Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 291043
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
643 AM EDT TUE JUL 29 2014

.SYNOPSIS...
ISSUED AT 318 AM EDT TUE JUL 29 2014

SEVERAL WEAK UPPER LEVEL DISTURBANCES ROTATING ACROSS THE
REGION THIS WEEK WILL BRING PERIODIC CHANCES FOR SHOWERS AND A FEW
THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON HOURS. DESPITE A
SLOW MODERATION...TEMPERATURES WILL REMAIN BELOW NORMAL INTO THE
START OF THE WEEKEND.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 318 AM EDT TUE JUL 29 2014

...SCATTERED SHOWERS AND STORMS AND SMALL HAIL FOR SOME...

IMPACTS: LIGHTNING...SMALL HAIL...BUT NO SEVERE WEATHER EXPECTED.

CURRENT WEATHER AND SYNOPTIC PATTERN:

DEEP CLOSED UPPER LOW WAS SLOWLY RETROGRADING WESTWARD TOWARD JAMES
BAY...WITH SEVERAL VORTICITY MAXIMA ROTATING AROUND IT. ONE OF THESE
WAVES AND ASSOCIATED SFC TROUGH SEEN ON AREA OBS IN EASTERN UPPER.
THERE WERE A COUPLE OF SMALL RETURNS SEEN ON RADAR WITH THIS TROUGH
AS FAR SOUTH AS LEELANAU/BENZIE COUNTY AND JUST OFFSHORE. THE BETTER
COVERAGE AND INTENSITY SHOWERS/FEW THUNDERSTORMS WAS WELL WEST OF US
FROM THE ARROWHEAD OF MN DOWN INTO CENTRAL WISCONSIN AHEAD OF ONE
VORTICITY MAXIMA.  THIS IS NEARER THE STRONGER OVERALL FORCING...JET
DYNAMICS...STEEPER LAPSE RATES AND TOTAL PWAT. COVERAGE AND
THUNDERSTORM ACTIVITY WAS BETTER YESTERDAY AFTERNOON WITH THE
ASSISTANCE OF DAYTIME HEATING.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

UPPER LOW WILL ROTATE DRIFT OVER/JUST SOUTH OF JAMES BAY THROUGH
TONIGHT. AFOREMENTIONED SFC TROUGH DRIVES THROUGH NRN MICHIGAN NOW
INTO MID MORNING. VORT MAX LOOKS TO WEAKEN WITH TIME...WITH JUST A
SOME ISOLATED LIGHT SHOWERS MOVING ON THROUGH. ANOTHER MID LEVEL
TROUGH AXIS IS ANTICIPATED THIS AFTERNOON FROM NE WISCONSIN AND
POSSIBLE CLIPPING TVC BAY REGION. WE WILL ALSO SEE THE BETTER JET
FORCING ACROSS THIS AREA...ALONG WITH STEEPER LAPSE RATES TO 6.5C/KM
AND BETTER PWATS. IN THE MEANTIME...A CORRIDOR OF DRIER AIR (SEEN ON
LATEST IR IMAGERY NOSING INTO SRN ONTARIO) SWEEPS DOWN AND LAYS OUT
ACROSS EASTERN UPPER AND MAYBE A GOOD CHUNK OF NE LOWER. WHILE
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP ACROSS MAINLY THE GTV
BAY REGION...THE ACTIVITY WILL BE MORE LIMITED THE MORE E/NE OF
THERE. ACTUALLY BELIEVE SEEING NO PRECIPITATION ACROSS EASTERN UPPER
AND FAR NE LOWER IS A GOOD POSSIBILITY.

FREEZING LEVELS DOWN TO ~9500 FT SUGGEST KEEPING SMALL HAIL INTO THE
FORECAST PICTURE...BUT SEVERE WEATHER IS NOT TOO LIKELY. OVERALL
INSTABILITY ACROSS THE GTV BAY REGION MAY NEAR 1000 J/KG...WITH THE
BEST INSTABILITY ACROSS EASTERN WISCONSIN. THIS IS WHERE THERE WILL
BE THE BETTER CHANCE FOR SOMETHING SEVERE. PRIMARILY A LARGER HAIL
THREAT.

HIGHS STILL QUITE COOL FOR LATE JULY...UPPER 60S AND LOWER 70S. NOT
AS MUCH CLOUD COVER AROUND TONIGHT...RESULTING IN LOWS IN THE UPPER
40S TO LOWER 50S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 318 AM EDT TUE JUL 29 2014

...A SLOW MODERATING TREND...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: TROUGHING DOMINATES...AND
WILL CONTINUE TO DO SO RIGHT THROUGH THE REMAINDER OF THIS WEEK.
ASSOCIATED COLDEST TEMPERATURE ANOMALIES ARE A THING OF THE
PAST...HOWEVER...AND LOOK TO REMAIN JUST OFF TO OUR NORTHEAST
THROUGH THE DURATION. PER THE USUAL...SUCH TROUGHING IS OFTEN AN
UNSTABLE ONE IN THE HEART OF SUMMER...AND WILL NEED TO BE ON THE
LOOKOUT FOR PERIODIC MAINLY AFTERNOON AND EARLY EVENING SHOWER/STORM
DEVELOPMENT. DEEPEST MOISTURE AND GREATEST INSTABILITY IS WELL
REMOVED...SO NOT EXPECTING ANY TYPE OF SEVERE WEATHER THREAT OR
HEAVY RAIN. PATTERN ATTEMPTS DEAMPLIFICATION HEADING INTO THE
WEEKEND AND THE START OF NEXT WEEK. AGREE THAT IT SHOULD DO SO...BUT
HAVE A HUNCH AT LEAST A LOWER AMPLITUDE VERSION OF CURRENT PATTERN
WILL REMAIN GIVEN MAGNITUDE OF BLOCKING.

PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE AND CLOUD TRENDS
THROUGHOUT. ACCESSING MAINLY AFTERNOON AND EVENING SHOWER AND STORM
POTENTIAL FOR THE REMAINDER OF THIS WEEK.

DETAILS: JUST KINDA A "MESSY" WEATHER PATTERN HEADING THROUGH THIS
WEEK AS WEAK WAVES ROTATING AROUND PARENT TROUGHING INTERACT WITH
THE DAILY INSTABILITY CYCLE. OF COURSE...EXACT TIMING OF SUCH WAVES
A FRUITLESS ENDEAVOR JUST YET. THROW IN LAKE MICHIGAN AND SUPERIOR
LAKE SHADOWS...AND FIGURING SPATIAL AND TEMPORAL RESOLUTION OF
BETTER SHOWER CHANCES BECOMES A RATHER FORMIDABLE CHALLENGE. AT NO
POINT DOES INSTABILITY LOOK OVERWHELMING...WITH GENERAL COOL AIRMASS
AND RATHER LIMITED DEEP LAYER MOISTURE. H5 TEMPERATURES LOOK TO COOL
A TOUCH ON WEDNESDAY BEFORE MODERATING...AT LEAST HELPING THE
INSTABILITY CAUSE. SIMPLY FORCED TO KEEP THINGS GENERIC...WITH A
STRONG TREND TOWARD NORTHERN MICHIGAN SUMMER CONVECTION
CLIMATOLOGY...KEEPING AT LEAST SOME MENTION OF DAYTIME SHOWER
CHANCES THROUGH THE START OF THE WEEKEND. WILL PROBABLY REGRET
SAYING THIS...BUT AS A ROUGH FIRST GUESS IT APPEARS THE "BEST"
POTENTIAL FOR RAINS WILL BE BOTH FRIDAY AND SATURDAY AFTERNOON WHEN
WAVE TIMING APPEARS TO BE BEST COLLOCATED WITH PEAK OF AFTERNOON
INSTABILITY CYCLE. NOW...HAVING JUST SAID THAT...REALITY WILL LIKELY
BE NOWHERE NEAR WHAT CURRENT GUIDANCE IS SUGGESTING. EITHER WAY...AT
NO POINT DOES A WASHOUT APPEAR IN THE WORKS...WITH MORE OF A SHORT
DURATION SHOWER ENVIRONMENT AND LONG PERIODS OF NO RAIN AT ALL.

FORECAST TO END THE WEEKEND AND INTO THE START OF NEXT WEEK WILL BE
STRONGLY TRENDED TOWARD A GENERIC MODEL CONSENSUS BLEND APPROACH.
SUCH SAYS ADDITIONAL LOW END POPS ARE WARRANTED SUNDAY NIGHT AND
MONDAY AS WEAK WAVES TRAVERSE OVERHEAD IN GRADUALLY DEAMPLIFYING
FLOW. ITS A START...AND ONE THAT WILL NO DOUBT CHANGE IN THE COMING
DAYS.

AS MENTIONED EARLIER...TEMPERATURES WILL BE PAINFULLY SLOW TO
MODERATE AS AIRFLOW REMAINS LARGELY DIRECTED OUT OF CANADA. HIGH
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE DURATION...BUT AT
LEAST ATTEMPT TO GET CLOSER TO WHAT IS MORE REASONABLE FOR THIS TIME
OF YEAR BY THE END OF THE PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 634 AM EDT TUE JUL 29 2014

...A TOUCH OF MVFR THIS MORNING WITH SHOWERS AND STORMS LATER...

A SFC TROUGH IS SLIDING DOWN THROUGH NRN MICHIGAN EARLY THIS
MORNING WITH INCREASED LOW LEVEL MOISTURE DEVELOPING INTO A PERIOD
OF MVFR CIGS. AS THESE CLOUDS LIFT LATER THIS MORNING...A WEDGE OF
DEEPER DRIER AIR SWEEPS IN ACROSS PLN AND EVENTUALLY APN LATER
THIS AFTERNOON. WHILE NO SHOWERS/STORMS ARE EXPECTED ACROSS PLN
TODAY OR TONIGHT...ISOLATED TO SCATTERED ACTIVITY IS ANTICIPATED
AROUND THE OTHER AIRPORTS. CONFIDENCE IS NOT EXACTLY HIGH...BUT
DECENT ENOUGH FOR VCSH/VCTS TO BE USED IN THE TAFS. LOSS OF
DAYTIME HEATING AND DRIER AIR/LACK OF FORCING ALOFT WILL BRING A
QUIET NIGHT.

WINDS WILL BE WNW/NW GUSTING TO MAYBE 15 KNOTS THIS AFTERNOON ACROSS
NW LOWER AND LIGHTER OVER THE APN WAY.

&&

.MARINE...
ISSUED AT 318 AM EDT TUE JUL 29 2014

NOT MANY MARINE ISSUES TO BE CONCERNED WITH OVER THE NEXT SEVERAL
DAYS WITH SEVERAL SFC TROUGHS ROTATING INTO THE REGION...ALTERING
WIND DIRECTIONS BACK AND FORTH FROM SW TO N/NW. THE FIRST OF THESE
TROUGHS IS EXITING THIS MORNING. NW FLOW BEHIND IT WILL BACK MORE
WEST...BEFORE VEERING BACK NW/N ARRIVE TODAY...WITH NW FLOW BACKING
SW...THEN BACK TO N/NW TONIGHT. THIS MORE NORTHERLY FLOW IS
ANTICIPATED THROUGH LATER WEDNESDAY...PRIOR TO THE NEXT
TROUGH...WITH BACKING FLOW OUT OF THE SW. WIND SPEEDS ARE NOT
EXPECTED TO REACH ADVISORY LEVEL...AND WILL ACTUALLY BECOME LIGHTER
INTO THURSDAY WITH A WEAKER GRADIENT.


&&

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

&&

$$

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






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