Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 261410
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1010 AM EDT TUE AUG 26 2014

.SYNOPSIS...
ISSUED AT 258 AM EDT TUE AUG 26 2014

A COLD FRONT WILL PRESS THROUGH NORTHERN MICHIGAN AROUND DAYBREAK
AND THROUGH THIS MORNING. COOLER AND LESS HUMID AIR WILL GRADUALLY
REPLACE THE RECENT WARM AND HUMID AIR FROM THE LAST SEVERAL DAYS.
HIGH PRESSURE WILL SETTLE IN FOR WEDNESDAY AND THURSDAY WITH THE
NEXT POSSIBLE CHANCE FOR SHOWERS AND STORMS THURSDAY NIGHT THROUGH
THE UPCOMING WEEKEND.

&&

.UPDATE...
ISSUED AT 1008 AM EDT TUE AUG 26 2014

WEAK COLD FRONT HAS NOW CLEARED ALL OF NORTHERN LOWER
MICHIGAN. POST-FRONTAL CAA LIMITED AT BEST...BUT STILL ENOUGH
UNDERCUTTING MOIST BOUNDARY LAYER TO CAUSE WIDESPREAD STRATUS AND
PATCHY DRIZZLE...ESPECIALLY ACROSS THE HIGHLANDS OF NORTHERN LOWER
MICHIGAN. STILL EXPECT (OK...HOPE) ENOUGH MIXING THROUGH LATER
THIS MORNING AND AFTERNOON TO LEAD TO INCREASING AMOUNTS OF
SUNSHINE. FORECAST CHANGES THIS MORNING DRIVEN BY
ABOVE...INCREASING CLOUDS AND INTRODUCING DRIZZLE MENTION UNTIL
NOON. TEMPERATURE TRENDS WILL BE WATCHED...ALTHOUGH WOULD EXPECT
INCREASING SUN TO MAKE QUICK WORK OF WHAT HAS BEEN A SLOWER THAN
ANTICIPATED DIURNAL RESPONSE.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 111 AM EDT TUE AUG 26 2014

...BECOMING COOLER AND LESS HUMID...

IMPACTS: NONE.

CURRENT WEATHER AND SYNOPTIC PATTERN:

A BROAD SHALLOW UPPER TROUGH IS STRETCHED OUT FROM ONTARIO THROUGH
THE ARROWHEAD...WITH MAIN VORT MAX/LOW-UPPER JET FORCING ALL LIFTING
WELL NORTH AND EAST OF NRN MICHIGAN. WHILE THE EARLIER SHORTWAVE AND
SFC TROUGH THAT BROUGHT THE BAND OF SHOWERS AND STORMS YESTERDAY HAS
LONG SINCE LEFT THE REGION...THERE ARE A COUPLE OF WAVES NOTICEABLE
ON WV IMAGERY STILL UPSTREAM...ALONG/WEST OF A PRETTY DISTINCT COLD
FRONT DRAPED FROM CENTRAL UPPER MICHIGAN BACK THROUGH IOWA. LOW
LEVEL MOISTURE REMAINED POOLED ALONG THIS FRONT AND THE WEAKER
SHORTWAVE ACTION HAS RESULTED IN SLIGHTLY DEEPER MOISTURE AND WEAK
DEEP LAYER -DIVQ. THIS HAS SUBSEQUENTLY LED TO A FEW SHOWERS ACROSS
NRN IOWA. OVER NRN MICHIGAN...MOISTURE HAS STRIPPED OUT ALOFT PER
00Z APX SOUNDING...WITH SOME WARMING ALOFT 550-400MB. COOLING AT
700MB AND WARMING IN THE LOW LAYERS THOUGH HAS LEFT SOME LOWER LEVEL
ELEVATED INSTABILITY...WITH MUCAPES STILL AROUND OR JUST ABOVE
1000J/KG. THIS INSTABILITY IS DIMINISHING...AS MUCH DRIER AIR (SEEN
ON THE GRB 00Z SOUNDING)...IS SETTLING IN AS OF THIS DISCUSSION.
AREA VAD WIND PROFILES DO SUBSTANTIATE THIS...WITH A MARKED VEERING
OF THE H8 FLOW TO OUT OF THE NW.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

THE AFOREMENTIONED WEAKER VORTICITY MAXIMA WILL ROLL THROUGH
OVERNIGHT...ALONG WITH THE SFC COLD FRONT...WITH DRIVING WESTERLY
FLOW ALOFT. A NARROW CORRIDOR OF DEEPER MOISTURE AND DECAYING DEEP
LAYER -DIVQ IS EXPECTED AS THE VORTICITY SHEARS OUT WITH TIME. CAN
DEFINITELY NOT THROW OUT THE CHANCE FOR SEEING ISOLATED RAIN SHOWERS
WITH LAPSE RATES IN THE 6-6.5C/KM RANGE...BUT MOST FOLKS WILL ONLY
CONTINUE TO FEEL A VERY WARM AND MUGGY AIR MASS WITH NO RAIN THROUGH
THE NIGHT. SFC/BL MOISTURE WILL DROP BEHIND THE FRONT IN EASTERN
UPPER BY SUNRISE...AND THEN ACROSS THE REMAINDER OF NRN MICHIGAN
THROUGH THE DAY. DEEPER DRIER AIR IS SET TO SETTLE IN FOR THE DAY
AND INTO THE EVENING. THE LOW LEVEL COOLING WITH REMNANT WARMTH
ALOFT WILL RESULT IN FAVORABLE CAPPING FOR NO CHANCE OF DIURNAL
SHOWER DEVELOPMENT.

TROUGHING ACROSS WESTERN CANADA AND THE PAC NW WITH MAIN SHORTWAVE
ENERGY CURRENTLY DROPPING INTO CENTRAL CANADA...DOES ROLL THROUGH
LATE TONIGHT. THE LOW LEVEL COOLING AND DRIER AIR NEVER MOISTENS
WITH THE ARRIVAL OF THIS WAVE...BUT WE WILL HAVE THICKENING MID AND
UPPER LEVEL MOISTURE. THIS NOT UNCOMMON AT ALL WITH INCOMING SFC
HIGH PRESSURE. DESPITE UPPER TROUGHING BECOMING MORE DEFINED BY LATE
TONIGHT...DO NOT FORESEE ANY PRECIPITATION FALLING OUTSIDE OF SOME
POSSIBLE PATCHY SPRINKLES. THIS NOT WORTHY OF A MENTION IN THE
FORECAST ATTM.

HIGHS TODAY RANGING FROM THE UPPER AROUND 70F IN EASTERN
UPPER...WITH THE LOWER HALF OF THE 80S ACROSS DOWNSLOPING NE LOWER.
LOWS TONIGHT WILL NOT BE AS WARM/MUGGY...MAINLY IN THE LOWER HALF OF
THE 50S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 258 AM EDT TUE AUG 26 2014

OVERVIEW...THE CURRENT JET STREAM IS LOOKING MUCH MORE SUMMER LIKE
WITH THE FLATTENED 500 MB FLOW RUNNING CLOSER TO THE CANADIAN BORDER
THROUGH MOST OF THE NEXT 7 DAYS. THE ONLY THINGS WILL BE TO WATCH
THE INDIVIDUAL SHORTWAVES RUNNING THROUGH THE FLOW, AND THE 500 MB
LOW THAT MOVES THROUGH THE CENTER OF THE COUNTRY, AFFECTING THE
UPPER GREAT LAKES DURING THE WEEKEND. SO THE FORECAST WILL LOOK LIKE
THIS...

(8/27)WEDNESDAY/WEDNESDAY NIGHT...THE MODELS HAS THE 500 MB
SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES WITH THE SFC
HIGH OVER THE REGION. THE ECMWF (12Z) HAS SOME PRECIPITATION, BUT
WITH THE 850 MB RH AT <50%, THINK THAT IT IS OVERDOING THE RAIN. THE
GFS HAS RELATIVELY NOTHING AND EVEN MORE DRIER AIR. SO WILL ERR ON
THE SIDE OF BEING DRY. BY THE AFTERNOON, THE MODELS ARE ALL DRY AS
500 MB WAVE IS THROUGH AND THE <20% RH 700-500 MB LAYER AIR HAS
TAKEN OVER CONTROL OF THE FORECAST AREA. THE HIGH REMAINS IN CONTROL
THROUGH THE NIGHT. SO DRY WEATHER OVERNIGHT AS WELL. THE ONE THING
TO WATCH OUT FOR IS THE RETURN FLOW. IF IT ESTABLISHES LIKE THE GFS
IDEA, THEN...

(8/28)THURSDAY...THERE COULD BE SHOWER IN NW LOWER, MAINLY NEAR FKS
AND MBL. THE 00Z GFS HAS BACKED OFF THE RAIN SO THAT IT DOESN`T SHOW
UP UNTIL LATE AFTERNOON/EARLY EVENING. THE 12Z ECMWF IS STILL DRY
THROUGH THE DAY. AM INCLINED TO HEDGE TOWARD THE ECMWF BASED ON THE
IDEA THAT THE GFS IS RETREATING TOWARD THE ECMWF SOLUTION.
OVERNIGHT, THE MODELS ARE INSISTENT, HOWEVER, THAT RAIN MOVES INTO
THE REGION. IT`S A CLOSE CALL AS TO WHETHER THERE WILL BE THUNDER AT
THIS POINT. FOLLOWING MY LINE OF THINKING WITH THE ECMWF OVER THE
GFS, LOOKING AT THE K- AND SHOWALTER INDICES, THE ECMWF WOULD SAY
THAT THERE IS NO THUNDER, WHILE THE GFS WOULD SAY THAT THERE IS A
SMALL CHANCE TOWARD DAY BREAK. SO WILL CONTINUE TO KEEP THE THUNDER
OUT.

EXTENDED (FRIDAY THROUGH MONDAY)...(8/29)FRIDAY...THERE COULD BE
THUNDER, BASED ON THE SHOWALTER INDEX, AS THE WARM FRONT MOVES TO
ABOUT M-72. WILL CONTINUE TO LEAVE THE THUNDER OUT FOR NOW, BUT
WOULD LIKE TO SEE SOME BETTER MODEL CONSENSUS BEFORE FLIPPING THE
FORECAST. (8/30)SATURDAY...WILL KEEP THE CHANCE OF THUNDER AS THE
SHOWALTER INDEX/WARM FRONT CONTINUES SET UP OVER N LOWER.
(8/31)SUNDAY...IT LOOKS LIKE WE STAY ON THE NORTH SIDE OF THE SFC
LOW WITH THE 500 MB SHORTWAVE TROUGH PUSHING INTO TH E UPPER GREAT
LAKES. SO WILL ADD THE CHANCE OF SHOWERS TO THE DAY AND CONTINUE
THEM INTO THE NIGHT. (9/1)LABOR DAY...THE CHANCES OF RAIN LOOK TO BE
GETTING DOWNPLAYED BY THE MODELS AT THIS POINT. IT LOOKS LIKE
THERE`S A DRY SLOT THAT COULD LAST THE DAY OVER THE FORECAST AREA AT
THE 700-500 MB LAYER, AND RIDGING AT 500 MB SO COULD SEE HOW THIS
DAY IS DRY. THE GOING FORECAST WAS A CHANCE OF RAIN. WILL LEAVE THAT
FOR NOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 648 AM EDT TUE AUG 26 2014

A COLD FRONT IS CROSSING NRN MICHIGAN EARLY THIS MORNING WITH
SHALLOW COOL AIR WORKING WITH BL MOISTURE...RESULTING IN A PERIOD
OF MVFR CIGS. THIS WILL LIFT INTO A BKN VFR LAYER OF TRAPPED
FLAT CUMULUS UNDERNEATH AND INVERSION. SKIES WILL GRADUALLY
INCREASE IN SUN THROUGH THE DAY. LESS PERIOD OF CLOUDS AT MBL/TVC.

ONLY SOME SCATTERED HIGH CLOUD IN THE EVENING BEFORE THICKENING
OVERNIGHT.

WINDS WILL BE OUT OF THE WNW TODAY WITH SOME GUSTS TO 15 KNOTS
THIS AFTERNOON.


&&

.MARINE...
ISSUED AT 103 AM EDT TUE AUG 26 2014

A COLD FRONT WILL PASS THROUGH NRN MICHIGAN THIS MORNING WITH SOME
PATCHY GUSTY SW FLOW IN STABLE OVERLAKE CONDITIONS AHEAD OF THIS
FRONT...TURNING WNW AND REMAINING UNDER ADVISORY CRITERIA. HIGH
PRESSURE THEN BEGINS TO SETTLE IN FOR THE NIGHT AND HOLDS FOR
WEDNESDAY INTO THURSDAY. MAYBE A CHANCE FOR SHOWERS STARTING
THURSDAY NIGHT...AS A DISTURBANCE ALOFT AND SFC LOW/WARM FRONT NEARS
THE NEARSHORE WATERS OVER LAKE MICHIGAN...BUT NO FORESEEABLE
ADVISORY CRITERIA THROUGH THIS WORK WEEK.


&&

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

&&

$$

UPDATE...MSB
SYNOPSIS...SMD
SHORT TERM...SMD
LONG TERM...JL
AVIATION...SMD
MARINE...SMD





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