Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 210445
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1245 AM EDT MON JUL 21 2014

.SYNOPSIS...
ISSUED AT 324 PM EDT SUN JUL 20 2014

A COLD FRONT OVER CENTRAL CANADA AND EXTENDING BACK ALONG THE
INTERNATIONAL BORDER OF NORTH DAKOTA AND MONTANA WILL BE SLOW TO
MOVE TOWARD THE GREAT LAKES REGION...ALLOWING SOUTHWEST WINDS AHEAD
OF THE FRONT TO DRAW WARMER AND MORE HUMID AIR UP INTO NORTHERN
MICHIGAN FOR THE EARLY PART OF THIS WEEK.  NEXT CHANCE FOR RAINFALL
WILL COME TUESDAY AS THE COLD FRONT STRETCHES EAST INTO THE UPPER
GREAT LAKES...WITH OUR QUICK WARM UP GIVING WAY TO COOLER AND LESS
HUMID CONDITIONS BY MIDWEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 324 PM EDT SUN JUL 20 2014

HIGH IMPACT WEATHER POTENTIAL:  NONE

OVERVIEW: FLAT RIDGE OVER THE NORTHERN TIER OF THE UNITED STATES
WITH WEAK TROFINESS STILL LINGERING ACROSS THE GREAT
LAKES/NORTHEAST.  A WEAK SHORTWAVE WILL SLIDE OVER THE RIDGE AND
ACROSS LAKE SUPERIOR...RESULTING IN A FEW MORE CLOUDS BUT LIKELY
CONTINUED DRY CONDITIONS.  OTHERWISE...JUST SOME PATCHES OF MID
CLOUDS MOVING ACROSS THE AREA.

TONIGHT: A FEW SPRINKLES/VERY LIGHT SHOWER POSSIBLE THROUGH EARLY
EVENING ALONG INLAND PENETRATING LAKE BREEZE BOUNDARIES NEAR LAKE
HURON...BUT WILL LEAVE OUT OF THE FORECAST GIVEN LOW PROBABILITY/LOW
COVERAGE.  DIURNAL CU WILL DISSIPATE THIS EVENING WITH LOSS OF
DAYTIME HEATING...LEAVING JUST SOME THIN MID/HIGH CLOUDS.    MID
LEVEL THETA-E RIDGE WILL WORK SLOWLY EASTWARD OVERNIGHT...KEEPING AT
LEAST SOME MID/HIGH LEVEL CLOUDINESS ACROSS NORTHERN MICHIGAN.  A
WEAK SHORTWAVE TROF WILL MOVE OUT OF SOUTHERN CANADA AND ACROSS LAKE
SUPERIOR OVERNIGHT. DRY LOW LEVELS AND MINIMAL FORCING SHOULD
PRECLUDE ANY PRECIPITATION FROM THIS FEATURE...WITH IT/S ONLY IMPACT
POSSIBLY BEING A BIT MORE CLOUD COVER ACROSS NORTHERN PORTIONS OF
THE AREA.  OTHERWISE...A QUIET AND MILD NIGHT ACROSS NORTHERN
MICHIGAN.  LOW TEMPERATURES IN THE MID 50S TO LOWER 60S.  A TOUCH OF
FOG POSSIBLE ONCE AGAIN OVER PORTIONS OF EASTERN UPPER/NORTHEAST
LOWER WHERE H10-H9 MOISTURE CONVERGENCE WILL BE MAXIMIZED WITH
CONTINUING LIGHT GRADIENT FLOW AND WEAK SURFACE DWPT ADVECTION. WILL
HAVE TO WATCH MARINE FOG OFF OF LAKE HURON /THUNDER BAY/...WHICH MAY
TRY TO DRIFT TOWARD THE LAKE HURON COAST WITH LIGHT SOUTH/SOUTHEAST
FLOW THIS EVENING.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 324 PM EDT SUN JUL 20 2014

...WARM AND HUMID CONDITIONS RETURN...BUT ONLY BRIEFLY...

HIGH IMPACT WEATHER POTENTIAL: LOW POTENTIAL FOR SEVERE WEATHER
TUESDAY AND TUESDAY NIGHT.

PATTERN SUMMARY AND FORECAST:  TROUGHING THAT HAS DOMINATED THE
PATTERN ACROSS EASTERN NOAM MUCH OF THE PAST WEEK IS FALLING APART
AS PACIFIC FLOW IS FLOODING ACROSS CANADA WITH LEAD SHORTWAVE
PUSHING INTO NORTHWESTERN ONTARIO KICKING ANY REMAINING EASTERN
TROUGHING INTO THE ATLANTIC. THUS...HEIGHTS ARE BUILDING
OVERHEAD...AND WILL CONTINUE TO DO SO AS MID LEVEL FLOW PATTERN
TAKES ON MORE OF A SOUTHWESTERLY DIRECTION AS ENERGY DROPS SOUTH
INTO THE GULF OF ALASKA.  THIS UPSTREAM AMPLIFICATION TO THE PATTERN
WILL EVENTUALLY HAVE MORE DOWNSTREAM CONSEQUENCES AS IT FORCES
LONGWAVE RIDGE DEVELOPMENT JUST ALONG/JUST EAST OF THE SPINE OF THE
ROCKIES WITH DOWNSTREAM TROUGH DEVELOPMENT JUST TO THE EAST OF OUR
LONGITUDE FOR THE MIDDLE/LATTER PORTIONS OF THIS WEEK.  THIS LATTER
PATTERN IS ONE WE WILL ALL RECOGNIZE AS IT HAS BEEN WITH US FOR MUCH
OF THE SUMMER (AND SPRING...AND WINTER).  LOOKING FORWARD TO THE END
OF THE COMING WORK WEEK AND INTO NEXT WEEKEND...THE WESTERN
TROUGHING PUSHES EAST...SERVING TO RELOAD THE TROUGH OVER EASTERN
NOAM.  THIS WILL GENERALLY MAINTAIN NORTHWEST FLOW ALOFT OUTSIDE OF
A BRIEF PERIOD /FRI?/ AS THE TROUGH TO OUR EAST RELOADS.

PATTERN IMPLICATIONS:  BUILDING HEIGHTS AND SOUTHWEST FLOW ALOFT
EARLY SUGGEST A PERIOD OF WARMER THAN NORMAL CONDITIONS.
HOWEVER...OVERALL TREND BACK TOWARDS EASTERN TROUGHING SUGGESTS
THAT BEYOND MONDAY-TUESDAY...TEMPERATURES SHOULD RETURN TO AT OR
BELOW SEASONAL NORMS FOR MUCH OF THE REMAINDER OF THE FORECAST
PERIOD.  AS FOR SENSIBLE WEATHER...THE TRANSITION FROM EARLY WARMTH
BACK TO NORMAL FOR THE SECOND HALF OF THE WEEK SHOULD BRING
SHOWER/THUNDERSTORM POTENTIAL.  WITH THE REMAINDER OF THE FORECAST
DOMINATED BY NORTHWEST FLOW...GENERALLY DRY CONDITIONS WOULD BE
EXPECTED...OUTSIDE OF LOWER SHOWER/THUNDERSTORM POTENTIAL WHEN THE
TROUGH RELOADS LATE IN THE PERIOD.

MODEL AGREEMENT/CONFIDENCE: LARGE SCALE PATTERN AGREEMENT IS RATHER
GOOD THROUGH THE FORECAST PERIOD...WITH ABOVE-AVERAGE CONFIDENCE IN
THE OVERALL EVOLUTION.  CONFIDENCE IS OF COURSE REDUCED WITH
PRECIPITATION/SEVERE WEATHER POTENTIAL TUESDAY GIVEN IT/S CONVECTIVE
NATURE.

MIDDLE RANGE /MONDAY THROUGH WEDNESDAY/:

WARMER THAN NORMAL TEMPERATURES FULLY ENVELOP THE REGION ON MONDAY
AS T8S BUILD THROUGH THE TEENS WITH HEIGHT RISES ALOFT AS WELL.
THESE VALUES REPRESENT +1SD ANOMALIES...SO CERTAINLY NOTHING
ABNORMAL.  MIXING HEIGHTS WILL COME DOWN SOME WITH RISING HEIGHTS
ALOFT...BUT WE SHOULD BE ABLE TO PRETTY MUCH MIX TO H8...SUGGESTING
SOMETHING CLOSE TO THE MID 80S.  WHILE MOISTURE RETURN WILL BE
ONGOING...RISING HEIGHTS AND NO FORCING FEATURES ALOFT SUGGEST WE
SHOULD REMAIN DRY THROUGH THE DAY.  CERTAINLY LOOKING FOR A WARMER
NIGHT MONDAY NIGHT AS THERMAL RIDGE FOLDS OVERHEAD...GRADIENT
TIGHTENS SOME /KEEPING ALL BUT NORTHEAST LOWER COUPLED/.  THIS
BREEZE SHOULD NEGATE SIGNIFICANT FOG POTENTIAL...BUT A HAZY TUESDAY
MORNING IS CERTAINLY PLAUSIBLE...WITH LOWS IN THE 60S.

GREATEST POTENTIAL FOR HIGH IMPACT WEATHER COMES AS WE REACH
TUESDAY.  THERE IS GENERAL AGREEMENT UPON MCS DEVELOPMENT OVER
MINNESOTA/WISCONSIN MONDAY NIGHT...WITH THE EVOLUTION OF THIS
FEATURE LIKELY THE CRITICAL ELEMENT DETERMINING OUR SENSIBLE WEATHER
FOR THE PERIOD.  RIGHT ENTRANCE REGION JET FORCING MOVES EAST ALONG
LAKE SUPERIOR/UPPER MICHIGAN THROUGH THE DAY...SUGGESTING A PLAUSIBLE
PATH OF REMNANT CONVECTION/MCV.  FURTHER SOUTH...ATTENTION TURNS TO
PRETTY ROBUST SURFACE COLD FRONT...WITH REASONABLE AGREEMENT THAT
THIS FEATURE REACHES WESTERN UPPER/EASTERN WISCONSIN TOWARDS
EVENING.  WIND FIELDS ALOFT ARE SUBSTANTIAL...WITH PRIMARY
LIMITING FACTOR BEING INSTABILITY WITH EVEN THE MOIST NAM KEEPING
AREAS SOUTH OF MCV SAFELY CAPPED TUESDAY /WITH AFTERNOON
REDEVELOPMENT MORE LIKELY SOUTH AND WEST OF LAKE MICHIGAN/...AND
THEN ONLY LIMITED INSTABILITY WITH FRONTAL PASSAGE TUESDAY NIGHT.

MUCH OF NORTHERN LOWER COULD REMAIN DRY TUESDAY...WITH LOW CHANCE
POPS STILL WARRANTED TOWARDS NW LOWER AND THE TIP OF THE MITT CLOSER
TO POTENTIAL MCV.  WILL EXPAND POPS TO ALL REGION TUESDAY NIGHT WITH
ROBUST FRONTAL PASSAGE.  CLEARLY...THIS IS A CONVECTIVE SCENARIO...
WITH CHANGES TO ABOVE EXPECTATIONS LIKELY.

FROM A SEVERE WEATHER PERSPECTIVE...THERE/S A CONDITIONAL SEVERE
THREAT GIVEN THE IMPRESSIVE WIND FIELDS...WITH THE THREAT NOT HIGHER
GIVEN LACKING INSTABILITY.  THIS IS IN COMPLETE AGREEMENT WITH SPC/S
DAY 3 SEE TEXT.

TEMPERATURES VERY DEPENDENT ON THE CONVECTIVE EVOLUTION MENTIONED
ABOVE...WITH T8S NEAR +18C WARM ENOUGH TO ALLOW 90 TO BE REACHED IF
WE CAN SEE ENOUGH SUN.  BEST CHANCES FOR THIS OVER N/NE LOWER AND
PREVIOUSLY INHERITED FORECAST CAPTURES THIS WELL.

SUBSTANTIAL CHANGE TO COOLER AIRMASS ON WEDNESDAY WITH T8S FALLING
BACK TOWARDS 10C UNDER NORTHERLY FLOW. DEPENDING ON FRONTAL TIMING
TUESDAY NIGHT...COULD SEE SOME REMNANT SHRA ACTIVITY EARLY...BUT
OTHERWISE A MUCH COOLER DAY WITH A SIGNIFICANTLY DRY AIRMASS
ARRIVING.  CONSENSUS GUIDANCE NUMBERS GENERALLY IN THE 70S LOOK
GOOD...WITH MORNING FRONTAL TIMING LIKELY TO PLAY A ROLE IN WHETHER
PORTIONS OF NE LOWER CAN WARM MORE THAN THIS.

LONG RANGE /THURSDAY THROUGH SUNDAY/:

CANADIAN HIGH PRESSURE IN COMPLETE CONTROL THURSDAY AND FRIDAY /AND
LIKELY EVEN SATURDAY/ WITH SEASONABLY COOL TEMPERATURES /HIGHS IN
THE LOW-MID 70S/ EXPECTED WITH T8S NEAR 8C ON THURSDAY AND 10C ON
FRIDAY. AN EARLY LOOK AT NEXT WEEKEND REVEALS ANOTHER ARRIVING
SHORTWAVE THAT WILL SERVE TO REINFORCE THE EASTERN TROUGH.
DEPENDING ON IT/S EXACT TIMING/LOCATION...A WARMER DAY WITH HIGHS
NEAR SEASONAL NORMS IS POSSIBLE...BUT THE MORE LIKELY SCENARIO GIVEN
CURRENT GUIDANCE CONSENSUS IS CONTINUED AT/BELOW NORMAL TEMPERATURES
WITH INCREASING CHANCES FOR SHOWERS /AN POSSIBLY THUNDERSTORMS/.
THIS LOOKS TO SETUP ANOTHER POTENTIALLY COOL PERIOD THE FOLLOWING
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1244 AM EDT MON JUL 21 2014

MAINLY VFR CONDITIONS WILL PERSIST AT ALL NRN LWR MICHIGAN TAF
SITES THRU MONDAY NIGHT AS HIGH PRESSURE SHIFTS EASTWARD AND
MID/HIGH CLOUDS CONTINUE TO DRIFT THRU THE REGION IN STRENGTHENING
S/SW LOW LEVEL FLOW. THE EXCEPTION WILL BE ACROSS PORTIONS OF NE
LWR MICHIGAN WHERE SOME MVFR FOG IS EXPECTED TO DEVELOP OVERNIGHT.
LLWS WILL IMPACT PLN OVERNIGHT AS LOW LEVELS DECOUPLE AND SW WINDS
JUST OFF THE DECK STRENGTHEN. LIGHT/VARIABLE SURFACE WINDS OVERNIGHT
WILL BECOME SW AROUND 10 KTS BY MID TO LATE MORNING.

&&

.MARINE...
ISSUED AT 324 PM EDT SUN JUL 20 2014

SUMMARY: THE MARINE WATERS REMAIN BETWEEN HIGH PRESSURE OVER NEW
ENGLAND AND LOW PRESSURE OVER THE CANADIAN PRAIRIES.  A COLD FRONT
ASSOCIATED WITH THIS LOW WILL MOVE TOWARDS THE GREAT LAKES THROUGH
TUESDAY WITH STRENGTHENING SOUTHWEST FLOW AHEAD OF IT.  THE FRONT
WILL CROSS THE REGION TUESDAY NIGHT...WITH HIGH PRESSURE BUILDING
INTO THE GREAT LAKES FOR THE SECOND HALF OF THE WEEK.

HEADLINES: CONDITIONS LOOK TO REMAIN BELOW SMALL CRAFT LEVELS
THROUGH TONIGHT BEFORE STRENGTHENING SOUTHWEST WINDS MAY WILL LIKELY
PRODUCE SOME MARGINAL SMALL CRAFT CONDITIONS ON MONDAY AND
TUESDAY...PARTICULARLY ACROSS LAKE MICHIGAN.  BY WEDNESDAY...
NORTHERLY WINDS BEHIND DEPARTING COLD FRONT MAY AGAIN BRING MARGINAL
SMALL CRAFTS TO ALL MARINE WATERS...WITH HEADLINE-FREE CONDITIONS
EXPECTED FOR THE SECOND HALF OF THE WEEK.

FOG:  ONGOING ALONG MUCH OF THE COASTLINE OF NORTHEAST LOWER...WITH
MARINE FOG LIKELY OVER LAKE HURON THROUGH TUESDAY/TUESDAY NIGHT AS
LLEVELS CONTINUE TO MOISTEN AHEAD OF ARRIVING COLD. EXPECT A SIMILAR
EVOLUTION OVER WHITEFISH BAY...WITH LIKELY LESS FOG AT LEAST THROUGH
MONDAY OVER LAKE MICHIGAN WITH BETTER LLEVEL MIXING.

THUNDERSTORMS: THUNDERSTORMS ARE POSSIBLE BEGINNING EARLY TUESDAY
AND CONTINUING THROUGH TUESDAY NIGHT.  THERE IS A LOW CHANCE OF A
SEVERE THUNDERSTORM PRIMARILY TUESDAY AFTERNOON.


&&

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

&&

$$

SYNOPSIS...TL
SHORT TERM...JK
LONG TERM...ARNOTT
AVIATION...MR
MARINE...ARNOTT






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