Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KDTX 041949 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 349 PM EDT SAT JUL 4 2015 .SHORT TERM...THIS EVENING AND TONIGHT AXIS OF LOWER MID LEVEL HEIGHTS/TROUGHING NOW EXITING TO THE EAST... SE MICHIGAN AT THE INFLECTION POINT BETWEEN THIS FEATURE AND THE INBOUND UPPER RIDGE NOW CENTERED OVER THE MISSISSIPPI RIVER. ATTENDANT LOW LEVEL FRONT CURRENTLY EASING SOUTHEAST ACROSS NORTHERN LOWER MI WILL BECOME INCREASINGLY DIFFUSE AS UPPER HEIGHTS BEGIN TO REBOUND...THIS BOUNDARY STRUGGLING TO REACH MUCH BEYOND THE TRI- CITIES/NORTHERN THUMB BEFORE WASHING OUT THIS EVENING. A PERIOD OF LOCALIZED FORCED ASCENT...PERHAPS AUGMENTED BY LAKE BREEZE INTERACTIONS...WILL MAINTAIN A WINDOW FOR ISOLATED SHOWER/ THUNDERSTORM DEVELOPMENT ACROSS THIS CORRIDOR THROUGH THE EVENING ASSUMING ADEQUATE INSTABILITY. 12Z NAM AND CANADIAN SOLUTIONS REMAIN OVERZEALOUS WITH THE NEAR SURFACE MOISTURE CONTENT /DEWPOINT OF MID 60S/ RELATIVE TO CURRENT OBSERVATIONS...YIELDING A MORE UNSTABLE CONVECTIVE BOUNDARY LAYER AND CORRESPONDING GREATER COVERAGE OF CONVECTION. VARIOUS HI RES MODEL OUTPUT DO LEND SUPPORT TOWARD SEEING A COUPLE CELLS EMERGE AS PEAK HEATING WANES...WITH JUST ENOUGH INSTABILITY WITHIN THE COLUMN. SBCAPE IN THE BALLPARK OF 600-800 J/KG PER LATEST SPC MESOANALYSIS. ELSEWHERE...HIGHER DEGREE OF STABILITY WITH NO TANGIBLE FORCING WILL SUSTAIN A TRANQUIL 4TH OF JULY EVENING UNDER A CLEAR SKY. STEADY INCREASE IN UPPER HEIGHTS THROUGH THE NIGHT...UPPER RIDGE AXIS SETTLING ACROSS THE REGION BY MID MORNING SUNDAY. THIS WILL PROVIDE A NOTEWORTHY INCREASE THROUGHOUT THE THERMAL PROFILE. LOWS RANGING FROM MID 50S NORTH TO LOWER 60S METRO DETROIT. && .LONG TERM... SHORTWAVE RIDGE OVER THE UPPER MS VALLEY WILL TRANSIT THE CENTRAL GREAT LAKES ON SUNDAY BRINGING CONTINUED DEEP LAYER SUBSIDENCE. LACK OF FORCING AND A STRONG 700MB INVERSION WILL MAINTAIN CLEAR SKIES AND SUPPORT A DRY FORECAST WHILE MIXING TO 850MB TEMPERATURES AROUND 12C SUPPORTS HIGHS AT LEAST IN THE LOW 80S. EXPECTATION FOR FULL SUN SUGGESTS POTENTIAL FOR OVERACHIEVING TEMPS...NO CHANGE TO THE INHERITED FORECAST OF AROUND 85 DEGREES. WEAK HEIGHT FALLS AND INCREASINGLY CYCLONIC FLOW WILL SPREAD INTO SOUTHEAST MICHIGAN MONDAY IN ADVANCE OF AN AMPLIFYING TROUGH OVER THE NORTHERN TIER OF THE UNITED STATES. INCREASING SSW GRADIENT WILL ADVECT EVEN WARMER AIR INTO LOWER MICHIGAN WITH 850MB TEMPERATURES PROGGED TO RISE TO AROUND 17C. MID-LEVEL THETA-E AXIS WILL REMAIN WELL UPSTREAM, OVER THE WESTERN GREAT LAKES, WITHIN THE CORRIDOR OF STRONGEST FORCING ASSOCIATED WITH THE UPPER WAVE AND STRENGTHENING LLJ. THUS, ANOTHER DRY DAY ANTICIPATED WITH HIGH TEMPERATURES IN THE UPPER 80S...PERHAPS A 90 DEGREE READING IN THE SAGINAW VALLEY. NOCTURNAL WARM ADVECTION WILL BE ONGOING IN ADVANCE OF THE FRONT MONDAY NIGHT, SO FURTHER BUMPED UP MONDAY NIGHT LOW TEMPS TO 70 DEGREES. DECENT COLD FRONT STILL ON TRACK FOR TUESDAY. THERE STILL SEEMS TO BE SOME SLIGHT DIFFERENCES IN TIMING BETWEEN MODELS. NAM BEING A BIT FASTER ON THE LEADING EDGE OF THE PRECIPITATION. THAT BEING SAID...TUESDAY IS STILL SHAPING UP TO BE A WET DAY FOR SOUTHEAST MICHIGAN. PRESENT CONSENSUS HAS SOME SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE FOR THE WEE HOURS TUESDAY WITH RAIN CHANCES RAMPING UP TO THE LIKELY CATEGORY FOR THE MORNING COMMUTE. RAIN AND THUNDERSTORM POTENTIAL STAY ELEVATED INTO TUESDAY EVENING. SEVERE WEATHER THREAT STILL NOT SHOWING A GREAT DEAL OF OOMPH WITH BOTH CAPE AND SHOWALTER REGISTERING LOW POTENTIAL AND NEWER MODEL RUNS TRENDING THE JET DIVE TO OUR WEST. STILL TOO EARLY TO MAKE ANY DEFINITIVE CALLS. FRONT PROGGED TO MOVE THROUGH LATE TUESDAY/EARLY WEDNESDAY WITH A DECENT TEMP FALL. MID TO UPPER 80 DEGREE DAYS HELD OVER FROM THE WEEKEND WILL DWINDLE BELOW THE SEASONAL AVERAGE ONCE AGAIN. HIGHS BACK INTO THE MID 70S WEDNESDAY AND THURSDAY WITH OVERNIGHT LOWS IN THE MID 50S TO LOW 60S. REMAINDER OF THE PERIOD CARRIES WEAK CHANCES OF SHOWERS AND THUNDERSTORMS IN RESPONSE TO A MID LEVEL TROUGH PERSISTING OVER THE AREA. && .MARINE... TRANQUIL MARINE CONDITIONS THIS WEEKEND AS A WEAK PRESSURE GRADIENT WILL PERSIST ACROSS THE GREAT LAKES. SOUTHERLY WINDS WILL GRADUALLY INCREASE SUN NIGHT INTO MONDAY AHEAD OF A COLD FRONT APPROACHING THE WESTERN GREAT LAKES. STRONG OVER LAKE STABILITY WILL HOLD GUSTS BELOW 20 KNOTS. THE FRONT IS FORECAST TO TRAVERSE THE REGION LATE MONDAY NIGHT INTO TUESDAY...LEADING TO A VEERING OF THE WINDS TOWARD THE W-NW AND A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS. && .AVIATION...ISSUED 124 PM EDT SAT JUL 4 2015 A SCATTERED COVERAGE OF LATE DAY DIURNAL CU WILL FADE WITH THE LOSS OF DAYTIME HEATING THIS EVENING. THERE REMAINS A LOWER PROBABILITY FOR A SHOWER OR THUNDERSTORM TO IMPACT MBS THROUGH THIS EVENING AS A WEAK FRONTAL BOUNDARY ENTERS THE REGION. OTHERWISE CLEAR SKIES AND LIGHT WINDS THROUGH SUNDAY. THIS ENVIRONMENT MAY SUPPORT A BRIEF PERIOD OF SHALLOW FOG DEVELOPMENT DURING THE EARLY MORNING HOURS. //DTW THRESHOLD PROBABILITIES... * NONE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...MR LONG TERM....JC/DE MARINE.......JC AVIATION.....MR 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.