Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDTX 291155
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
755 AM EDT MON JUN 29 2015


.AVIATION...

A SHORTWAVE WILL LIFT NORTHWARD INTO OHIO TODAY BEFORE PUSHING INTO
PORTIONS OF WESTERN LAKE ERIE TONIGHT. SCATTERED SHOWER ACTIVITY
WILL BEGIN TO PUSH ACROSS THE OHIO BORDER BY MIDDAY BECOMING
NUMEROUS TO POTENTIALLY WIDESPREAD DURING THE LATE AFTERNOON AND
EVENING HOURS ACROSS THE DETROIT METRO AREA. LACK OF A STRONG WIND
PROFILE IN BEHIND THIS SYSTEM WILL LIMIT THE AMOUNT OF DRY AIR
ADVECTION. THERE IS HIGH CONFIDENCE THAT NOCTURNAL COOLING AND
SATURATION WILL LEAD TO IFR TO POSSIBLE LIFR CIG HEIGHTS LATE
TONIGHT. PERSISTENT LIGHT GRADIENT WIND TOMORROW MORNING WILL LIMIT
FOG.

//DTW THRESHOLD PROBABILITIES...

* HIGH IN CIGS AOB 5KFT AFTER 23Z MONDAY.

* LOW IN THUNDERSTORMS THIS AFTERNOON AND EVENING.

&&

.PREV DISCUSSION...ISSUED 415 AM EDT MON JUN 29 2015

SHORT TERM...TODAY AND TONIGHT

A DIFFICULT FORECAST FOR TODAY WITH ANOTHER SHORTWAVE SET TO PIVOT
NORTHEASTWARD THIS EVENING TOWARD THE WESTERN BASIN OF LAKE ERIE.
THE SPREAD OF 29.00Z MODEL SOLUTIONS IS AGAIN HIGH WITH DISAGREEMENT
CONTINUING ON THE INTEGRITY AND TRACKING OF COOL SIDE DEFORMATION
THAT WILL DEVELOP ALONG THE NORTHERN PERIPHERY OF THE
SHORTWAVE/850MB MIDLEVEL LOW CIRCULATION.

LATEST WATER VAPOR IMAGERY SHOWS VARIOUS ABSOLUTE CYCLONIC MAXIMA
WITHIN THE HIGH AMPLITUDE/UPPER LEVEL NOAM TROUGH. A WEAK SHORTWAVE
EDDY WAS ABLE TO SLIDE OUT OF WISCONSIN OVERNIGHT AND EMERGE OVER
SECTIONS OF SOUTHWESTERN MICHIGAN. MODEST MOISTURE PUSHED AHEAD OF
THIS CIRCULATION IN COMBINATION WITH SOME SEMBLANCES OF A LEAD
MIDLEVEL DEFORMATION WING TO MAINTAIN A PERSISTENCE OF SOME HIGH
BASED SHOWERS NEAR SAGINAW BAY. WEAK WARM AIR ADVECTION IS ALSO
OCCURRING AS A MERE CONSEQUENCE OF THICKNESSES INCREASING WITH THE
MAIN COLD ANOMALY FROM LAST WEEKEND VACATING THE REGION TO THE EAST.
THE 29.00Z KAPX RAOB CAPTURED A STEEP LAPSE RATE POCKET IN THE 700-
600MB LAYER. SEE NO REASON SHOWERS CANNOT PERSIST IN AN ISOLATED
COVERAGE ACROSS THE NORTHERN CWA THROUGH DAYBREAK. USUALLY WITNESS
THESE NOCTURNAL HIGH BASED SHOWERS WEAKEN WITH THE ONSET OF DIURNAL
HEATING AND THIS COULD BE THE CASE HERE.

THE SHORTWAVE OF PARTICULAR INTEREST FOR THE FORECAST THIS AFTERNOON
AND EVENING IS THE ONE THAT HAS LARGELY DESCENDED INTO THE BASE OF
THE TROUGH OVER PORTIONS OF ILLINOIS. MODEL DATA SUGGESTED THIS
SHORTWAVE CENTER TO FOCUS NEAR/BEHIND SOME OVERNIGHT CONVECTION.
THIS HAS APPEARED TO HAVE HAPPENED IN SOME CAPACITY GIVEN THE LOOK
OF THE WV IMAGERY AND THE SURFACE REFLECTION CENTER ANALYZED IN THE
HOURLY MSAS DATSET. TO WHAT EXTENT REMAINS IN QUESTION AS THERE ARE
DIFFERENCES IN THE PARENT SHORTWAVE/PV ANOMALY STRUCTURE BETWEEN THE
ECWMF AND NAM. THE ECMWF SUGGESTS SOME MAIN ENERGY REMAINS SHEARED
AND LAGGED BACK ACROSS WISCONSIN...WHILE THE NAM SUGGESTS THE MAIN
VORTICITY CENTER HAS LARGELY COLLECTED OVER ILLINOIS. WARMING TOPS
IN IR IMAGERY SUGGESTS A LESS DEVELOPED SOLUTION THUS FAR. FOR
TODAY...THERE IS A CONSENSUS THAT ADVERTISES THE PV ANOMALY OVER
ILLINOIS WILL SLOWLY PIVOT THROUGH THE TROUGH BASE THIS MORNING
BEFORE LIFTING TO THE NORTHEAST FOR THIS AFTERNOON. AN ARC OF
SHOWERS AND EMBEDDED THUNDER IS EXPECTED TO LIFT AND ROTATE
NORTHEASTWARD TOWARD THE MI/OH STATELINE FROM THE SOUTH ALONG THE
LEAD CVA PUSH. SCATTERED SHOWERS WITH WEAK TO NIL LARGE SCALE
ORGANIZATION WILL BE POSSIBLE IN ADVANCE OF THIS FEATURE THIS
MORNING. GENERALLY TRENDED POPS FROM A CHANCE THIS MORNING ACROSS
THE FAR SOUTH TO LIKELY/NUMEROUS FOR THE SOUTHERN TWO TIERS LATE
THIS AFTERNOON AND EVENING. THE PRIMARY FORCING TO WATCH FOR WILL BE
COOL SIDE DEFORMATION. SOLUTIONS SUGGESTS THE DEVELOPED ARC OF
SHOWERS MAY LIFT NEAR THE MI/OH STATELINE WHILE PIVOTING. IT APPEARS
THAT HI-RESOLUTION CAMS ARE REALLY STRUGGLING WITH  DEVELOPING
SYNOPTIC SCALE STRATIFORM PRECIPATION IN THIS EVENT...AND RELIED
MORE ON DETERMINISTIC OUTPUT FOR THIS FORECAST.

GIVEN THE FORCING AND THE SATURATED SOILS FROM THE EVENT THIS
WEEKEND...DID GIVE SOME THOUGHT TO AN AREAL FLOOD WATCH FOR LENAWEE
AND MONROE COUNTIES. WILL FORGO AN ISSUANCE THIS ISSUANCE AS THERE
REMAINS A HIGH AMOUNT OF UNCERTAINTY. IT APPEARS THE POTENTIAL FOR
HIGHER RAIN RATES SHOULD FAVOR THE THIN RIBBON OF 950MB THETA E THAT
WILL EXISTS IN THE SOUTHERLY FLOW IN ADVANCE OF THE 850MB LOW
CIRCULATION. FROM THIS VANTAGE POINT...THE SUPPORT OF THE AVAILABLE
SOLUTIONS SUGGESTS IT WILL MISS THE AREA TO THE SOUTH AND EAST.
OUTGOING GRIDS HAS QPF IN THE .3 TO .5 INCH RANGE FOR MONROE AND
LENAWEE COUNTIES. ONE ITEM OF SOME CONCERN IS VERY SLOW 850-300MB
MEAN WIND...SUPPORTIVE OF SLUGGISH CELL MOTION TODAY.

CONDITIONS TONIGHT WILL BE PRIME FOR A SUBSTANTIAL BLANKET OF LOW
CLOUD AND CEILING HEIGHTS. ENOUGH OF A GRADIENT WIND IS EXPECTED TO
BE IN PLACE TO DISCOURAGE FOG FORMATION.

LONG TERM...TUESDAY THROUGH SUNDAY

LONGWAVE TROUGH WILL CONTINUE TO RESIDE OVER THE GREAT LAKES AND NEW
ENGLAND THROUGH FRIDAY NIGHT. SMALLER-SCALE TROUGHS EMBEDDED WITHIN
THE LONGWAVE WILL PROVIDE PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS THROUGH THIS PERIOD. NEXT SHORTWAVE IN THE SERIES WILL
TRACK THROUGH THE AREA TODAY/TONIGHT...KICKING SURFACE LOW PRESSURE
ACROSS THE NORTHERN OHIO VALLEY AND FAR SOUTHERN MICHIGAN. NEXT WAVE
WILL FOLLOW CLOSELY BEHIND...DROPPING DOWN THROUGH WISCONSIN AND
MICHIGAN STARTING EARLY ON TUESDAY. AT THE SURFACE...RENEWED HEIGHT
FALLS WILL BROADEN THE AREA OF SURFACE LOW PRESSURE CENTERED OVER
LAKE ERIE EARLY IN THE DAY...EXPANDING IT BACK TO ENCOMPASS LOWER
MICHIGAN. POTENTIAL FOR SHOWERS/TSTORMS WILL EXIST ACROSS THE AREA
ON TUESDAY...BUT MAY BE A BIT MORE FOCUSED OVER THE FAR EASTERN
PORTION OF THE FORECAST AREA BEHIND THE ORIGINAL SURFACE LOW
PRESSURE CENTER OVER LAKE ERIE...AND THEN ALSO OVER THE FAR WESTERN
PORTION OF THE FORECAST AREA...CLOSER TO UPPER SHORTWAVE ENERGY.
SEVERE WEATHER IS NOT EXPECTED AS INSTABILITY THROUGH THE COLUMN
OVERALL LOOKS LIMITED...AND A LIGHT WIND FIELD ALSO LIMITS SHEAR.
STORMS WILL HAVE POTENTIAL TO PRODUCE LOCALLY HEAVY
RAINFALL...SUPPORTED BY VERY SLOW STORM MOTION AND HIGH PWAT VALUES
BETWEEN 1.0 AND 1.5 INCHES.

NEXT SHORTWAVE IS EXPECTED TO CLIP ACROSS MICHIGAN LATE WEDNESDAY
INTO WEDNESDAY NIGHT. PRECIP CHANCES CONTINUE TO LOOK LOW FOR THE
DAYTIME AS DEEPER MOISTURE WILL HAVE SHIFTED EAST...HOWEVER STEEP
LAPSE RATES FROM THE SURFACE THROUGH 700MB AND POTENTIAL FOR LAKE
BREEZES TO KICK OFF CONVECTION WARRANTS A CONTINUED MENTION FOR
SHOWERS/TSTORMS. COLD FRONT DROPPING THROUGH THE AREA DURING THE
EVENING AND OVERNIGHT MAY ALSO KICK OFF A FEW CELLS...BUT COVERAGE
LOOKS LIMITED GIVEN LACK OF GOOD MOISTURE ADVECTION AND OVERNIGHT
TIMING.

HIGH PRESSURE LOOKS TO EXPAND OVER THE AREA THURSDAY BRINGING A
BRIEF RESPITE FROM PRECIPITATION CHANCES...BEFORE ANOTHER WAVE
TRACKING THROUGH THE AREA RENEWS CHANCES FOR FRIDAY. THE PATTERN
THEN LOOKS TO CHANGE FOR THE HOLIDAY WEEKEND AS THE LONGWAVE TROUGH
SHIFT EAST AND IS GRADUALLY REPLACED BY UPPER RIDGING THAT LASTS
INTO SUNDAY.

THE PARADE OF UPPER WAVES FROM THE NORTHWEST WILL MAINTAIN COOLER
THAN NORMAL MAX TEMPERATURES (IN THE 70S) THROUGH THE END OF THE
WEEK. SLIGHTLY WARMER...AND CLOSER TO NORMAL...TEMPERATURES ARE THEN
EXPECTED OVER THE WEEKEND AS UPPER RIDGING BUILDS.

MARINE...

FAIRLY LIGHT WINDS WILL PERSIST ACROSS THE CENTRAL GREAT LAKES MUCH
OF TODAY. A LOW PRESSURE SYSTEM TRACKING THROUGH THE OHIO VALLEY
WILL THEN BRING AN INCREASE IN WINDS THIS EVENING AND EARLY
TONIGHT...PRIMARILY OVER WESTERN LAKE ERIE WHERE WINDS WILL TURN
EASTERLY. WINDS WILL WEAKEN LATE TONIGHT AS THE LOW LIFTS THROUGH
LAKE ERIE AND INTO ONTARIO. AN UPPER LEVEL DISTURBANCE WILL THEN
DROP INTO MICHIGAN TUESDAY. THIS WILL EXPAND LOW PRESSURE BACK
THROUGH THE CENTRAL GREAT LAKES...KEEPING WINDS LIGHT AS IT SITS
OVER THE AREA.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM 6 PM EDT THIS EVENING THROUGH LATE
     TONIGHT FOR MIZ083.

LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 4 AM EDT TUESDAY FOR
     LEZ444.

&&

$$

AVIATION.....CB
SHORT TERM...CB
LONG TERM....HLO
MARINE.......HLO


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.