Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 312324
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
724 PM EDT FRI JUL 31 2015

.UPDATE...
ISSUED AT 724 PM EDT FRI JUL 31 2015

HAD BOOSTED POPS HIGHER INT HE EARLY EVENING HOURS...AS COVERAGE
WAS A LITTLE BETTER THAN PLANNED. ACTIVITY IS TAKING ON A MORE
CLASSIC LOOK...WITH SHADOWS FROM BOTH LAKES MI AND SUPERIOR.
HOWEVER...SOME ACTIVITY FROM WI HAS CROSSED LAKE MI INTO NW LOWER
NEAR FRANKFORT AND MBL (MUCH LIKE LAST NIGHT). THERE HAS BEEN A
DOWNWARD TREND IN COVERAGE OVER THE LAST 30MIN OR SO...AND THAT
TREND WILL CONTINUE THRU THE EVENING.

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 307 PM EDT FRI JUL 31 2015

IMPACT WEATHER: ISOLATED NON SEVERE STORM CHANCES AND ELEVATED
FIRE DANGER INTO THE EVENING.

SYNOPTIC PATTERN/OBSERVATIONS/EVOLUTION:

AFTERNOON ANALYSIS...DEEP LOW PRESSURE STILL SWIRLING OVER HUDSON
BAY WITH SEVERAL SHORTWAVE/VORTICITY MAXIMA AND ASSOCIATED SFC
TROUGHS ROTATING AROUND IT`S SRN FLANK. ONE SFC TROUGH WAS CROSSING
NRN LOWER AS OF 2 PM. DEW POINTS NEVER MIXED OUT AND TEMPERATURES
WARMED A COUPLE OF DEGREES MORE THAN EXPECTED. THIS...COMBINED WITH
A STEEP LAPSE RATE GRADIENT ALOFT...WERE JUST ENOUGH TO SPARK OFF
SCATTERED SHOWERS AND A FEW STORMS. THESE WILL CONTINUE TO MOVE ESE
IN THE MEAN WNW FLOW ALOFT...BEFORE THE TROUGH EXITS BY LATE
AFTERNOON LEAVING BEHIND MORE QUIET WEATHER. THAT ALL SAID...THERE
WAS OTHER ISOLATED SHOWER/POTENTIAL STORM ACTIVITY COMING FROM NE
WISCONSIN...DRIFTING TOWARD PORTIONS OF NW LOWER.

MOST ALL OF NRN MICHIGAN DID NOT GET ANY RAIN THUS FAR...AND THE
CONTINUATION OF GUSTY WESTERLY WINDS AND WARM TEMPERATURES WILL
CONTINUE TO RESULT IN ELEVATED FIRE DANGER INTO THE EARLY EVENING.

FEELING IS THAT AN ISOLATED SHOWER OR TWO CAN MAKE IT ACROSS NRN
LAKE MICHIGAN LATER THIS AFTERNOON AND EVENING...AS VISIBLE
SATELLITE LOOP SHOWS STILL BUILDING CUMULUS ACROSS SOUTH CENTRAL
UPPER MICHIGAN AND NE WISCONSIN. THIS IS AHEAD OF THE NEXT
APPROACHING SHORTWAVE AND POCKET OF STEEPER LAPSE RATES ALOFT...NOW
DRIVING THROUGH THE ARROWHEAD OF MN. THERE IS CERTAINLY MORE OF A
DIURNAL COMPONENT TO THE DEVELOPMENT OF THE SHOWERS AND STORMS...SO
ONCE AGAIN...GOTTA GO WITH THE IDEA OF SKIES OPENING UP MORE AS WE
HEAD THROUGH THE NIGHT...ESPECIALLY SINCE LATEST WV IMAGERY DOESN`T
SHOW ANOTHER DEFINED SHORTWAVE ON THE WAY. LOWS TONIGHT WILL BE VERY
SIMILAR TO LAST NIGHT...MIDDLE 50S TO LOWER 60S.

&&

.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 307 PM EDT FRI JUL 31 2015

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: A RATHER ENERGETIC...SHORT
WAVE FILLED FLOW REGIME IS EXPECTED THROUGH THE WEEKEND WITH
NORTHERN MICHIGAN LYING ON SOUTHERN PERIPHERY OF WELL DEVELOPED
HUDSON BAY UPPER LOW. WHILE THIS PATTERN AT TIMES MAY BE A WET ONE
FOR NORTHERN MICHIGAN...NOT SO MUCH AT LEAST INITIALLY WITH DEEP
MOISTURE AND INSTABILITY LACKING.  THAT MAY CHANGE SUNDAY INTO
SUNDAY NIGHT AS UPPER LOW SHIFTS SOUTHWARD WITH MORE FAVORABLE
MOISTURE/FORCING WORKING INTO NORTHERN MICHIGAN.

PRIMARY FORECAST CONCERNS/CHALLENGES: SCATTERED SHOWER/TSTM
POTENTIAL FOR THE FIRST HALF OF THE WEEKEND...AND POSSIBILITY OF
BETTER SHOWER/TSTM CHANCES SUNDAY AND SUNDAY NIGHT.

DETAILS: ADDITIONAL SHORTWAVE ENERGY BUT LESS THAN IMPRESSIVE
MOISTURE FIELDS ON SATURDAY. FACTOR IN VERY LITTLE SOIL MOISTURE
/ABNORMALLY DRY RECENTLY/ AND LESS THAN FAVORABLE KINEMATICS WITH
UPPER JET MAINLY OVERHEAD...AND IT IS DIFFICULT TO GET EXCITED ABOUT
RAIN CHANCES.  BEST OPPORTUNITY FOR PRECIPITATION ON SATURDAY
APPEARS TO BE OVER EASTERN UPPER AND PARTS OF NORTHEAST LOWER...WITH
HINTS OF BETTER LOW LEVEL CONVERGENCE OVERLAID ON BROAD WESTERLY
GRADIENT FLOW.  THIS MAY VERY WELL BE SUFFICIENT TO KICK OFF A FEW
SHOWERS AND POSSIBLY A RUMBLE OF THUNDER /ALTHOUGH MUCAPES LITTLE
MORE THAN 300-500 J/KG/.  FORECAST BECOMES "MUDDIER" SATURDAY
NIGHT AND SUNDAY AS MODELS DIVERGE ON STRENGTH/PLACEMENT OF
STRONGER UPSTREAM SHORTWAVE ENERGY AS MAIN HUDSON BAY UPPER LOW
GRADUALLY BEGINS TO SINK SOUTHWARD TOWARD THE NORTHERN LAKES.  THERE
LIKELY WILL BE A PERIOD OF "BETTER" RAIN CHANCES SOMETIME FROM LATE
SATURDAY NIGHT THROUGH SUNDAY NIGHT...BUT TIMING/PLACEMENT REMAINS
DIFFICULT GIVEN LACK OF MODEL CONSENSUS.  WILL TREND POPS TOWARD
HIGH CHANCE FOR SUNDAY AFTERNOON AND SUNDAY NIGHT...WHICH IS WHEN
MOST OF THE MODELS CLUSTER THE HIGHEST RAIN CHANCES WITH NEXT
SHORTWAVE/COLD FRONT.

A CLOUDIER AND COOLER PATTERN TO START THE WEEK ON MONDAY WITH COOL
AIR ALOFT LIKELY HELPING TO PRODUCE AT LEAST SOME SCATTERED
DIURNALLY DRIVEN SHOWERS WITH BROAD CYCLONIC FLOW ACROSS THE
NORTHERN LAKES.

&&

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI JUL 31 2015

AN UPPER LEVEL TROUGH CENTERED OVER HUDSON BAY WILL SLOWLY BEGIN TO
BREAK DOWN AND SHIFT EASTWARD THROUGHOUT THE FIRST HALF OF THE
PERIOD...BECOMING MORE ZONAL ACROSS THE MIDDLE OF THE CONUS BY THE
MIDDLE TO END OF NEXT WEEK. FOR MONDAY NIGHT THROUGH WEDNESDAY
...WITH A 90 KT UPPER LEVEL JET NOSING INTO THE GREAT LAKES AND
DECENT MID-LEVEL MOISTURE (H7 RELATIVE HUMIDITIES RANGING BETWEEN 75-
90%)...WOULDN`T BE TOO SHOCKED TO SEE A CLOUDIER SCENARIO VERIFY
WITH ANY WEAK RIPPLE IN NORTHWEST FLOW ABLE TO KICK OFF A FEW
SCATTERED SHOWERS AND/OR DRIZZLE. AT THIS POINT...HAVE HELD ON TO
OCCASIONAL LOW END CHANCE POPS ACROSS PARTS OF THE AREA. AS THE
UPPER LEVELS BECOME MORE ZONAL BY THE SECOND HALF OF THE
WEEK...THERE ARE HINTS FROM SEVERAL GLOBAL MODEL GUIDANCE MEMBERS
THAT WE SEE RETURN FLOW AND PERHAPS A MORE MOISTURE-RICH SYSTEM WORK
ITS WAY THROUGH THE CENTER OF THE COUNTRY.

MUCH COOLER TEMPERATURES THAN WE`VE SEEN RECENTLY ARE EXPECTED
THROUGHOUT THE EXTENDED PERIOD WITH HIGH TEMPERATURES TOPPING OUT A
FEW DEGREES ON EITHER SIDE OF 70 TUESDAY-FRIDAY...ROUGHLY 10 DEGREES
BELOW THE CLIMATOLOGICAL NORMAL OF 79-80 DEGREES FOR THE FIRST WEEK
OF AUGUST.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 724 PM EDT FRI JUL 31 2015

VFR.

UPPER LEVEL DISTURBANCES AND COOLER AIR ALOFT ARE COMBINING TO
PRODUCE INSTABILITY ACROSS THE REGION. THIS HAS RESULTED IN SOME
SHRA/ISOLATED TSRA DEVELOPMENT. THIS ACTIVITY WILL TEND TO WEAKEN
AS WE MOVE THRU THE EVENING HOURS. APN/MBL ARE THE MOST LIKELY
SPOTS TO SEE A FEW RAINDROPS THIS EVENING. SOMETHING SIMILAR WILL
HAPPEN AGAIN SATURDAY AFTERNOON...WITH APN AGAIN THE MOST LIKELY
TO SEE SHRA. ANY CIGS WILL REMAIN COMFORTABLY VFR...MOSTLY IN THE
6-10K FT RANGE.

WINDS WILL GO LIGHT THIS EVENING. A W TO NW BREEZE WILL OCCUR
AGAIN ON SATURDAY...THOUGH WEAKER THAN TODAY.

&&

.MARINE...
ISSUED AT 307 PM EDT FRI JUL 31 2015

THERE HAVE ONLY BEEN SOME BRIEF OFFSHORE GUSTS IN THE 20 TO 25 KNOT
RANGE INTO THE LAKE HURON NEARSHORE WATERS...OTHERWISE WINDS HAVE
HELD BELOW SMALL CRAFT ADVISORY THRESHOLDS. WIND SPEEDS ARE EXPECTED
TO REMAIN UNDER ADVISORY LEVELS OVER THE NEXT FEW DAYS...WHILE WIND
DIRECTIONS OSCILLATE BETWEEN SW AND NW. THIS IS DUE TO A SERIES
OF DISTURBANCES ALOFT...AND THEIR ASSOCIATED SFC TROUGHS CROSSING
THE GREAT LAKES. OVERLAKE STABILITY WILL BE SLOWLY DECREASING
HOWEVER...AND MAYBE SOME LOW END ADVISORIES GRADUALLY BECOME
POSSIBLE INTO NEXT WORK WEEK.

THROUGH EVENING...ISOLATED SHOWERS AND A POSSIBLE STORM WILL IMPACT
LAKES HURON AND MICHIGAN.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ345.

LM...NONE.
LS...NONE.
&&

$$

UPDATE...JAZ
NEAR TERM...SMD
SHORT TERM...KEYSOR
LONG TERM...GILLEN
AVIATION...JAZ
MARINE...SMD


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