Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000 FXUS63 KDTX 081148 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 648 AM EST MON FEB 8 2016 .AVIATION... A GENERAL TREND TOWARD MORE PERSISTENT MVFR CEILING IS EXPECTED TO PROGRESS DURING THE LATE MORNING AND AFTERNOON. THIS WILL OCCUR AS COOLER AIR FILTERS IN FROM THE WEST WITH A SECONDARY FRONT AND AS MOISTURE MOVES UP FROM THE OHIO VALLEY ASSOCIATED WITH A STRONG CIRCULATION ALOFT. ANY PRECIPITATION WILL BE LIGHT RAIN THROUGH THE DAY AS BOUNDARY LAYER TEMPERATURE WILL BE COOLER BUT NOT ENOUGH FOR SNOW UNTIL CLOSER TO SUNSET. THE CIRCULATION MOVING UP FROM THE OHIO VALLEY TODAY IS THEN EXPECTED TO INTENSIFY NEAR THE SOUTH END OF LAKE HURON. THIS PROCESS WILL RESULT IN INCREASING COVERAGE OF IFR SNOW SHOWERS THAT WILL OCCUR MOSTLY OVER THE THUMB THROUGH TUESDAY MORNING. THIS IS SUBJECT TO ADJUSTMENT AND IFR VISIBILITY IN HEAVIER SNOW SHOWERS COULD OCCUR IN THE TERMINAL CORRIDOR OVERNIGHT. THIS WILL BE MONITORED FOR BETTER EVIDENCE BEFORE ADDING TO THE TAF. AT DTW... MOISTURE MOVING UP FROM THE OHIO VALLEY WILL ONLY PRODUCE SPRINKLES OF LIGHT RAIN FROM LATE MORNING THROUGH THE AFTERNOON...BUT WILL COMBINE WITH COOLER AIR MOVING IN FROM THE WEST FOR GREATER COVERAGE OF MVFR CEILING. MVFR CEILING AND VISIBILITY WILL OCCUR WITH GREATER FREQUENCY OF SNOW SHOWERS TONIGHT. LIGHT ACCUMULATION IS POSSIBLE BY SUNRISE TUESDAY...LESS THAN 1 INCH. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILING 5000 FT OR LESS TODAY AND TONIGHT. * HIGH FOR RAIN AS PRECIPITATION TYPE TODAY...AND SNOW TONIGHT. && .PREV DISCUSSION...ISSUED 337 AM EST MON FEB 8 2016 DISCUSSION... NWP CONTINUE TO STRUGGLE WITH ENERGETIC FLOW ACROSS NOAM AT PRESS TIME. VERY DYNAMIC TROUGH IS CLOSING OFF OVER THE WESTERN GREAT LAKES THIS MORNING. ITS EVOLUTION HAS LARGELY BEEN GUIDED BY A VERY HIGH AMPLITUDE UPSTREAM RIDGE AND A POWERFUL LOW DEEPENING OFF THE EASTERN SEABOARD IMMEDIATELY DOWNSTREAM. INTERACTION WITH A 165KT SUBTROPICAL JET STREAKING ACROSS THE GULF COAST STATES WILL ADDITIONALLY GUIDE THE DEEPENING LONGWAVE THROUGH TUESDAY. THE EMBEDDED WAVE OVER SAINT LOUIS AT 06Z THIS MORNING WAS UNIVERSALLY UNDERSIMULATED BY PRIOR MODEL CYCLES AND BETTER SAMPLING HAS ALLOWED GUIDANCE TO CONVERGE TOWARD A MORE IMPACTFUL EVOLUTION LOCALLY. SPECIFICALLY, AS THIS WAVE PIVOTS FROM STL TO LAKE ERIE, WEAK SURFACE CYCLOGENESIS IS ANTICIPATED INVOF THE LAKE. DEEP MOIST CYCLONIC UPPER FLOW WILL PROVIDE A FAVORABLE BACKGROUND WITHIN WHICH DEFORMATION AND STRONG SURFACE CONVERGENCE WILL BECOME INCREASINGLY ORGANIZED OVER LAKE HURON THROUGH THIS EVENING. CONFIDENCE THEN DECREASES DRAMATICALLY AS NWP SPREAD FALLS INTO AT LEAST 3 DISTINCT CAMPS. THE EC/ARW/NMM REPRESENT THE STRONGEST CLUSTERING THROUGH THE INITIAL CYCLOGENESIS AND THIS PREFERRED CLUSTER IS MOST STRONGLY REPRESENTED IN THE FORECAST. THE GFS/HRRR REMAIN THE MOST SIGNIFICANT OUTLIERS AND CONFIDENCE IN THOSE SOLUTIONS IS FURTHER DIMINISHED BY UNUSUALLY VOLATILE RUN-TO-RUN CONTINUITY BY THE RAP/HRRR. THROUGH 06Z TONIGHT, CONFIDENCE IS REASONABLY HIGH THAT THE ORGANIZING SURFACE TROUGH WILL BEGIN TO PIVOT ONSHORE IN THE THUMB. HAVING ORGANIZED OVER THE RELATIVELY WARM LAKE WATERS IN A MODESTLY UNSTABLE ENVIRONMENT , THERE IS POTENTIAL FOR SUBSTANTIAL MOISTURE POOLING AND THE FORECAST WILL HAVE TO BE MONITORED FOR A POTENTIAL OVERACHIEVING SCENARIO. THE NMM/ARW THEN ALLOW THE SURFACE CIRCULATION TO LATCH ON TO LAKE ERIE. ADDITIONAL DEEPENING BY A FEW ADDITIONAL MILLIBARS OVER THE LAKE -A PERFECTLY REASONABLE SCENARIO- THE STRENGTHENING CIRCULATION AND CONTINUED ONSHORE MOVEMENT OF THE SURFACE TROUGH OFFER POTENTIAL FOR SEVERAL ADDITIONAL INCHES OF SNOW AS WELL AS MORE AGGRESSIVE INLAND PENETRATION. THE MORE COARSE EC EXPECTEDLY PEELS THE LOW AWAY FASTER, CONFINING ACCUMS TO A SMALLER RANGE AND TO A SMALLER PORTION OF THE THUMB. CONSENSUS EC/ARW/NMM QPF YIELDS 12-HOUR ACCUMULATIONS OF 2-4" OVER THE NEXT 24 HOURS AND 24-HOUR TOTALS OF 4-7" IN EASTERN PORTIONS OF THE THUMB. THERE REMAINS CONSIDERABLE UNCERTAINTY IN THE EVOLUTION OF CRITICAL SURFACE FEATURES, BUT POTENTIAL FOR A WWA-WORTHY SCENARIO IS HIGH ENOUGH TO WARRANT TAKING AN INITIAL STAB AT A HEADLINE. WORTH NOTING THAT 06Z NAM REMAINS A BIT OF AN OUTLIER, BUT HAS SHOWN A STRONG ADJUSTMENT TOWARD AFOREMENTIONED PREFERRED CONSENSUS. FOR TODAY, EXPECTING LITTLE MORE THAN OCCASIONAL LIGHT SHOWERS ACROSS THE EASTERN CWA AS BOUNDARY LAYER TEMPERATURES LIKELY REMAIN TOO WARM TO SUPPORT SNOW UNTIL NEAR OR SHORTLY AFTER SUNSET. A LATE WEEK CLIPPER WILL POTENTIALLY BRING LIGHT ACCUMULATIONS ON FRIDAY IN ADDITION TO MARKING THE LEAD EDGE OF A MUCH COLDER AIRMASS. HIGHS WILL STRUGGLE TO REACH 20 DEGREES WITH SAT AND/OR SUNDAY POTENTIALLY STRUGGLING TO REACH 10 DEGREES. CONSECUTIVE MORNINGS OF SUB-ZERO LOWS WILL ALSO BE POSSIBLE AND WIND CHILL READINGS MAY APPROACH ADVISORY CRITERIA AT TIMES. MARINE... A BROAD AREA OF LOW PRESSURE WILL SETTLE OVER LAKE HURON AND LOWER MICHIGAN TODAY. THIS WILL LEAD TO LIGHT AND VARIABLE WIND OVER MARINE AREA TODAY THROUGH TONIGHT BUT WITH AN INCREASINGLY ACTIVE SNOW SHOWER PATTERN. THE SYSTEM WILL DRIFT TOWARD LAKE ONTARIO DURING TUESDAY AND LEAVE NORTHERLY WIND INCREASING TO MODERATE STRENGTH BY TUESDAY NIGHT. WHILE WIND HEADLINES ARE NOT ANTICIPATED...MARINE CONDITIONS WILL WORSEN AS COLDER AIR MOVES IN AND COMBINES WITH THE MODERATE WIND FIELD FOR BUILDING WAVES AND STRONGER SNOW SQUALLS. THIS WILL LAST INTO THURSDAY AND THEN WIND WILL DIMINISH THROUGH FRIDAY WHILE ARCTIC AIR REMAINS IN PLACE INTO NEXT WEEKEND. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 PM EST TUESDAY FOR MIZ049-054-055-062-063. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BT DISCUSSION...JVC MARINE.......BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

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