF A FIVE WAVE HEMISPHERIC
PATTERN.  LARGER SCALE TROUGHING MOVING THROUGH THE GREAT
LAKES/MIDWEST TODAY.  SOME FLAT RIDGING ACROSS THE WESTERN HALF OF
THE CONUS THROUGH WHICH THE REMNANTS OF FORMER PACIFIC TROPICAL
CYCLONE "ANA" IS MOVING THROUGH (OVER MONTANA/WYOMING)...WITH
ANOTHER BETTER DEFINED SHORT WAVE TROUGH OVER THE HIGH LATITUDES OF
CENTRAL CANADA.  ANOTHER STRONG LARGER SCALE TROUGH WAS OVER THE
EASTERN PACIFIC.  SURFACE ANALYSIS SHOWS 991MB SURFACE LOW WRAPPED
UP EAST OF JAMES BAY WITH A COLD FRONT EXTENDING DOWN THE SPINE OF
THE APPALACHIANS.  HIGH PRESSURE ENCOMPASSED THE PLAINS/MIDWEST AND
CENTRAL CANADA.

THE EARLIER MENTIONED PAIR OF UPSTREAM SHORT WAVE TROUGHS WILL COME
TOGETHER TO CARVE OUT A STRONG TROUGH HEADING INTO HALLOWEEN FRIDAY
ACROSS THE EASTERN THIRD OF NORTH AMERICA.  THIS TROUGH WILL
EVENTUALLY SWING EAST TOWARD THE EAST COAST THIS WEEKEND...BRINGING
STRONG NORTHWEST FLOW ALOFT (AND COLD TEMPERATURES) TO MICHIGAN
BEFORE SHORT WAVE RIDGING PROVIDES A REPRIEVE EARLY NEXT WEEK.
IN THE NEAR TERM...WILL BE WATCHING TROUGH DEVELOPMENT OVER THE NEXT
48 HOURS WITH SURFACE PRESSURES FALLING THURSDAY AFTERNOON/NIGHT
ACROSS LOWER MICHIGAN.  RESULT WILL BE A STRONG PRESSURE GRADIENT
ACROSS THE FORECAST AREA THURSDAY NIGHT/FRIDAY BETWEEN DEVELOPING
LOW PRESSURE OVER THE REGION AND SURFACE HIGH OVER THE MIDWEST.
SURFACE HIGH WILL THEN NUDGE ITS WAY INTO THE UPPER LAKES/
MISSISSIPPI VALLEY ON SATURDAY.

PRIMARY FORECAST CONCERNS (NEAR TERM): IMPACTS OF DEVELOPING
HALLOWEEN SYSTEM THE OBVIOUS MAJOR CONCERN...PRECIPITATION
(EVOLUTION AND TYPE)/WINDS AND TRICK-OR-TREATING CONDITIONS
(PROBABLY NOT THE BEST).  INITIALLY WILL NEED TO DEAL WITH MORE
SYNOPTICALLY DRIVEN PRECIPITATION ON THURSDAY.

NEAR TERM (THURSDAY/FRIDAY): WILL BE A RELATIVE "CALM BEFORE THE
STORM" ON THURSDAY WITH A RELATIVELY FLAT PRESSURE GRADIENT ACROSS
THE UPPER LAKES.  SHORT WAVE REMNANTS OF "ANA" EXPECTED TO DIG
SOUTHEAST ACROSS THE MID MISSISSIPPI VALLEY...WITH A TRAILING SHORT
WAVE COMING OUT OF NORTHWEST ONTARIO.  BUT ENOUGH HEIGHT FALLS AND
TROUGHING BETWEEN THESE FEATURES TO SUPPORT AN AREA OF SHOWERS
SPREADING IN FROM THE NORTHWEST LATER THURSDAY MORNING INTO THE
AFTERNOON...WITH SOME ASSISTANCE FROM RESIDUAL LAKE PROCESSES (WHICH
MAY STILL RESULT IN SOME SPOTTY LAKE INDUCED RADAR RETURNS ACROSS
NORTHWEST LOWER/NORTHWEST CHIPPEWA COUNTY TO START THE DAY).
WIDESPREAD PRECIPITATION EXPECTED THURSDAY NIGHT WITH STRONGEST
HEIGHT FALLS/QG SUPPORT OVERSPREADING THE FORECAST AREA...AND AS
SURFACE LOW STARTS TO DEEPEN OVER LOWER MICHIGAN AN INCREASING
NORTHERLY WIND COMPONENT WILL START TO PULL IN COLDER AIR.  SO
PRECIPITATION TYPE WILL BE A CONCERN OVER EASTERN UPPER...WHERE A
CHANGEOVER TO SNOW IS MOST LIKELY DURING THE LATE EVENING AND
OVERNIGHT HOURS..AND CHANGEOVER SHOULD OCCUR EARLY ENOUGH TO MAKE IT
WORTH A MENTIONING AN INCH OR SO OF SNOW ACCUMULATION OVERNIGHT.
PRECIPITATION MAY START TO TRANSITION OVER TOWARD SNOW ACROSS
NORTHWEST LOWER EARLY FRIDAY MORNING...ESPECIALLY ACROSS THE
INTERIOR HIGHER TERRAIN.  SPEAKING OF RAMPING UP WINDS...SHOULD SEE
AN INCREASE IN WIND SPEEDS DURING THE PRE-DAWN HOURS OF FRIDAY
ACROSS EASTERN UPPER AND NORTH/WEST FACING SHORELINE AREAS.  WIND
GUSTS OVER 30 MPH EXPECTED INITIALLY...POSSIBLY OVER 40MPH ALONG THE
NORTHWEST LOWER LAKESHORE.

PRECIPITATION WILL CONTINUE FRIDAY AS CORE OF THE MAIN SHORT WAVE
TROUGH DIGS SOUTHEAST INTO THE OHIO VALLEY...WITH SYNOPTIC
PRECIPITATION ROTATING SOUTHEAST ALONG WITH IT.  LAKE ENHANCEMENT
EXPECTED WITHIN NORTH/NORTHEAST BOUNDARY LAYER FLOW OFF LAKES
MICHIGAN/HURON...WITH HIGHEST QPF FRIDAY EXPECTED OVER NORTHEAST
LOWER AS A RESULT.  PRECIPITATION ACROSS EASTERN UPPER EXPECTED TO
TAPER OFF BY AFTERNOON WITH A MOSTLY UNFAVORABLE TRAJECTORY FOR
PRECIPITATION OFF LAKE SUPERIOR.  LOW LEVEL COLD ADVECTION EXPECTED
TO TRANSITION PRECIPITATION OVER TO MORE SNOW AS THE DAY PROGRESSES
ACROSS NORTHERN LOWER MICHIGAN (PERHAPS STILL RAIN OR MIXY CLOSER TO
THE LAKES)...AND THINK AN INCH OR TWO OF ACCUMULATION INLAND IS
REASONABLE (AN INCH OR LESS EASTERN UPPER WHERE PRECIPITATION
EXPECTED TO END SOONER).  GUSTY NORTH WINDS COMBINED WITH
TEMPERATURES IN THE 30S WILL MAKE FOR A PRETTY RAW DAY...EVEN WITH
SOME AFTERNOON SUN ACROSS EASTERN UPPER.  WIND GUSTS 25-35 MPH
EXPECTED MOST AREAS...40-50MPH POSSIBLE NEAR THE NORTHWEST LOWER
SHORELINE WHICH COULD NECESSITATE A WIND ADVISORY STARTING FRIDAY
MORNING. SO NOT A PRETTY LOOKING TRICK-OR-TREAT PERIOD EXPECTED.  BY
FRIDAY NIGHT...PRECIPITATION WILL TRANSITION TO LAKE CONVECTION WITH
NORTH/NORTHEAST WINDS OFF LAKE HURON/MICHIGAN.

MEDIUM RANGE (SATURDAY/SUNDAY/MONDAY): WHILE STORMINESS IMPACTS THE
EAST COAST...STRONG NORTHWEST FLOW ALOFT WILL PERSIST ACROSS
MICHIGAN BETWEEN THE EASTERN STORM AND A SHORT WAVE RIDGING SPANNING
THE NATION`S MIDSECTION.  THIS RIDGE IS EXPECTED TO BUILD INTO THE
UPPER LAKES IN THE MONDAY TIME FRAME.  BUT DOES LOOK LIKE THINGS
WILL TREND QUIETER FOR THE WEEKEND...WITH TEMPERATURES STARTING TO
MODERATE AS HEIGHTS RISE.

OUTLOOK (TUESDAY/WEDNESDAY): SHORT WAVE TROUGH PASSAGE IN THE
TUESDAY TIME FRAME WILL BRING THE NEXT CHANCE FOR SHOWERS.  WILL
START WEDNESDAY DRY BUT UNCERTAINTY ABOUNDS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 148 PM EDT WED OCT 29 2014

SYNOPTICALLY DRIVEN MOISTURE IS STRIPPING OUT AT THE MOMENT AS
STORM SYSTEM RACES OFF TO THE NORTHEAST. STILL MARGINAL LAKE
EFFECT CONDITIONS THROUGH THIS EVENING POSSIBLY LEADING TO A FEW
SHOWERS. DRIER AIR THEN LOOKS TO ADVECT IN OVERNIGHT INTO THURSDAY
MORNING YIELDING A BREAK IN THE ACTION OUT AHEAD OF ANOTHER SYSTEM
LATER THURSDAY INTO THURSDAY NIGHT. CIGS ARE EXPECTED TO BE JUST
ABOVE MVFR THROUGH THE TAF PERIOD...THROUGH TEMPORARY IFR CIGS ARE
POSSIBLE AT TIMES...MAINLY AT TVC AND MBL. NORTHWEST WINDS WILL
DIMINISH LATER TODAY THEN BECOME LIGHT AND VARIABLE TONIGHT WITH
LIGHT WEST SOUTHWEST WINDS DEVELOPING THURSDAY.

&&

.MARINE...
ISSUED AT 407 PM EDT WED OCT 29 2014

WILL SEE WINDS RAMP UP THURSDAY NIGHT INTO FRIDAY AS LOW PRESSURE
STRENGTHENS OVER LOWER MICHIGAN.  STRENGTH OF THE SURFACE LOW NOT
EXPECTED TO BE SIGNIFICANT...BUT THE GRADIENT THAT SETS UP BETWEEN
THE LOW AND HIGH PRESSURE OVER THE MIDWEST WILL BE SIGNIFICANT AND
THAT WILL DRIVE WIND SPEEDS UPWARD ESPECIALLY WITH A DECREASE IN
OVER WATER STABILITY AND A FAVORABLE ISALLOBARIC GRADIENT.  GALE
FORCE WINDS EXPECTED WITHIN MOST LAKE MICHIGAN/LAKE HURON NEARSHORE
ZONES...SO CURRENT GALE WARNINGS/WATCHES WILL REMAIN INTACT (AND
WILL NEED SMALL CRAFT ADVISORIES ELSEWHERE).

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT FOR
     LHZ348-349.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LHZ347-348.
LM...GALE WARNING FROM 5 AM TO 11 PM EDT FRIDAY FOR LMZ323-342-
     344>346.
LS...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LSZ321.

&&

$$

SYNOPSIS...KB
SHORT TERM...AS
LONG TERM...JPB
AVIATION...AS
MARINE...JPB






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