Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 03/19/12


SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
230 PM PDT SAT MAR 17 2012 .SYNOPSIS... A COLD AND UNSTABLE MOIST AIRMASS WILL AFFECT THE AREA THROUGH SUNDAY...WITH SCATTERED SHOWERS...A SLIGHT CHANCE OF THUNDERSTORMS AND MOUNTAIN SNOW. SNOW LEVELS ARE EXPECTED TO LOWER OVERNIGHT WHICH MAY AFFECT THE ANTELOPE VALLEY FOOTHILLS...AS WELL AS THE INTERIOR SAN LUIS OBISPO AND CUYAMA VALLEYS. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH EARLY NEXT WEEK. && .SHORT TERM (TODAY-TUE)...THE BULK OF THE PRECIPITATION HAD EXITED THE EAST PORTION OF LA COUNTY EARLY THIS AFTERNOON THOUGH PICTURES FROM SPACE INDICATED A RELATIVELY LARGE OPEN CELL CUMULUS FIELD IN THE VICINITY AND UPSTREAM OF THE TROUGH AXIS CENTERED OVER THE OFFSHORE WATERS. GOES SOUNDER AND RUC INDICATED NEGATIVE LI`S OVER THE OFFSHORE WATERS NORTH OF POINT CONCEPTION AND THE INSTABILITY WAS GRADUALLY APPROACHING THE AREA. STABILITY WILL DECREASE THROUGH THE EVENING AND THE RUC INDICATED MINUS 3.5 LI`S LATER THIS EVENING. UNSTABLE AIR MASS WILL PERSIST OVER THE AREA THROUGH SUNDAY AND A THREAT OF THUNDERSTORMS AND SHOWERS WILL EXIST. SHOWERS AND THUNDERSTORMS WILL MOVE EAST THROUGH THE EVENING AND THEN MOVE SOUTHEAST OVERNIGHT THROUGH SUNDAY. OTHERWISE GUIDANCE DIFFERED FROM PREVIOUS RUNS AND BETWEEN SUITES WITH THE APPROACHING TROUGH CURRENTLY NEAR 41/143. WILL CONTINUE WITH SLIGHT CHANCE OF LIGHT PRECIPITATION AS WARM FRONT LIKE BOUNDARY WITH WEAK ASCENDING NORTHWEST FLOW APPROACHES. WILL CONTINUE THE WARMING TREND MONDAY THROUGH TUESDAY THOUGH TEMPERATURES WILL LIKELY BE 5 TO 15 DEGREES BELOW SEASONAL NORMAL MONDAY AND AROUND 5 DEGREES BELOW NORMAL TUESDAY. .LONG TERM (WED-SAT)...HAVE ADDED A CHANCE OF LIGHT PRECIPITATION NEXT SATURDAY. THERE IS A CHANCE A SURFACE FRONT WILL NOT DISSIPATE UPSTREAM FROM THE AREA AND MOVE ASHORE NEXT SATURDAY. ECM AND GFS OPERATIONAL GUIDANCE WERE RELATIVELY CONSISTENT AS WAS THE GFS ENSEMBLE WITH PREVIOUS RUNS AND INDICATED A SURFACE FRONT MOVING ASHORE. OTHERWISE A WARMING TREND WILL CONTINUE WEDNESDAY WITH TEMPERATURES SEVERAL DEGREES ABOVE NORMAL THEN A GRADUAL COOLING TREND IS EXPECTED AS ONSHORE FLOW INCREASES AND HEIGHTS/THICKNESSES FALL/LOWER OVER THE AREA AHEAD OF THE APPROACHING AND LANDFALLING FRONT THURSDAY THROUGH SATURDAY. && .AVIATION...16/1755Z... LOW CLOUDS ACROSS COAST AND VALLEY AREAS WILL BEGIN TO BREAK OUT THIS AFTERNOON. CIGS WILL LIFT INTO THE HIGH MVFR CATEGORY AND THERE IS A CHANCE THAT MANY SITES WILL SCATTER OUT...ESPECIALLY S OF PT CONCEPTION...BEFORE LOW CLOUDS FILL IN AGAIN DURING THE EVENING. A FRONTAL SYSTEM WILL SPREAD INCREASING CLOUDS AND RAIN ACROSS THE AREA FROM NW TO SE TONIGHT INTO SAT...DEVELOPING ACROSS SLO AND SBA COUNTIES BETWEEN MIDNIGHT AND 5 AM...AND REACHING LOS ANGELES COUNTY BY MID MORNING SATURDAY. GUSTY S-SE WINDS WILL AFFECT MANY AIRFIELDS BETWEEN THE HOURS OF 06Z-10Z N OF PT CONCEPTION...TO 10Z-13Z FURTHER SOUTH. THE EXCEPTION WILL BE IN THE DESERT AIRFIELDS WHERE GUSTY SW WINDS ARE EXPECTED THROUGH MOST OF THE FORECAST PERIOD. KLAX...LOWER TO MODERATE CONFIDENCE IN TAF. THERE IS A 40 PERCENT CHANCE THAT MVFR CIGS WILL SCATTER OUT AFTER 20Z. THERE IS A 30 PERCENT CHANCE THAT LOWER CIGS WILL RETURN +/- 2 HOURS FROM TAF TIME OF 04Z...OR THAT CIGS WILL BE IN THE MVFR CATEGORY THROUGH LATE TONIGHT. THERE IS A 20 TO 30 PERCENT CHANCE THAT EAST WINDS WILL EXCEED 10 KNOTS AS EARLY AS 10Z SAT. KBUR...MODERATE CONFIDENCE IN TAF. THERE IS A 40 PERCENT CHANCE THAT MVFR CIGS WILL SCATTER OUT AFTER 20Z. THERE IS A 30 PERCENT CHANCE THAT MVFR CIGS WILL RETURN +/- 2 HOURS FROM TAF TIME OF 04Z. && .LOX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING (SEE LAXWSWLOX). WIND ADVISORY (SEE LAXNPWLOX). WINTER WEATHER ADVISORY (SEE LAXWSWLOX). GALE WARNING (SEE LAXMWWLOX). SMALL CRAFT ADVISORY (SEE LAXMWWLOX). HIGH SURF ADVISORY (SEE LAXCFWLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && $$ PUBLIC...30 AVIATION...SMITH SYNOPSIS...BARTLING WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
830 PM EDT SUN MAR 18 2012 .UPDATE... UPPER RIDGE HAS AMPLIFIED OVER THE CENTRAL GULF NWD INTO THE TENNESSEE VALLEY. A WEAK IMPULSE SLID DOWN THE EAST SIDE OF THE RIDGE...INTERACTED WITH THE SEABREEZE TO PRODUCE SCATTERED SHOWERS/STORMS MOVING SOUTH ACRS OUR GA ZONES. THE ACTIVITY ENDED QUICKLY WITH LOSS OF HEATING. THE RUC SHOWS THE RIDGE CONTINUING TO STRENGTHEN OVERNIGHT WITH MOSTLY CLEAR SKIES WITH SOME CIRRUS SPILLING OVER THE RIDGE. MODEL SOUNDINGS INDICATE DRY AIR ABOVE THE SURFACE AND THEREFORE EXPECT LIMITED FOG DEVELOPMENT. PATCHY GROUND FOG IS FORECAST. MOIST SE FLOW ACROSS THE SOUTHERN ZONES COULD PRODUCE LOCALLY DENSE FOG IN THIS AREA. HAVE ADDED PATCHY DENSE FOG FROM OCALA TO BUNNELL NWD ALONG THE COAST. ALSO HAVE DROPPED POPS FOR THE REMAINDER OF THE NIGHT. && .AVIATION... MVFR VSBY EXPECTED TO DEVELOP AROUND MIDNIGHT AT VQQ AND GNV THEN BTWN 07Z AND 09Z AT REMAINING TERMINALS. BRIEF PERIOD OF IFR IS POSSIBLE AROUND SUNRISE AT INLAND LOCATIONS. VFR WILL RETURN BY 14Z. && .MARINE... BENIGN CONDITIONS ARE REPORTED OVER THE WATERS. LIGHT WINDS/SEAS ARE EXPECTED TO CONTINUE THROUGH MIDWEEK. NO CHANGES THIS EVENING. RIP CURRENTS: LOW RISK THROUGH MONDAY. && .PRELIMINARY POINT TEMPS/POPS... AMG 58 87 58 84 / 20 10 10 20 SSI 60 74 61 75 / 10 10 10 20 JAX 57 85 57 82 / 0 0 10 20 SGJ 60 79 61 78 / 0 0 10 20 GNV 56 85 57 83 / 0 0 10 20 OCF 57 85 58 83 / 0 0 10 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ TRABERT/ENYEDI/KEEGAN
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
144 PM EDT SAT MAR 17 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION TONIGHT. A BACKDOOR COLD FRONT WILL MOVE SOUTH INTO THE AREA THIS WEEKEND AND DISSIPATE EARLY NEXT WEEK. ATLANTIC HIGH PRESSURE WILL THEN REGAIN CONTROL OF THE PATTERN THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN CHANGE TO THE PREVIOUS FORECAST WAS TO PUSH RAIN CHANCES BACK A BIT MORE TOWARD EVENING. DECENT BATCH OF MID LEVEL CLOUDS OVER MOST OF THE FORECAST AREA HAS KEPT TEMPERATURES DOWN A TAD AND THIS IS SLOWING DESTABILIZATION. ALSO NOTICED SLIGHTLY WARMER 500 MB TEMPS THIS AFTERNOON ACROSS THE INTERIOR AS PER LATEST RUC AND THIS IS LIKELY ALSO CONTRIBUTING TO SLOWER CONVECTIVE DEVELOPMENT. OTHERWISE... SEE PREVIOUS DISCUSSION FOR MORE DETAILS ON CONVECTIVE EVOLUTION/SEVERE WX THREAT LATER THIS AFTERNOON/EVENING. =============================================================== == DISCUSSION FOR CHATHAM COUNTY EMERGENCY MANAGEMENT AGENCY == =============================================================== ANOTHER ACTIVE DAY FOR SHOWERS AND TSTMS AROUND THE SAVANNAH METRO AREA LATE THIS AFTERNOON AND EVENING. INITIALLY... MOST OF THE ACTIVITY IS EXPECTED TO FIRE JUST WEST OF THE CITY ALONG THE INLAND MOVING SEA BREEZE...BUT COULD PUSH BACK TOWARD THE DOWNTOWN AREA LATE IN THE AFTERNOON INTO THIS EVENING. THE TIME FOR GREATEST IMPACTS APPEARS TO BE FROM 1700-2200 EDT. CONDITIONS WILL FAVOR WINDS IN EXCESS OF 40 MPH...PENNY SIZE HAIL AND FREQUENT CLOUD-TO- GROUND LIGHTNING WITH ANY TSTMS THAT DEVELOP TODAY. A SEVERE TSTM IS ALSO POSSIBLE WITH HAIL 1 INCH OR LARGER AND/OR DAMAGING WINDS IN EXCESS OF 60 MPH. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... TONIGHT...CLUSTERS OF STRONG TO SEVERE TSTMS WILL LIKELY BE ONGOING AFTER SUNSET AS BOTH INSTABILITY AND LOW-LEVEL CONVERGENCE ALONG MESOSCALE BOUNDARIES PEAK. ACTIVITY WILL GRADUALLY WIND DOWN THROUGH THE EVENING AND OVERNIGHT...BUT IT WILL LIKELY TAKE A GOOD PORTION OF THE NIGHT FOR ACTIVITY TO DISSIPATE. WILL SHOW LIKELY TO CHANCE POPS ALL AREAS THIS EVENING WITH RAIN CHANCES DIMINISHING OVERNIGHT. LOWS WILL RANGE FROM THE UPPER 50S INLAND TO THE LOWER 60S AT THE BEACHES AND DOWNTOWN CHARLESTON. /ST SUNDAY AND MONDAY...UPPER LEVEL RIDGING EXTENDING FROM THE GULF OF MEXICO WILL SHIFT TOWARD THE EAST COAST AND BECOME MORE AMPLIFIED EARLY NEXT WEEK. THE MAIN SURFACE FEATURE DRIVING MUCH OF THE SENSIBLE WEATHER SUNDAY AND MONDAY WILL BE A BACKDOOR FRONT DESCENDING SOUTHWARD INTO THE FORECAST AREA. MOISTURE AND CONVERGENCE IN THE VICINITY OF THIS FRONT...WHEN COMBINED WITH DIURNAL INSTABILITY AND SEABREEZE FORCING...WILL MAINTAIN RAIN CHANCES BOTH SUNDAY AND MONDAY. ALTHOUGH THERE REMAINS SOME DISAGREEMENT AMONG NUMERICAL MODEL SOLUTIONS REGARDING THE SOUTHWARD PROGRESSION OF THE FRONT...THERE IS A GENERAL CONSENSUS THAT THE FEATURE WILL AT LEAST SLIP INTO THE CHARLESTON TRI COUNTY REGION ON SUNDAY...BEFORE BECOMING DIFFUSE AND DISSIPATING LATE SUNDAY INTO MONDAY. DESPITE LITTLE TO NO DYNAMICS ALOFT AND WEAK VERTICAL SHEAR...THERE WILL BE SUFFICIENT MOISTURE CONVERGENCE AND INSTABILITY TO SUPPORT ISOLATED TO SCATTERED DIURNAL CONVECTION GENERALLY AHEAD OF THE SEABREEZE DURING THE AFTERNOON HOURS. THE CHARLESTON TRI COUNTY AREA AGAIN APPEARS TO BE THE MOST FAVORED LOCATION FOR CONVECTIVE COVERAGE ON SUNDAY...AS IT REMAINS CLOSEST TO THE BOUNDARY AND ANY ASSOCIATED WEAK WAVE OF LOW PRESSURE. HAVE INDICATED POPS IN THE 30 PERCENT RANGE FOR MOST INLAND AREAS NORTH OF INTERSTATE 16...WITH NEAR 40 PERCENT CHANCES IN THE FAR NORTHWEST TIER ZONES. SINCE THE FRONT WILL BE MORE DIFFUSE ON MONDAY AND COULD PROVIDE LESS FOCUS FOR CONVECTION THAN THE SEABREEZE...HAVE JUST INDICATED SLIGHT CHANCE POPS AWAY FROM THE COAST MONDAY AFTERNOON. HAIL WOULD AGAIN BE THE MAIN RISK WITHIN STRONGEST THUNDERSTORMS...ESPECIALLY CONSIDERING UNSEASONABLY LOW 500 MB TEMPERATURES WITHIN A PERSISTENT COLD POOL ALOFT. A SUBTLE HIGH TEMPERATURE GRADIENT COULD DEVELOP BOTH SUNDAY AND MONDAY DEPENDING ON THE LOCATION OF THE BACKDOOR FRONT. HOWEVER THE BOUNDARY IS EXPECTED TO HAVE LITTLE OVERALL IMPACT ON THE UNSEASONABLY WARM CONDITIONS...WITH HIGH TEMPERATURES RANGING FROM THE UPPER 70S CHARLESTON TRI COUNTY REGION TO THE LOW TO MID 80S AWAY FROM THE COAST ELSEWHERE. TUESDAY...A MORE SOLID ONSHORE FLOW WILL DEVELOP BY TUESDAY...AS ATLANTIC HIGH PRESSURE BUILDS FROM THE NORTH. THE RESIDUAL FRONT AND WAVE OF LOW PRESSURE WILL RESEMBLE MORE OF A COASTAL TROUGH FEATURE...PUSHING ONSHORE FROM THE WESTERN PERIPHERY OF THE ATLANTIC HIGH. EXPECT ENOUGH ATLANTIC MOISTURE AND FORCING FROM THE WEAK TROUGH TO SUPPORT ISOLATED SHOWERS/THUNDERSTORMS TUESDAY AFTERNOON...YET WITH LESS COVERAGE EXPECTED THAN PREVIOUS DAYS. HIGH TEMPERATURES COULD BE JUST A DEGREE OR TWO COOLER WITHIN THE ONSHORE FLOW...WHILE STILL GENERALLY RANGING FROM THE UPPER 70S TO LOWER 80S. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... BROAD UPPER RIDGING AND ATLANTIC SURFACE HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH MID WEEK...BEFORE THE FORECAST BECOMES MORE UNCERTAIN INTO THE LATE WEEK PERIOD. MID RANGE MODELS INDICATE A DEEP UPPER TROUGH STEADILY PROGRESSING TOWARD THE EAST COAST THURSDAY...POSSIBLY CUTTING OFF INTO A BROAD UPPER LOW BY FRIDAY. THIS COULD DRIVE A SURFACE FRONT TOWARD THE REGION AND INCREASE RAIN CHANCES LATE IN THE WEEK. CONFIDENCE IN FORECAST DETAILS THURSDAY AND FRIDAY IS QUITE LOW AT THIS TIME HOWEVER...AS THERE IS CONSIDERABLE TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS. HAVE THUS PREFERRED TO REMAIN RATHER CONSERVATIVE WITH RAIN CHANCES THIS FAR OUT IN THE FORECAST PERIOD...CAPPING POPS BELOW 15 PERCENT UNTIL MODEL CONSENSUS IMPROVES. HAVE ALSO CONTINUED TO ADVERTISE ABOVE NORMAL TEMPERATURES...REACHING AT LEAST THE MID TO UPPER 70S INTO THE WEEKEND AWAY FROM THE LOCALLY COOLER COASTLINE. && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... SHOWERS/TSTMS APPEAR TO BE THE MAIN IMPACT TO AVIATION THIS PERIOD. LATEST THINKING IS THAT SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE INLAND MOVING SEA BREEZE THIS AFTERNOON...POSSIBLY COLLIDING WITH ACTIVITY FARTHER WEST...THEN POSSIBLY MOVING BACK TOWARD THE COAST TOWARD EVENING. HAVE MAINTAINED TSRA AT KSAV BUT PUSHED BACK THE TIMING A BIT AS CONVECTION APPEARS TO BE A BIT SLOWER THAN YDAY. OTHERWISE...POSSIBLE MVFR FOG TOWARD DAYBREAK BUT CHANCES TOO LOW TO MENTION ATTM. EXTENDED AVIATION OUTLOOK...ELEVATED POTENTIAL FOR LATE NIGHT/EARLY MORNING FOG AND/OR LOW CEILINGS INTO EARLY NEXT WEEK. && .MARINE... QUIET MARINE CONDITIONS THROUGH TONIGHT...ALTHOUGH TSTMS COULD POSE A RISK FOR MARINERS CLOSER TO THE BEACHES LATE THIS AFTERNOON AND EVENING. WINDS WILL GENERALLY BE 10 KT OR LESS WITH SEAS 3 FT OR LESS. SUNDAY THROUGH WEDNESDAY...THE BACKDOOR COLD FRONT WILL LIKELY SLIP INTO THE SOUTH CAROLINA WATERS ON SUNDAY. THE PRESSURE GRADIENT WILL REMAIN RATHER WEAK AS THIS FEATURE MOVES INTO THE AREA...AND EXPECT LIGHT WIND FIELDS TO POTENTIALLY BE QUITE VARIABLE THROUGH MONDAY. ONCE THE FRONT BECOMES DIFFUSE AND DISSIPATES ON MONDAY...ATLANTIC HIGH PRESSURE WILL BUILD FROM THE NORTH AND BECOME THE DOMINATE FEATURE THROUGH THE REMAINDER OF THE PERIOD. THIS WILL SUPPORT SLIGHTLY STRONGER ONSHORE FLOW...YET EXPECT WINDS SPEEDS TO REMAIN 15 KT OR LESS TUESDAY AND WEDNESDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
137 PM EDT SAT MAR 17 2012 .SYNOPSIS... HIGH PRESSURE CENTERED OFF THE ATLANTIC COAST WILL BE THE MAIN WEATHER FEATURE ACROSS THE REGION TODAY. A WEAK COLD FRONT WILL DRIFT SOUTHWARD AND DISSIPATE OVER THE REGION SUNDAY. HIGH PRESSURE WILL REGAIN CONTROL THROUGH THE MIDDLE OF NEXT WEEK. TEMPERATURES WILL REMAIN ABOVE NORMAL. && .NEAR TERM /THROUGH TONIGHT/... RADAR CURRENTLY NOT INDICATING RETURNS OVER OUR FA. SATELLITE/SURFACE OBS NOT INDICATING CU YET EITHER. LATEST RUC SOUNDINGS AND SPC MESOANALYSIS PAGE INDICATING SOME LOW LEVEL CAPPING AND NEGATIVE AREA THAT NEEDS TO BE OVERCOME BEFORE ANY CONVECTION DEVELOPS. STILL EXPECTING SCATTERED CONVECTION TO DEVELOP LATER THIS AFTERNOON THOUGH ONCE FORECAST CONVECTIVE TEMPS REACHED AND SOME LIFT ENCOUNTERED ALONG ANY BOUNDARIES. WHAT DOES DEVELOP COULD POTENTIALLY BE STRONG WITH GUSTY WINDS/HAIL POSSIBLE. THUNDERSTORMS WILL DIMINISH DURING THE EVENING AND OVERNIGHT WITH SLIGHT CHANCE POPS AFTER MIDNIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... A WEAK BACK DOOR COLD FRONT IS EXPECTED TO MOVE INTO THE NORTHERN MIDLANDS ON SUNDAY...AND ALTHOUGH QUITE DIFFUSE...MAY BECOME A FOCUS FOR CONVECTION AS LOW LEVEL CONVERGENCE LIKELY ENHANCED. AIR MASS WILL BE WEAKLY TO MODERATELY UNSTABLE WITH PRECIPITABLE WATER OVER AN INCH. WILL KEEP CHANCE OF SHOWERS AND THUNDERSTORMS FOR SUNDAY...MAINLY DIURNAL. LARGE SPREAD IN THE POP GUIDANCE AND CONFIDENCE REMAINS SOMEWHAT LOW...BUT WILL CONTINUE WITH GENERALLY CHANCE POPS. TEMPS REMAIN ABOVE NORMAL...OVERNIGHT MINIMUM TEMPERATURES ABOVE GUIDANCE DUE TO BIAS. && .LONG TERM /TUESDAY THROUGH SATURDAY/... UPPER RIDGE AND SURFACE HIGH PRESSURE HOLDS ACROSS THE EASTERN U.S. THROUGH MOST OF THE LONG TERM UNTIL LATE WEEK WHEN UPPER LEVEL LOW PRESSURE SLOWLY APPROACHES FROM THE MISSISSIPPI VALLEY. ANOMALOUSLY HIGH HEIGHTS WITH ABOVE NORMAL TEMPERATURES ARE EXPECTED ACROSS THE REGION. ENSEMBLE POPS ARE AT OR BELOW AVERAGE THROUGH MID WEEK...SO WILL KEEP THE FORECAST MAINLY DRY UNTIL TOWARD END OF PERIOD WHEN UPPER LOW APPROACHES. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS EXPECTED...OUTSIDE ANY SHOWER OR POSSIBLE THUNDERSTORM ACTIVITY THAT MAY DEVELOP LATE THIS AFTERNOON INTO EARLY THIS EVENING. WILL HANDLE WITH VCSH AND CB CLOUD GROUP IN THE TAFS FOR NOW. FOG POTENTIAL FOR LATE TONIGHT/SUNDAY MORNING WILL BE DEPENDENT ON CLOUD COVER. SINCE CONFIDENCE LIMITED AT THIS TIME...WILL NOT MENTION FOG. EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS MAY OCCUR IN LATE NIGHT/MORNING FOG THROUGH EARLY NEXT WEEK. SCATTERED AFTERNOON SHOWERS OR A POSSIBLE THUNDERSTORM SUNDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1233 PM CDT SAT MAR 17 2012 .DISCUSSION... ISSUED 1031 AM CDT SAT MAR 17 2012 FOG HAS BEEN SLOW TO DISSIPATE ACROSS CENTRAL ILLINOIS THIS MORNING...WITH 15Z SATELLITE IMAGERY/SURFACE OBS INDICATING FOG/LOW OVERCAST PERSISTING BETWEEN THE ILLINOIS RIVER VALLEY AND THE I-55 CORRIDOR. VISBYS ARE NOW RAPIDLY IMPROVING...SO FOG SHOULD NO LONGER BE AN ISSUE BY MIDDAY. MID-LEVEL SHORT-WAVE EVIDENT ON WATER VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL BE THE MAIN WEATHER-MAKER THIS AFTERNOON. THIS FEATURE IS EXPECTED TO INTERACT WITH A VERY MOIST AND INCREASINGLY UNSTABLE AIRMASS TO PRODUCE SCATTERED THUNDERSTORMS ACROSS THE AREA. LATEST RADAR MOSAIC IS ALREADY SHOWING CONVECTION DEVELOPING AHEAD OF THE WAVE FROM CENTRAL MISSOURI SOUTHEASTWARD INTO WESTERN KENTUCKY. 12Z HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION AND SHOWS THE CONVECTION TRACKING INTO CENTRAL ILLINOIS AFTER 18Z. BASED ON LATEST TRENDS...HAVE MADE A FEW CHANGES TO THE FORECAST...MAINLY TO INCREASE POPS INTO THE LIKELY CATEGORY ACROSS THE S/SW KILX CWA. HAVE ALSO LOWERED AFTERNOON HIGHS BY A FEW DEGREES DUE TO THE EXPECTED INCREASE IN CONVECTION. READINGS WILL STILL REACH THE 80 DEGREE MARK ALONG/NORTH OF THE I-74 CORRIDOR...BUT SHOULD STAY IN THE 70S FURTHER S/SW DUE TO CLOUDS/PRECIP. && .AVIATION... ISSUED 1233 PM CDT SAT MAR 17 2012 MID-LEVEL WAVE CURRENTLY LIFTING NORTHEASTWARD INTO MISSOURI WILL TRIGGER SCATTERED THUNDERSTORMS ACROSS CENTRAL ILLINOIS LATER THIS AFTERNOON AND EVENING. BASED ON RADAR TIMING TOOLS...CONVECTION AROUND KCOU WILL ARRIVE AT KSPI BETWEEN 21 AND 22Z. DUE TO UNCERTAINTIES ASSOCIATED WITH CONVECTIVE DEVELOPMENT/LIFE CYCLE...HAVE OPTED TO MAINTAIN VCTS AT THE TAF SITES UNTIL RADAR TRENDS DICTATE PREDOMINANT THUNDER. USING RADAR DATA AND HRRR/NAM FORECAST...HAVE GIVEN ALL TERMINALS A 4 TO 6 HOUR WINDOW FOR POTENTIAL THUNDER BETWEEN 21Z AND 05Z. AFTER THAT...BEST FOCUS FOR ADDITIONAL THUNDER SHIFTS FURTHER NORTH/EAST OUT OF THE AREA. WINDS WILL BE FROM THE SOUTH THIS AFTERNOON AND MAY GUST TO BETWEEN 15 AND 20KT AS MIXING OCCURS. GUSTINESS WILL SUBSIDE THIS EVENING...WITH S/SW WINDS AT AROUND 10KT CONTINUING INTO SUNDAY MORNING. BARNES && .PREV DISCUSSION... ISSUED 330 AM CDT SAT MAR 17 2012 SHORT TERM...TODAY THROUGH TUESDAY UNSEASONABLY WARM WEATHER STILL EXPECTED TO CONTINUE THROUGH AT LEAST TUE WITH MORE RECORD HIGHS POSSIBLY TIED OR BROKEN. CONVECTION CHANCES IS THE FORECAST CHALLENGE NEXT SEVERAL DAYS. SHORT WAVE EJECTING NE TOWARD IL/MO BORDER BY SUNSET WILL INCREASE CHANCES OF SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON ESPECIALLY SOUTH OF I-72 AND CONTINUE CHANCES TONIGHT. SPC KEEPS SLIGHT RISK OF SEVERE STORMS OVER FAR SOUTHERN IL INTO SE MO... NORTHERN AR AND WESTERN PARTS OF KY/TN. ISOLATED SHOWERS AND THUNDERSTORMS RECENTLY DEVELOPED OVER NW IL/SW WI NORTH OF I-80 AND WEST OF I-39 AND DRIFTING NE AWAY FROM CENTRAL IL. PATCHY FOG DEVELOPING OVER SOUTHEAST IL ALONG HIGHWAY 50 WITH LAWRENCEVILLE VSBY DOWN TO 1/2 MILE. MAY NEED TO ADD PATCHY FOG INTO MID MORNING OVER AREAS SE OF I-70. NEAR RECORD HIGHS AROUND 80F ON THIS ST PATRICKS DAY AND RECORD HIGHS LIKELY IN THE LOWER 80S SUNDAY WITH JUST A 20-30% CHANCE OF SHOWERS AND THUNDERSTORMS OVER EASTERN IL SUNDAY MORNING WITH MOSTLY CLOUDY SKIES BECOMING PARTLY TO MOSTLY SUNNY SUNDAY AFTERNOON AS SHORT WAVE DEPARTS IL. DRY CONDITIONS EXPECTED SUNDAY NIGHT. DEEPENING UPPER LEVEL TROF OVER THE ROCKIES EARLY NEXT WEEK WITH STRONG UPPER LEVEL RIDGE OVER THE EASTERN STATES. THIS TO CONTINUE UNSEASONABLY WARM HIGHS IN THE UPPER 70S AND LOWER 80S MON/TUE WITH MORE RECORD HIGHS LIKELY TIED OR BROKEN. HAVE 20-30% CHANCE OF SHOWERS/THUNDERSTORMS MON-TUE WEST OF I-55 CLOSER TO UPPER LEVEL TROF AND EJECTING SHORT WAVES OVER THE GREAT PLAINS AND TOWARD THE MS VALLEY. EASTERN IL SHOULD GENERALLY STAY DRY AND WARM DURING THIS TIME. SPC HAS SLIGHT RISK OF SEVERE STORMS WEST OF IL MON AND MON NIGHT WHERE BETTER CHANCES OF THUNDERSTORMS WILL BE. LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE FROM WEST TO EAST FROM TUE NIGHT THROUGH THU AS STRONG UPPER LEVEL TROF/LOW SHIFTS EAST TOWARD THE MS VALLEY. HAVE LIKELY POPS OVER FAR WESTERN AREAS TUE NIGHT AND INTO WESTERN AND SW AREAS BY WED NIGHT FROM PEORIA TO TAYLORVILLE WEST. UPPER LEVEL TROF/LOW TO BE NEAR IL THU WITH COOLER WEATHER AND CONTINUE CHANCES OF SHOWERS AND POSSIBLE THUNDERSTORMS. UPPER LEVEL TROF/LOW SHIFTS EAST OF IL FRI WITH BEST CHANCE OF SHOWERS/THUNDERSTORMS SHIFTING EAST OF IL INTO INDIANA AND TEMPS COOLER FURTHER LATE NEXT WEEK. HUETTL && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1031 AM CDT SAT MAR 17 2012 .DISCUSSION... ISSUED 1031 AM CDT SAT MAR 17 2012 FOG HAS BEEN SLOW TO DISSIPATE ACROSS CENTRAL ILLINOIS THIS MORNING...WITH 15Z SATELLITE IMAGERY/SURFACE OBS INDICATING FOG/LOW OVERCAST PERSISTING BETWEEN THE ILLINOIS RIVER VALLEY AND THE I-55 CORRIDOR. VISBYS ARE NOW RAPIDLY IMPROVING...SO FOG SHOULD NO LONGER BE AN ISSUE BY MIDDAY. MID-LEVEL SHORT-WAVE EVIDENT ON WATER VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL BE THE MAIN WEATHER-MAKER THIS AFTERNOON. THIS FEATURE IS EXPECTED TO INTERACT WITH A VERY MOIST AND INCREASINGLY UNSTABLE AIRMASS TO PRODUCE SCATTERED THUNDERSTORMS ACROSS THE AREA. LATEST RADAR MOSAIC IS ALREADY SHOWING CONVECTION DEVELOPING AHEAD OF THE WAVE FROM CENTRAL MISSOURI SOUTHEASTWARD INTO WESTERN KENTUCKY. 12Z HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION AND SHOWS THE CONVECTION TRACKING INTO CENTRAL ILLINOIS AFTER 18Z. BASED ON LATEST TRENDS...HAVE MADE A FEW CHANGES TO THE FORECAST...MAINLY TO INCREASE POPS INTO THE LIKELY CATEGORY ACROSS THE S/SW KILX CWA. HAVE ALSO LOWERED AFTERNOON HIGHS BY A FEW DEGREES DUE TO THE EXPECTED INCREASE IN CONVECTION. READINGS WILL STILL REACH THE 80 DEGREE MARK ALONG/NORTH OF THE I-74 CORRIDOR...BUT SHOULD STAY IN THE 70S FURTHER S/SW DUE TO CLOUDS/PRECIP. BARNES && .AVIATION... ISSUED 656 AM CDT SAT MAR 17 2012 AVIATION WEATHER CONDITIONS ACROSS THE CENTRAL ILLINOIS TERMINALS WILL BE SIMILAR TO HOW THEY HAVE BEEN THE PAST FEW DAYS...WHICH IS TO SAY PRETTY QUIET FOR THE MOST PART. HOWEVER...PATCHY IFR STRATUS/FOG WILL IMPACT AT LEAST KSPI/KDEC/KCMI TERMINALS FOR A FEW HOURS THIS MORNING BEFORE BURNING OFF. THEN...VFR CIGS WILL DEVELOP LATER TODAY AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE AREA...HELPING TO TRIGGER SCATTERED THUNDERSTORMS. HOWEVER... THE COVERAGE IS EXPECTED TO BE TOO LOW TO GO ABOVE A VCTS MENTION AT THIS TIME. THE LOWER CLOUDS WILL SCATTER OUT LATER TONIGHT AS THE UPPER LEVEL SYSTEM PULLS AWAY. EXPECT WINDS TO REMAIN SOUTHERLY...WITH THE HIGHEST SPEEDS AND A FEW GUSTS LIKELY DURING THE PEAK MIXING OF THE AFTERNOON AND EARLY EVENING HOURS TODAY. BAK && .PREV DISCUSSION... ISSUED 330 AM CDT SAT MAR 17 2012 SHORT TERM...TODAY THROUGH TUESDAY UNSEASONABLY WARM WEATHER STILL EXPECTED TO CONTINUE THROUGH AT LEAST TUE WITH MORE RECORD HIGHS POSSIBLY TIED OR BROKEN. CONVECTION CHANCES IS THE FORECAST CHALLENGE NEXT SEVERAL DAYS. SHORT WAVE EJECTING NE TOWARD IL/MO BORDER BY SUNSET WILL INCREASE CHANCES OF SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON ESPECIALLY SOUTH OF I-72 AND CONTINUE CHANCES TONIGHT. SPC KEEPS SLIGHT RISK OF SEVERE STORMS OVER FAR SOUTHERN IL INTO SE MO... NORTHERN AR AND WESTERN PARTS OF KY/TN. ISOLATED SHOWERS AND THUNDERSTORMS RECENTLY DEVELOPED OVER NW IL/SW WI NORTH OF I-80 AND WEST OF I-39 AND DRIFTING NE AWAY FROM CENTRAL IL. PATCHY FOG DEVELOPING OVER SOUTHEAST IL ALONG HIGHWAY 50 WITH LAWRENCEVILLE VSBY DOWN TO 1/2 MILE. MAY NEED TO ADD PATCHY FOG INTO MID MORNING OVER AREAS SE OF I-70. NEAR RECORD HIGHS AROUND 80F ON THIS ST PATRICKS DAY AND RECORD HIGHS LIKELY IN THE LOWER 80S SUNDAY WITH JUST A 20-30% CHANCE OF SHOWERS AND THUNDERSTORMS OVER EASTERN IL SUNDAY MORNING WITH MOSTLY CLOUDY SKIES BECOMING PARTLY TO MOSTLY SUNNY SUNDAY AFTERNOON AS SHORT WAVE DEPARTS IL. DRY CONDITIONS EXPECTED SUNDAY NIGHT. DEEPENING UPPER LEVEL TROF OVER THE ROCKIES EARLY NEXT WEEK WITH STRONG UPPER LEVEL RIDGE OVER THE EASTERN STATES. THIS TO CONTINUE UNSEASONABLY WARM HIGHS IN THE UPPER 70S AND LOWER 80S MON/TUE WITH MORE RECORD HIGHS LIKELY TIED OR BROKEN. HAVE 20-30% CHANCE OF SHOWERS/THUNDERSTORMS MON-TUE WEST OF I-55 CLOSER TO UPPER LEVEL TROF AND EJECTING SHORT WAVES OVER THE GREAT PLAINS AND TOWARD THE MS VALLEY. EASTERN IL SHOULD GENERALLY STAY DRY AND WARM DURING THIS TIME. SPC HAS SLIGHT RISK OF SEVERE STORMS WEST OF IL MON AND MON NIGHT WHERE BETTER CHANCES OF THUNDERSTORMS WILL BE. LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE FROM WEST TO EAST FROM TUE NIGHT THROUGH THU AS STRONG UPPER LEVEL TROF/LOW SHIFTS EAST TOWARD THE MS VALLEY. HAVE LIKELY POPS OVER FAR WESTERN AREAS TUE NIGHT AND INTO WESTERN AND SW AREAS BY WED NIGHT FROM PEORIA TO TAYLORVILLE WEST. UPPER LEVEL TROF/LOW TO BE NEAR IL THU WITH COOLER WEATHER AND CONTINUE CHANCES OF SHOWERS AND POSSIBLE THUNDERSTORMS. UPPER LEVEL TROF/LOW SHIFTS EAST OF IL FRI WITH BEST CHANCE OF SHOWERS/THUNDERSTORMS SHIFTING EAST OF IL INTO INDIANA AND TEMPS COOLER FURTHER LATE NEXT WEEK. HUETTL && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS JACKSON KY
435 PM EDT SAT MAR 17 2012 .UPDATE... ISSUED AT 435 PM EDT SAT MAR 17 2012 SFC BASED INSTABILITY STILL INCREASING OVER THE AREA TO THE POINT OF LOOKING AT A FEW...SHORT LIVED...ISOLATED SHOWERS POPPING AROUND NERN KY WITH NO LIGHTNING ATTM. MORE ROBUST ACTIVITY OVER NRN/CENTRAL TN WOULD BE MOVING INTO OUR CUMBERLAND COUNTIES IN THE NEXT FEW HOURS WHERE LAPS AND SPC MESO ANALYSIS SHOWS SBCAPE CLIMBING TO AROUND 2-3K. GIVEN THE WEAK KINEMATIC FIELDS...NOT EXPECTING ANYTHING TOO STRONG BUT SLOW MOVING HEAVY RAINERS COULD POSE SOME SHORT TERM HYDRO PROBLEMS LATER THIS EVENING. WILL DEFINITELY KEEP A CLOSE EYE ON THIS ACTIVITY AND UPDATE PRIOR TO 00Z IF NECESSARY. OTW...THE CURRENT FORECAST APPEARS TO HAVE A GOOD HANDLE ON THE SITUATION AND NO MAJOR CHANGES ARE NEEDED ATTM. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 351 PM EDT SAT MAR 17 2012 CURRENT CONDITIONS ACROSS THE AREA AS OF 19Z HAS A ROBUST CU FIELD DEVELOPING OVER CENTRAL KENTUCKY EXTENDING INTO THE BLUE GRASS COUNTIES AND ALONG THE I-75 CORRIDOR. SO FAR TODAY...ONLY A FEW SHOWERS HAVE DEVELOPED AND JUDGING BY WHATS GOING ON UPSTREAM...THE WEAK WAVE PICKED OUT IN THE RUC AND SREF...HAS ONLY BEEN ABLE TO GEN UP A FEW SHOWERS. IT SEEMS WE WILL HAVE TO WAIT TILL TONIGHT FOR THE STRONGER WAVE OUT IN WESTERN KENTUCKY TO MOVE INTO THE OUR CWFA TO PRODUCE ANY SHOWERS AND THUNDERSTORMS. BY THIS POINT...THE INSTABILITY TO WORK WITH FROM THE DAY WILL HAVE BEEN PRETTY MUCH CUT OFF SO EXPECTING JUST SOME RUN OF THE MILL SHOWERS AND THUNDERSTORMS THIS EVENING AND TONIGHT. WITH AMPLE MOISTURE FROM THE GULF CONTINUING...THE WAVE MOVING THROUGH TONIGHT WILL PRODUCE THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH SUNDAY NIGHT. WATER VAPOR ALSO HINTED AT A STRONG MOISTURE FLUX IN FROM THE BAJA REGION WITH A FEW EMBEDDED WAVES AND THEREFORE A PROLONGED PERIOD OF PERIODIC SHOWER AND THUNDERSTORM ACTIVITY THROUGH SUNDAY NIGHT SEEMS LIKELY. BY DAYTIME HEATING FOR SUNDAY...SHOWER AND THUNDERSTORM ACTIVITY SHOULD PERSIST. AT THIS POINT...DUE TO THE INCH AND A TENTH PWATS...THINKING THAT RAINFALL DURING THIS PERIOD WILL BE THE ONLY FACTOR TO MONITOR CLOSELY. THE CONTINUED CLOUD COVER OVER THE AREA WILL KEEP THE THREAT OF STRONG STORMS IN CHECK BUT STORMS WITH HEAVY RAINFALL WILL STILL BE POSSIBLE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 351 PM EDT SAT MAR 17 2012 THE MODELS BEGIN THE EXTENDED PORTION OF THE FORECAST IN DECENT AGREEMENT ALOFT. THEY ALL HAVE THE FULL LATITUDE WESTERN TROUGH DESCENDING AND DEEPENING INTO A CUT OFF LOW OVER NORTHERN TEXAS DURING THE DAY TUESDAY. THIS RESULTS IN A STRONG DOWNSTREAM RIDGE BUILDING OVER THE APPALACHIANS FROM MONDAY INTO TUESDAY NIGHT. AROUND THIS TIME...THOUGH...THE MODELS START TO DIVERGE FROM EACH OTHER WITH RESPECT TO THE THIS KEY FEATURE. THE ECMWF AND GEM MOVE THE LOW EASTWARD QUICKER THAN THE GFS AND THIS DIFFERENCE CONTINUES INTO THE DAY THURSDAY AS IT PIVOTS OVER THE MID MISSISSIPPI VALLEY AND STARTS TO ENCROACH ON THE OHIO AND TENNESSEE VALLEYS. BY THIS TIME THE WEAKER ECMWF IS ABOUT 200 MILES EAST OF THE GFS AND THE GEM ABOUT THE SAME DISTANCE TO THE SOUTHEAST. GIVEN THE MID LEVEL JET RUNNING SOUTHWEST TO NORTHEAST THROUGH THE MIDDLE OF THE CONTINENT...PREFER THE SLOWER GFS IN THIS CUTOFF FAVORING FLOW PATTERN. AS THE UPPER LOW SLOWLY CROSSES THE MISSISSIPPI RIVER AND MOVES OVER WESTERN TENNESSEE AND KENTUCKY...THE ECMWF WILL START TO RETROGRADE. AS A RESULT...BY FRIDAY EVENING THEY HAVE A SIMILAR MAGNITUDE AND PLACEMENT FOR THE LOW...PRETTY MUCH CENTERED OVER EAST KENTUCKY. FURTHER NORTH...THOUGH...THEY DIFFER ON THE MAGNITUDE OF A TROUGH IN THE JET STREAM SO THAT EVEN THE SIMILARITIES OVER OUR AREA TO END THE WEEK DOES NOT ENHANCE CONFIDENCE. THE MODELS THEN TAKE THE REMAINS OF THEIR LOWS SLOWLY EAST THROUGH THE APPALACHIANS AND TO THE EAST COAST...AS RIDGING BUILDS INTO THE PLAINS. DUE TO LOW CONFIDENCE WITH HOW THE UPPER LOW IS FINALLY KICKED OUT OF THE REGION WILL DOWN PLAY THIS POTENTIAL FOR NOW. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR RECENT HEAT WAVE. THERE WILL BE A LULL IN THE SHOWERS AND STORMS OF THE PAST FEW DAYS ON MONDAY AS THE UPPER RIDGE BUILDS ENOUGH TO CAP SUPPRESS ANY CONVECTION AND SFC HIGH PRESSURE DRIES OUT THE AIR MASS A BIT. EAST KENTUCKY WILL REMAIN BETWEEN WEATHER SYSTEMS THROUGH WEDNESDAY AS A BAND OF CONVECTION ASSOCIATED WITH THE STACKED LOW AND ITS OCCLUDED FRONT SLOWLY MOVE DEEPER INTO KENTUCKY. THE WARM WEATHER THAT PRECEDED THE FRONT WILL HAVE ITS LAST HURRAH ON WEDNESDAY BEFORE THE MATURE LOW...ITS OCCLUDED COLD SECTOR...AND RENEWED RAINS WILL COMBINE TO RETURN US TO TEMPERATURES CLOSER TO NORMAL FOR THIS TIME OF YEAR AT THE END OF THE WORK WEEK AND TO START THE WEEKEND. THE BEST CONVECTIVE THREAT LOOKS TO BE THURSDAY AND INTO FRIDAY MORNING AS THAT BOUNDARY MOVES INTO THE AREA. THIS WILL ALSO BE THE PEAK TIME FOR EXCESSIVE RAINFALL...AS WELL. ONCE THE FRONT PASSES THROUGH THE AREA...JUST THE SHOWERS AND STRAY THUNDERSTORMS TYPICALLY FOUND SCATTERED AROUND THE CENTER OF A MATURE LOW CAN BE EXPECTED THROUGH THE DAY FRIDAY AND INTO SATURDAY. THE GRID LOAD CAME IN REASONABLE ENOUGH CONSIDERING THE SLUGGISH MOVEMENT OF THE SFC FEATURES TO AFFECT THE AREA THROUGH THE PERIOD. DID FINE TUNE THE POPS FOR A SLOWER ARRIVAL ON THURSDAY... ESPECIALLY IN THE EAST. PUT A DIURNAL COMPONENT INTO THE POP GRIDS THROUGH THE LATTER PART OF THE EXTENDED. ALSO...RAISED MAX TEMPS A BIT FOR MONDAY THROUGH WEDNESDAY AND ADDED MINOR TERRAIN BASED ADJUSTMENTS BENEATH THAT BUILDING RIDGE EACH NIGHT FROM MONDAY NIGHT THROUGH WEDNESDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 130 PM EDT SAT MAR 17 2012 VRF CONDITIONS...WEAK LOW LEVEL FLOW...AND ONLY SOME CEILINGS AROUND 5 KFT AND 10 KFT WILL PERSIST THROUGH THE DAY. A STRAY SHOWER IS POSSIBLE BUT OVERALL...THIS SHOULD BE A QUIET DAY AVIATION WISE. SOME MVFR CONDITIONS WILL DEVELOP AFTER 02Z AS A STRONGER WAVE MOVES THROUGH THE AREA TONIGHT. SOME SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AND SHOULD PERSIST THROUGH 06Z. VFR CONDITIONS WILL RETURN BY 15Z TOMORROW. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MB SHORT TERM...SHALLENBERGER LONG TERM....GREIF AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
351 PM EDT SAT MAR 17 2012 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 351 PM EDT SAT MAR 17 2012 CURRENT CONDITIONS ACROSS THE AREA AS OF 19Z HAS A ROBUST CU FIELD DEVELOPING OVER CENTRAL KENTUCKY EXTENDING INTO THE BLUE GRASS COUNTIES AND ALONG THE I-75 CORRIDOR. SO FAR TODAY...ONLY A FEW SHOWERS HAVE DEVELOPED AND JUDGING BY WHATS GOING ON UPSTREAM...THE WEAK WAVE PICKED OUT IN THE RUC AND SREF...HAS ONLY BEEN ABLE TO GEN UP A FEW SHOWERS. IT SEEMS WE WILL HAVE TO WAIT TILL TONIGHT FOR THE STRONGER WAVE OUT IN WESTERN KENTUCKY TO MOVE INTO THE OUR CWFA TO PRODUCE ANY SHOWERS AND THUNDERSTORMS. BY THIS POINT...THE INSTABILITY TO WORK WITH FROM THE DAY WILL HAVE BEEN PRETTY MUCH CUT OFF SO EXPECTING JUST SOME RUN OF THE MILL SHOWERS AND THUNDERSTORMS THIS EVENING AND TONIGHT. WITH AMPLE MOISTURE FROM THE GULF CONTINUING...THE WAVE MOVING THROUGH TONIGHT WILL PRODUCE THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH SUNDAY NIGHT. WATER VAPOR ALSO HINTED AT A STRONG MOISTURE FLUX IN FROM THE BAJA REGION WITH A FEW EMBEDDED WAVES AND THEREFORE A PROLONGED PERIOD OF PERIODIC SHOWER AND THUNDERSTORM ACTIVITY THROUGH SUNDAY NIGHT SEEMS LIKELY. BY DAYTIME HEATING FOR SUNDAY...SHOWER AND THUNDERSTORM ACTIVITY SHOULD PERSIST. AT THIS POINT...DUE TO THE INCH AND A TENTH PWATS...THINKING THAT RAINFALL DURING THIS PERIOD WILL BE THE ONLY FACTOR TO MONITOR CLOSELY. THE CONTINUED CLOUD COVER OVER THE AREA WILL KEEP THE THREAT OF STRONG STORMS IN CHECK BUT STORMS WITH HEAVY RAINFALL WILL STILL BE POSSIBLE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 351 PM EDT SAT MAR 17 2012 THE MODELS BEGIN THE EXTENDED PORTION OF THE FORECAST IN DECENT AGREEMENT ALOFT. THEY ALL HAVE THE FULL LATITUDE WESTERN TROUGH DESCENDING AND DEEPENING INTO A CUT OFF LOW OVER NORTHERN TEXAS DURING THE DAY TUESDAY. THIS RESULTS IN A STRONG DOWNSTREAM RIDGE BUILDING OVER THE APPALACHIANS FROM MONDAY INTO TUESDAY NIGHT. AROUND THIS TIME...THOUGH...THE MODELS START TO DIVERGE FROM EACH OTHER WITH RESPECT TO THE THIS KEY FEATURE. THE ECMWF AND GEM MOVE THE LOW EASTWARD QUICKER THAN THE GFS AND THIS DIFFERENCE CONTINUES INTO THE DAY THURSDAY AS IT PIVOTS OVER THE MID MISSISSIPPI VALLEY AND STARTS TO ENCROACH ON THE OHIO AND TENNESSEE VALLEYS. BY THIS TIME THE WEAKER ECMWF IS ABOUT 200 MILES EAST OF THE GFS AND THE GEM ABOUT THE SAME DISTANCE TO THE SOUTHEAST. GIVEN THE MID LEVEL JET RUNNING SOUTHWEST TO NORTHEAST THROUGH THE MIDDLE OF THE CONTINENT...PREFER THE SLOWER GFS IN THIS CUTOFF FAVORING FLOW PATTERN. AS THE UPPER LOW SLOWLY CROSSES THE MISSISSIPPI RIVER AND MOVES OVER WESTERN TENNESSEE AND KENTUCKY...THE ECMWF WILL START TO RETROGRADE. AS A RESULT...BY FRIDAY EVENING THEY HAVE A SIMILAR MAGNITUDE AND PLACEMENT FOR THE LOW...PRETTY MUCH CENTERED OVER EAST KENTUCKY. FURTHER NORTH...THOUGH...THEY DIFFER ON THE MAGNITUDE OF A TROUGH IN THE JET STREAM SO THAT EVEN THE SIMILARITIES OVER OUR AREA TO END THE WEEK DOES NOT ENHANCE CONFIDENCE. THE MODELS THEN TAKE THE REMAINS OF THEIR LOWS SLOWLY EAST THROUGH THE APPALACHIANS AND TO THE EAST COAST...AS RIDGING BUILDS INTO THE PLAINS. DUE TO LOW CONFIDENCE WITH HOW THE UPPER LOW IS FINALLY KICKED OUT OF THE REGION WILL DOWN PLAY THIS POTENTIAL FOR NOW. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR RECENT HEAT WAVE. THERE WILL BE A LULL IN THE SHOWERS AND STORMS OF THE PAST FEW DAYS ON MONDAY AS THE UPPER RIDGE BUILDS ENOUGH TO CAP SUPPRESS ANY CONVECTION AND SFC HIGH PRESSURE DRIES OUT THE AIR MASS A BIT. EAST KENTUCKY WILL REMAIN BETWEEN WEATHER SYSTEMS THROUGH WEDNESDAY AS A BAND OF CONVECTION ASSOCIATED WITH THE STACKED LOW AND ITS OCCLUDED FRONT SLOWLY MOVE DEEPER INTO KENTUCKY. THE WARM WEATHER THAT PRECEDED THE FRONT WILL HAVE ITS LAST HURRAH ON WEDNESDAY BEFORE THE MATURE LOW...ITS OCCLUDED COLD SECTOR...AND RENEWED RAINS WILL COMBINE TO RETURN US TO TEMPERATURES CLOSER TO NORMAL FOR THIS TIME OF YEAR AT THE END OF THE WORK WEEK AND TO START THE WEEKEND. THE BEST CONVECTIVE THREAT LOOKS TO BE THURSDAY AND INTO FRIDAY MORNING AS THAT BOUNDARY MOVES INTO THE AREA. THIS WILL ALSO BE THE PEAK TIME FOR EXCESSIVE RAINFALL...AS WELL. ONCE THE FRONT PASSES THROUGH THE AREA...JUST THE SHOWERS AND STRAY THUNDERSTORMS TYPICALLY FOUND SCATTERED AROUND THE CENTER OF A MATURE LOW CAN BE EXPECTED THROUGH THE DAY FRIDAY AND INTO SATURDAY. THE GRID LOAD CAME IN REASONABLE ENOUGH CONSIDERING THE SLUGGISH MOVEMENT OF THE SFC FEATURES TO AFFECT THE AREA THROUGH THE PERIOD. DID FINE TUNE THE POPS FOR A SLOWER ARRIVAL ON THURSDAY... ESPECIALLY IN THE EAST. PUT A DIURNAL COMPONENT INTO THE POP GRIDS THROUGH THE LATTER PART OF THE EXTENDED. ALSO...RAISED MAX TEMPS A BIT FOR MONDAY THROUGH WEDNESDAY AND ADDED MINOR TERRAIN BASED ADJUSTMENTS BENEATH THAT BUILDING RIDGE EACH NIGHT FROM MONDAY NIGHT THROUGH WEDNESDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 130 PM EDT SAT MAR 17 2012 VRF CONDITIONS...WEAK LOW LEVEL FLOW...AND ONLY SOME CEILINGS AROUND 5 KFT AND 10 KFT WILL PERSIST THROUGH THE DAY. A STRAY SHOWER IS POSSIBLE BUT OVERALL...THIS SHOULD BE A QUIET DAY AVIATION WISE. SOME MVFR CONDITIONS WILL DEVELOP AFTER 02Z AS A STRONGER WAVE MOVES THROUGH THE AREA TONIGHT. SOME SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AND SHOULD PERSIST THROUGH 06Z. VFR CONDITIONS WILL RETURN BY 15Z TOMORROW. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SHALLENBERGER LONG TERM....GREIF AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
101 AM EDT SAT MAR 17 2012 .Update... Issued at 945 PM EDT Fri Mar 16 2012 Have updated grids to mainly reflect latest position of scattered to numerous showers across south central Kentucky associated with MCV. Saw a lightning strike or two with the strongest updrafts earlier this evening so will leave mention of isolated thunder in the forecast. On an otherwise quiet evening, a few of the cells near the Bowling Green region put on quite a show, displaying supercell characteristics at times. Storms developed on a north south oriented boundary across west central Kentucky and Tennessee, then maintained sustained updrafts with deviant (right-moving) motion near Bowling Green. Weak rotation was maintained on radar, with a spotter observing weak rotation at times. How these cells were able to maintain updrafts without any organized deep shear remains a mystery. Showers associated with the MCV will slide across south central Kentucky for the next few hours with only an isolated chance elsewhere across the CWA. Still remains some question as to how the overnight period will go with respect to weak isentropic lift component across western CWA between 06-12Z so will just mention isolated chances, however do expect coverage of precipitation to gradually increase from southwest to northeast after 12Z. Best chance for showers and thunderstorms still looks to be tomorrow afternoon and evening as a shortwave moves through the region from the southwest. Forecast looks on track, with skies generally becoming partly cloudy through the overnight. Will have to watch for fog potential as recent rainfall combines with improving radiational cooling conditions as skies clear and winds remain light and variable. Tweaked lows down just a bit with most spots in the upper 50s and a few locations hanging on around 60. Updated products already out. Update issued at 654 PM EDT Fri Mar 16 2012 Showers have developed over the west central portion of the CWA with MCV that is slowly rotating through western Kentucky. A look at forecast soundings shows that updrafts should struggle above 15-20 K feet as thermal profile warms significantly above this level. Do not expect much more than a few moderate showers mainly across central Kentucky, although cannot rule out an isolated thunderstorm or two. Have tweaked pops just a bit through the overnight hours with the potential for a scattered line of mainly showers to develop over the Bowling Green region and lift northeastward from 06 to 12z. Models disagree on the timing with NAM/GFS more toward dawn, however higher res HRRR which has current situation handled well begins precip just after 06 z. The main culprit appears to be some weak isentropic lift with a weak low level jet. Will monitor trends and update timing as needed. Otherwise, the rest of the forecast looks on track at this point. .Short Term (Tonight through Saturday Night)... Updated at 255 PM EDT Mar 16 2012 Meso low continues to spin just to our west, now with a surface reflection in latest MSAS analysis. Fortunately for us, persistent cloud cover for most of the day so far has inhibited convection over our CWA. Western Kentucky has been clearer though, and that area now is seeing some convections, with cells initiating over eastern PAH`s forecast area. Temperatures are climbing over the western forecast area, so should start seeing some action there a little later this afternoon, especially as that low drifts eastward. Beyond this afternoon and through Saturday night, the atmosphere will remain plenty moist for additional shower and storm development. Confidence in timing/location still is not high though. Precipitable waters will be above an inch. Will have multiple perturbations in the flow aloft coming across the region, which will enhance development, especially should these come during any peak heating times. Given the moist atmosphere, diurnal temperature swings should be short, and expect readings well above normal for mid March. Going for lows each night around 60 and highs generally in the upper 70s. .Long Term (Sunday - Friday)... Updated at 255 PM EDT Mar 16 2012 For Sunday, another shortwave in the upper level flow will cross the Ohio Valley. The models are still having a bit of a hard time with the timing and the placement of this feature. This will impact how widespread storms become on Sunday. For now we will continue to carry a 30-40% chance for thunderstorms. Soundings do become relatively unstable during the day so a few of these storms may become strong. These will be the pulse type like we have seen the last couple of days, with hail being the main threat. For the beginning of the work week, a highly amplified ridge will build over the area. This will lead to partly cloudy skies and dry weather Monday through Tuesday. At the surface, winds will remain out of the south. Unseasonably warm temperatures will continue with a shot at breaking some record highs Sunday through Monday. Current records and forecast temps for Sun/Mon/Tues: ASOS Sun(3/18) Mon(3/19) Tues(3/20) Record/Forecast: SDF 82(1982)/81 83(1907)/83 85(1894)/82 LEX 79(1982)/79 79(1945)/81 81(1894)/81 BWG 87(1908)/82 86(1907)/83 85(1921)/82 FFT 80(1908)/80 81(1948)/82 82(1921)/81 We will see a big change in the weather for the second half of the week. A large upper level low will approach and cross the region Wednesday through Friday. Clouds will be on the increase on Wednesday, keeping temperatures a few degrees cooler than the previous days. Rain from this system looks to move in Wednesday night with showers and thunderstorms continuing into Friday as the low slowly crosses the region. Temperatures will be much cooler Thursday and Friday. Despite this, temps will remain above normal for this time of year with highs in the mid 60s to lower 70s and lows in the upper 40s to lower 50s. && .Aviation (06Z TAF Issuance)... Updated at 100 AM EDT Mar 17 2012 Scattered showers across central Kentucky are slowly moving northeast as a MCV spins over the area. Would anticipate this scattered activity to move near LEX and even perhaps SDF for the next few hours. Could even see areal coverage increasing a bit. Models continue to hint at additional shower development closer to dawn, mainly in the BWG region. Will continue to monitor trends over the next few hours, but upstream cloud cover has diminished. If the clearing trend works into the area as this MCV slowly moves east this morning and there is no more shower redevelopment, then some MVFR BR at all TAF sites will be possible toward dawn. Given the upstream observations/trends, will continue reduced visibility in the forecast. While the additional shower development later this morning remains uncertain, believe the best areal coverage will be with the mid-level wave that will approach the area this afternoon and into the evening hours. Calm or light southeasterly winds this morning will become southwesterly between 5 and 10 mph for the afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........BJS Short Term.......RJS Long Term........EER Aviation.........MJP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1011 PM EDT SUN MAR 18 2012 .SYNOPSIS... A SLOW MOVING EASTBOUND UPPER LEVEL LOW PRESSURE TROUGH WILL BRING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT WITH PATCHY FOG INTO THE EARLY MORNING. SUNSHINE MAY HELP DEVELOP ISOLATED THUNDERSTORMS MONDAY AFTERNOON, AS WARM TEMPERATURES WILL CONTINUE THIS WEEK. && .NEAR TERM /THROUGH MONDAY/... PER BLEND OF RECENT RADAR AND SURFACE DATA ALONG WITH HRRR AND NAM MODEL OUTPUT, MADE ADDITIONAL SMALL ADJUSTMENTS TO THE EASTBOUND MOVEMENT OF A BAND OF SHOWERS AND THUNDERSTORMS OVERNIGHT. THE PRECIPITATION IS ASSOCIATED WITH A LOW PRESSURE TROUGH ALOFT. THE INTENSITY OF THE THUNDERSTORM HAS DECREASED, NO LONGER HAVE MENTION OF GUSTY WINDS OR HAIL. HOWEVER, NOCTURNAL COOLING OF A RAIN- MOISTENED SURFACE LAYER CAN RESULT IN PATCHY FOG OVERNIGHT INTO MONDAY MORNING. CLOUDS WILL ERODE DURING MONDAY MORNING, TO PROVIDE SOME SUNSHINE BY AFTERNOON. THIS MAY GIVE RISE TO ENOUGH INSTABILITY FOR ISOLATED AFTERNOON THUNDERSTORMS. TWEAKED TEMPERATURES USING RECENT HRRR AND GFS LAMP MODEL OUTPUT. THESE SHOW LOWS TONIGHT SIMILAR TO SATURDAY NIGHT, AND HIGHS MONDAY A TAD WARMER THAN SUNDAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... EXPECT SHOWER CHANCES TO DECREASE MONDAY NIGHT WITH NOCTURNAL COOLING OF THE SURFACE LAYER REDUCING INSTABILITY. WITH UPPER LEVEL SHORT-WAVE TROUGH HAVING PAST EAST OF THE MOUNTAINS TUESDAY, HAVE FORECASTED DRY CONDITIONS TUESDAY AND WEDNESDAY. BOTH MAV/MET GUIDANCE HAVE TEMPERATURES REACHING VERY CLOSE TO 80 BY MIDWEEK AND WITH STRONG RIDGE STATIONED TO THE EAST AND SOUTHERLY FLOW...FELT NO REASON TO STRAY FROM THESE NUMBERS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... REGION WILL BE UNDER AN UPPER LEVEL RIDGE INTO THURSDAY WITH MILD TEMPERATURES. THERE MAY BE ENOUGH LOW LEVEL MOISTURE THAT A DIURNAL SHOWER IS POSSIBLE THURSDAY...BUT OVERALL A DRY FORECAST. LARGE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL GRADUALLY COME EAST BY FRIDAY WITH SHOWERS INTO SATURDAY. MODELS HAVE TIMING DIFFERENCES BY THE DAY 7 TIME PERIOD WITH A SHOT OF COLDER AIR MOVING DOWN FROM THE NORTHERN PLAINS BEHIND THE SATURDAY SYSTEM. USED HPC GUIDANCE FOR CONSISTENCY. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... MAIN FORECAST CONCERN WILL BE EASTWARD PASSAGE OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT, THAT CAN RESULT IN MAINLY MVFR CONDITIONS. SUBSEQUENT NIGHTTIME COOLING OF A RAIN-MOISTENED SURFACE LAYER MAY RESULT IN PATCHES OF IFR FOG THROUGH 14Z. AFTER FOG DISSIPATES MONDAY MORNING, EXPECT VFR CONDITIONS FOR THE REMAINDER OF THE DAY. ISOLATED THUNDERSTORMS MAY DEVELOP DURING THE AFTERNOON BUT HAVE LOW CONFIDENCE ANY TAF SITES WILL BE AFFECTED. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... HIGH PRESSURE WILL DOMINATE INTO THURSDAY WITH GENERAL VFR CONDITIONS. SHOWERS AND POSSIBLE RESTRICTIONS WILL RETURN FRIDAY AS A STORM SYSTEM MOVES EAST FROM THE CENTRAL PLAINS STATES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
937 PM EDT SUN MAR 18 2012 .SYNOPSIS... SURFACE HIGH PRESSURE WILL REMAIN CENTERED OFF THE MID ATLANTIC COAST INTO THE LATE PART OF THE WEEK. A SOUTHERLY FLOW AROUND THE HIGH WILL CONTINUE TO BRING UNUSUALLY WARM CONDITIONS FOR THIS TIME OF YEAR FOR THE WORKWEEK. LOW PRESSURE IS EXPECTED APPROACH THE MID- ATLANTIC NEXT WEEKEND. && .NEAR TERM /UNTIL 8 AM MONDAY MORNING/... SHOWERS AND THUNDERSTORMS WEST OF THE BLUE RIDGE HAVE WANED THIS EVENING...WITH EYES NOW ON AN MCS OVER ERN OH PUSHING ESE INTO WV LATE THIS EVENING. AGREE WITH 22Z HRRR THAT THE THUNDERSTORMS SHOULD REACH THE ALLEGHENY FRONT MOSTLY INTACT...AND THAT DOWNSLOPING FLOW AND STABILITY FROM EARLIER SHOWERS SHOULD GREATLY REDUCE THE INTENSITY EAST FROM THERE. THIS ACTIVITY SHOULD STRUGGLE TO MAKE IT TO THE BLUE RIDGE. THE MIDNIGHT SHIFT WILL HAVE TO MONITOR THIS ACTIVITY...WHICH WILL CONTINUE TO PROPAGATE SE AS IT ROUNDS THE RIDGE. EAST OF THE BLUE RIDGE...MOSTLY CLEAR SKIES ARE EXPECTED UNTIL THE DEBRIS FROM THE OH MCS COMES ACROSS LATE TONIGHT. THEREFORE... WITH SFC DEWPOINTS IN THE LOW 50S...EXPECT AREAS OF FOG TO DEVELOP ACROSS THE GREATER BALT- WASH METRO AFTER 3 AM OR SO. && .SHORT TERM /8 AM MONDAY MORNING THROUGH 6 PM MONDAY/... EXPECT FOG TO CONTINUE INTO LATE MONDAY MORNING...ERODING BEFORE NOON IN MOST PLACES. THE ATMOSPHERE OVR THE ERN U.S. ISN`T CHANGING MUCH AS HIGH PRES RMNS OFFSHORE W/ A VERY LARGE UPR TROF DIGGING INTO THE DESERT SW. THIS WL CAUSE A CONTINUANCE OF WARM MOIST AIR FLOWING INTO THE MID ATLC. ONCE AGN THE BEST CHC FOR RW WL BE IN THE FAR WRN SXN OF THE CWA. E OF THE MTNS TMRW MRNG XPCT LO CLDS..FOG..OR BOTH? HOWEVER THE LOW LVL MOISTURE DISPLAYS ITSELF IN THE MRNG IT IS AGN LKLY THAT BY AFTN MUCH OF THE AREA WL BE P SUNNY. HIGH TEMPS 70-75 ACROSS THE RGN. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... THE LARGE-SCALE UPPER RIDGE WILL AMPLIFY OVER THE ERN SEABOARD DURING THE MIDDLE OF THE WEEK. THE CENTER OF THE SFC HIGH WILL REMAIN ANCHORED JUST OFF THE EAST COAST THRU THE REST OF THE WEEK. THIS PATTERN WILL CONTINUE TO SUPPORT UNSEASONABLY WARM CONDITIONS DURING THE LONG-TERM PERIOD. FLOW AROUND THE HIGH WILL INITIALLY PROVIDE AN ONSHORE TRAJECTORY MON NGT THRU WED MRNG. RESULTANT FLOW WILL ADVECT MARINE AIR INLAND...LEADING TO PERIODS OF STRATUS AND FOG EAST OF THE BLUE RIDGE...ESPECIALLY DURING THE NGT AND MRNG TIME EACH DAY. THE BEST DAYTIME HEATING WILL BE ACROSS THE HIGHER TERRAIN ON TUE AS THE STRATUS WILL TAKE TIME TO DISSIPATE DURING THE MRNG. MAX TEMPS TUE WILL RANGE FROM THE MID 60S NEAR THE WRN SHORE OF THE CHSPK BAY TO MID 70S WEST OF THE BLUE RIDGE. A VERY WEAK MID-LVL SHORTWAVE TROUGH EMBEDDED WITHIN THE UPPER RIDGE AND UPSLOPE ELY FLOW MAY PROVIDE ENOUGH LIFT FOR ISO TO PERHAPS SCT SHOWERS ACROSS THE HIGHER TERRAIN TUE AFTN. AN ISO TSTM CANNOT BE RULED OUT AS WELL...BUT WEAK LLVL LAPSE RATES WILL LIMIT MAGNITUDE OF INSTABILITY. THE FLOW WILL VEER OUT OF THE SOUTH BY WED AS THE SFC HIGH SHIFTS OFF THE MID-ATLANTIC COAST. MAX TEMPS DURING THE SECOND HALF OF THE WEEK WILL BE IN THE MID TO UPPER 70S JUST ABOUT EVERYWHERE /WHICH IS 15-20F ABOVE NORMAL/. MAX TEMPS COULD FLIRT WITH THE 80 DEGREES THU AND FRI. IT WILL BE HARD TO BREAK DAILY MAX TEMP RECORDS AT DCA/BWI THIS WEEK...BUT IAD MAY BE EASIER TO REACH MON-WED. THE NEXT DECENT CHANCE FOR APPRECIABLE PRECIPITATION WILL BE THIS WEEKEND AS A CUTOFF LOW OVER THE SRN PLAINS WILL EVENTUALLY EJECT NEWD TOWARD THE EAST COAST THIS WEEKEND. MODEL TREND HAS BEEN TO SLOW DOWN THE SYSTEM...WHICH SEEMS PLAUSIBLE CONSIDERING HOW FAR SOUTH THE CUTOFF LOW WILL BE AND HOW UNSEASONABLY FAR NORTH THE JET STREAM HAS RETREATED DURING THIS WARM PERIOD. THERE IS HIGHER THAN NORMAL SPREAD REGARDING THE TIMING...COVERAGE AND AMOUNT OF PRECIP GIVEN THE COMPLEX NATURE OF THE PATTERN. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... MORE OF A RADIATION FOG CASE THAN ADVECTION FOG TONIGHT WITH MOSTLY CLEAR SKIES FOR TERMINALS EAST OF THE BLUE RIDGE AND NORTH OF KCHO...AND AMPLE SFC MOISTURE /DEWPOINTS IN THE LOW 50S/. MID LEVEL CLOUDS WILL PERSIST WEST OF THE BLUE RIDGE/SOUTH OF DC METRO INTO LATE TONIGHT...WHEN DEBRIS CLOUDS FROM A THUNDERSTORM COMPLEX CURRENTLY OVER OH MOVES SE ACROSS THE CENTRAL MID ATLANTIC. EXPECT IFR VSBYS ACROSS THE AREA INCLUDING KDCA...WITH LIFR AT IAD/BWI AFTER 08Z. IFR CONDITIONS LAST INTO LATE MORNING MONDAY BEFORE BREAKING. MONDAY AFTERNOON SUNSHINE ON THE MOIST SURFACE SHOULD LEAD TO SCATTERED SHOWERS AND THUNDERSTORMS FROM EAST OF THE ALLEGHENY FRONT TO ACROSS THE BALT-WASH METRO. ACTIVITY SHOULD WANE WITH NIGHTFALL. HIPRES WILL REMAIN PARKED OFF THE EAST COAST THRU THE REMAINDER OF THE WEEK. ONSHORE FLOW WILL FAVOR INLAND PROGRESSION OF MARINE LAYER AGAIN MON NGT/TUE MRNG AND POSSIBLY EVEN TUE NGT/WED MRNG. A PERIOD OF IFR CIGS/VSBYS WILL BE POSSIBLE WITHIN MARINE LAYER...ESPECIALLY ACROSS THE ERN TERMINALS. ONSHORE FLOW IS FCST TO END BY WED...BRINGING A PERIOD OF VFR CONDITIONS THRU FRI. A STORM SYSTEM WILL BE ACCOMPANIED BY INCREASING CHANCES FOR PRECIP NEXT WEEKEND. && .MARINE... WITH HIGH CENTERED OFF NJ SHORE...SELY FLOW AROUND 10 KT WILL CONTINUE UP THE TIDAL POTOMAC THIS EVENING...WITH SLY/SELY FLOW UP TO 10 KT REST OF THE MD PORTION OF THE BAY. EXPECT MORE OF THE SAME THROUGH MONDAY...WITH WINDS GENERALLY JUST EAST OF SOUTH. LIGHT E-SE FLOW TUE WILL BECOME SLY WED-FRI. SLY WINDS INCREASE AHEAD OF A STORM SYSTEM THIS WEEKEND. UNTIL THEN...WINDS SHOULD REMAIN BELOW SCA LVLS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...JACKSON PREVIOUS DISCUSSION...ABW/JRK
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
749 PM EDT SUN MAR 18 2012 .SYNOPSIS... A SLOW MOVING EASTBOUND UPPER LEVEL LOW PRESSURE TROUGH WILL BRING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS TONIGHT AND PATCHY FOG IN THE EARLY MORNING, AS WARM TEMPERATURES CONTINUE THIS WEEK. && .NEAR TERM /THROUGH MONDAY/... PER BLEND OF RECENT RADAR AND SURFACE DATA ALONG WITH HRRR AND NAM MODEL OUTPUT, MADE SMALL ADJUSTMENTS TO THE EASTBOUND MOVEMENT OF A BAND OF SHOWERS AND THUNDERSTORMS TONIGHT. THE PRECIPITATION IS ASSOCIATED WITH A LOW PRESSURE TROUGH ALOFT. HAVE ADDED GUSTY WINDS AND HAIL TO THE STORMS AS FAR EAST AS THE I-77 CORRIDOR IN OHIO. EXPECT THUNDERSTORM INTENSITY TO DECREASE FARTHER EAST AFTER 10 PM. WITH RAINFALL OVERNIGHT INTO A SURFACE LAYER WITH DEW POINTS IN THE MID 50S, PATCHY FOG CAN DEVELOP LATE TONIGHT INTO EARLY MONDAY MORNING. CLOUDS WILL ERODE DURING MONDAY TO PROVIDE SOME SUNSHINE BY AFTERNOON. THIS MAY GIVE RISE TO ENOUGH INSTABILITY FOR SCATTERED AFTERNOON THUNDERSTORMS. TWEAKED TEMPERATURES USING RECENT HRRR AND GFS LAMP MODEL OUTPUT. THESE SHOW LOWS TONIGHT SIMILAR TO SATURDAY NIGHT, AND HIGHS MONDAY A TAD WARMER THAN SUNDAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... SHORT WAVE WILL CREST THE UPPER RIDGE AND WEAKEN THROUGH THE PERIOD SEVERELY LIMITING ANY ADDITIONAL SHOWER ACTIVITY. WITH SOME LOW LEVEL MOISTURE PRESENT...KEPT SLIGHT CHANCE POPS THROUGH TUESDAY MORNING BEFORE BACKING OFF TO ONLY THE RIDGES. BOTH MAV/MET GUIDANCE HAVE TEMPERATURES REACHING VERY CLOSE TO 80 BY MIDWEEK AND WITH STRONG RIDGE STATIONED TO THE EAST AND SOUTHERLY FLOW...FELT NO REASON TO STRAY FROM THESE NUMBERS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... REGION WILL BE UNDER AN UPPER LEVEL RIDGE INTO THURSDAY WITH MILD TEMPERATURES. THERE MAY BE ENOUGH LOW LEVEL MOISTURE THAT A DIURNAL SHOWER IS POSSIBLE THURSDAY...BUT OVERALL A DRY FORECAST. LARGE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL GRADUALLY COME EAST BY FRIDAY WITH SHOWERS INTO SATURDAY. MODELS HAVE TIMING DIFFERENCES BY THE DAY 7 TIME PERIOD WITH A SHOT OF COLDER AIR MOVING DOWN FROM THE NORTHERN PLAINS BEHIND THE SATURDAY SYSTEM. USED HPC GUIDANCE FOR CONSISTENCY. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... MAIN FORECAST CONCERN WILL BE IN THE FIRST 6 HOURS OF TAF PERIOD. AN AREA OF SHOWERS AND STORMS HAS DEVELOPED OVER OHIO AND IS SWINGING TO THE EAST. LATEST HIRES MODEL DATA SHOWS THIS AREA CONTINUING TO MOVE EASTWARD, BUT WEAKENING. FOR CURRENT FORECAST, WILL PUT IN TEMPO GROUPS FOR RESTRICTIONS AT ALL PORTS FOR THE EVENING HOURS. WILL ONLY MENTION THUNDER, WITH GUSTY WINDS AT ZZV, AS CURRENT RADAR AND SAT TRENDS ARE SHOWING THE ACTIVITY WEAKENING. BEHIND THE RAIN, EXPECT GENERAL VFR CONDITIONS TO RETURN, HOWEVER THERE WILL BE IFR/MVFR FOG DEVELOPING. AFTER FOG DISSIPATES MONDAY MORNING, VFR CONDITIONS FOR THE REMAINDER OF THE DAY. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... HIGH PRESSURE WILL DOMINATE INTO THURSDAY WITH GENERAL VFR CONDITIONS. SHOWERS AND POSSIBLE RESTRICTIONS WILL RETURN FRIDAY AS A STORM SYSTEM MOVES EAST FROM THE CENTRAL PLAINS STATES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EDT SAT MAR 17 2012 .SYNOPSIS... ISSUED AT 428 PM EDT SAT MAR 17 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH NEAR THE WEST COAST AND A BROAD DOWNSTREAM RIDGE OVER THE CNTRL AND ERN CONUS RESULTING IN SW FLOW INTO THE UPPER GREAT LAKES. AT THE SFC...SRLY FLOW AHEAD OF A TROUGH OVER THE PLAINS HAS BROUGHT GULF MOISTURE AND RECORD BREAKING WARM AIR FROM THE PLAINS AND MS VALLEY INTO THE WRN GREAT LAKES AND NRN ONTARIO. DESPITE CAPE VALUES INTO TO AROUND 2K J/KG...ENOUGH CAPPING PREVAILED OVER THE CWA...PER 12Z KMPX SOUNDING TO PREVENT TSRA DEVELOPMENT OVER THE CWA. HOWEVER...CONVECTION HAD DEVELOPED ABOVE THE MARINE LAYER NEAR THE STRAITS...WHERE THE CAP WAS WEAKER. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 428 PM EDT SAT MAR 17 2012 TONIGHT INTO SUNDAY...UNSEASONABLY WARM AND MOIST CONDITIONS WILL CONTINUE ACROSS THE AREA AS LOW LEVEL MOISTURE REMAINS IN PLACE ALONG WITH RELATIVELY STEEP MID LEVEL LAPSE RATES FROM 7.5C-8.5C/KM. THIS INSTABILITY WOULD BE ENOUGH TO WARRANT KEEPING SLIGHT CHC POPS FOR TSRA POTENTIAL OVER THE AREA. HOWEVER...ANY SHORTWAVES LIFTING INTO THE NRN GREAT LAKES ARE EXPECTED TO BE WEAK AND THE GREATEST ISENTROPIC LIFT NEAR THE NOSE OF THE LOW LEVEL JET 850 MB WARM FRONT AND WEAKER CAPPING SHOULD REMAIN NORTH AND EAST OF THE CWA...PER MODEL DATA. WITH HIGHER DEWPOINTS...EXPECT MORE FOG/STRATUS DEVELOPMENT...ESPECIALLY OFF OF LAKE MICHIGAN AND AREAS WITH UPSLOPE SRLY FLOW. RECORD HIGH MINIMUM VALUES ARE EXPECTED WITH LOWS ONLY DROPPING INTO THE LOWER 50S AT MOST LOCATIONS. STRONG SRLY FLOW AND WAA WILL PUSH 850 MB TEMPS INTO THE 12C TO 14C RANGE. SO...WITH SUNSHINE AND DECENT MIXING...EXPECT HIGH TEMPS AGAIN WELL INTO 70S ACROSS THE W HALF OF UPPER MI AND PERHAPS EVEN LOWER 80S AT SOME SPOTS. TEMPS WILL REMAIN SUBSTANTIALLY LOWER DOWNWIND OF LAKE MICHIGAN WHERE READINGS WILL BE IN THE LOWER 50S ALONG THE SHORE TO LOWER 60S WELL INLAND. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 428 PM EDT SAT MAR 17 2012 WHAT GOES UP /OUR STRETCH OF UNSEASONABLE WARM TEMPERATURES/ MUST GO DOWN...EVENTUALLY...BUT THE MAIN QUESTION IS THE DEGREE IT WILL GO DOWN. DEEP TROUGH OVER FAR WESTERN CONUS IS FCST TO COME EAST THROUGHOUT THE WEEK. GOOD AGREEMENT IN OVERALL SCENARIO THROUGH ROUGHLY MID WEEK...THEN MODEL DIFFERENCES START CREEPING INTO THE PICTURE BY LATE WEEK/NEXT WEEKEND. MAIN ISSUE AT THAT TIME IS HOW MUCH TROUGHING/COLD AIR WILL BE OVER THE UPR LAKES FRIDAY INTO SATURDAY. MODELS EARLIER THIS WEEK SHOWED MAIN TROUGH SPLITTING INTO TWO...WITH MORE OF A CUTOFF LOW OVER SOUTHERN PLAINS MEANDERING ACROSS CNTRL CONUS...BUT MAINLY REMAINING SOUTH OF UPR LAKES. MORE RECENT MODEL RUNS SHOWED MORE PHASING BTWN THE TWO TROUGHS OVR THE UPR LAKES BY LATE WEEK. LATELY THE MODELS AND ENSEMBLES ARE INDICATING MORE SPLIT PATTERN AGAIN. ECMWF IS THE ONLY MODEL SHOWING MORE OF A PHASED LOOK WHILE ECMWF ENSEMBLES DEVELOP TROUGH FARTHER EAST...ALLOWING HEIGHTS TO REBOUND OVR UPR LAKES AS QUICKLY AS NEXT SATURDAY. INITIALLY TO START THE LONGER RANGE WARM AND MOIST SOUTHERLY FLOW REGIME WILL BE IN FULL SWING SOUTH OF WARM FRONT. NOT A WHOLE LOT OF LARGER SCALE FEATURES TO PIN POPS TO SUNDAY NIGHT AND MONDAY. LOOKS LIKE THERE ARE A FEW AREAS OF ISENTROPIC ASCENT FLOWING INTO THE UPR LAKES THAT MAY TRIGGER CONVECTION IN THE MOIST ENVIRONMENT. BETTER CHANCE WOULD BE OVER WEST AND NORTHWEST CWA. NOTHING MORE THAN SLIGHT CHANCES THOUGH GIVEN LACK OF SUPPORT FM SHORTWAVES AND UPR JET SUPPORT. THUNDER CHANCES SEEM PRETTY REMOTE AS H7-H5 LAPSE RATES ARE DECREASING WITH ARRIVAL OF WARM AIR ALOFT. SI/S START OUT SUNDAY NIGHT INTO MONDAY A BIT BLO 0C BUT BY LATER MONDAY INTO MONDAY NIGHT STABILITY ONLY INCREASES. WELL ABOVE NORMAL TEMPERATURES SHOULD CONTINUE THROUGH MIDWEEK WITH MORE RECORD HIGHS EXPECTED. COOLING TREND IS EXPECTED BY LATE WEEK INTO NEXT WEEKEND AS PLAINS TROUGH SLIDES INTO CNTRL CONUS. GREATEST CHANCE OF RAIN FOR THE WEEK OCCURS WEDNESDAY AS FRONTAL BOUNDARY AHEAD OF TROUGH/POOLING MOISTURE ALONG THE FRONT AND RIGHT ENTRANCE FORCING FM UPR JET CONGEAL OVR UPR LAKES. DESPITE ABUNDANCE OF MOISTURE STREAMING NORTH /PWATS OVR 300 PCT OF NORMAL/ NOT SURE THAT WILL EQUATE TO WIDESPREAD SOAKING RAIN OVR THE CWA. WHERE IT DOES RAIN...IT COULD BE HEAVY AT TIMES THOUGH. FOR NOW HAVE HIGHEST POPS ON WEDNESDAY OVER THE NORTHERN CWA CLOSER TO INFLUENCE OF UPR JET OVR ONTARIO. EVENTUALLY THOUGH POPS MAY NEED TO BE PUSHED INTO THE LIKELY CATEGORY OVR MUCH OF CWA. EXTENT OF TROUGHING/COOLING STILL IN QUESTION FOR LATE WEEK AND NEXT WEEKEND. ECMWF CONTINUES ITS TREND OF SHARPER TROUGHING AND COOLER TEMPS /H85 TEMPS BLO -5C/ WHICH WOULD RESULT IN MORE CLOUDS THAN CURRENT FCST SHOWS AND TEMPS COOLING INTO THE 30S. CHANCES OF PCPN APPEAR LOW THOUGH AS ALTHOUGH IT WOULD BE COOL IT LOOKS FAIRLY DRY AS WELL. GIVEN LACK OF CONSISTENCY IN MODEL SOLUTIONS HAVE NOT STRAYED TOO FAR FM CONSENSUS AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 133 PM EDT SAT MAR 17 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT ALL SITES EXCEPT TONIGHT INTO SUN MORNING AT SAW. LLWS WILL ALSO BE PRESENT AT ALL SITES EARLY THIS MORNING AND THEN AGAIN TONIGHT. CONFIDENCE IS FAIRLY HIGH THAT ABUNDANT OF LOW-LEVEL MOISTURE WILL LEAD TO MORE STRATUS AND FOG AT KSAW TONIGHT WITH UPSLOPE SSE FLOW. AIRFIELD LANDING MINIMUMS COULD BE APPROACHED AT KSAW BY LATE EVENING OR OVERNIGHT. THERE IS ALSO A SLIM RISK OF ISOLD SHRA/TSRA AT ALL THREE SITES INTO TONIGHT. HOWEVER...CHANCE IS JUST TOO LOW AT THIS POINT TO EVEN MENTION A CB IN THE CLOUD GROUP. FOG/STRATUS AT KSAW SHOULD LIFT BY AROUND 15Z SUNDAY MORNING WITH DIURNAL MIXING...SIMILAR TO TODAY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 428 PM EDT SAT MAR 17 2012 EXPECT GENERALLY S-SE WINDS LESS THAN 25 KTS INTO NEXT WEEK AS HIGH PRESSURE DOMINATES OVER THE UPR GREAT LAKES REGION. UNSEASONABLY WARM AIR OVER THE UPPER GREAT LAKES WILL ALSO RESULT IN PERSISTENT MARINE LAYER/STRONG STABILITY OVER THE LAKE. WITH THE UNSEASONABLY HIGH DEWPOINTS MOVING INTO THE AREA...AREAS OF FOG WILL ALSO CONTINUE OVER THE AREA WITH LCLY DENSE FOG POSSIBLE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
335 PM CDT SAT MAR 17 2012 .DISCUSSION... LARGE CU AND LEFT OVER STRATUS FILED STILL WITH US LATE THIS AFTERNOON BUT THINNING OUT IN THE WEST..ESPECIALLY LEE OF THE BUFFALO RIDGE INTO THE UPPER MN RIVER VALLEY. WE ARE GENERALLY IN A BROAD WARM SECTOR WITH PLENTY OF ML CAPE BUT THE GREATER 0-3KM CAPE IS WELL OFF TO THE EAST ON WI. ANY DEFINED SURFACE BOUNDARIES ARE IN FAR NORTHERN MINNESOTA AND IN THE CENTRAL DAKOTAS NEAR THE PSEUDO DRY LINE. LATEST AIRCRAFT SOUNDING OUT OF KMSP STILL SHOWING A DECENT INVERSION. LOOKS LIKE A SIMILAR SITUATION TONIGHT FOR REDEVELOPMENT OF THE LOW CLOUDS OVERNIGHT. LATEST RUC PROFILES AND THE 12Z NAM SHOWING THIS TREND AND SEEMS REASONABLE BASED ON CU FIELD ITO THE SOUTHERN PLAINS. WE MAY SEE A PERIOD OF SKC HERE AND THERE BEFORE REDEVELOPMENT LATE TONIGHT OR EARLY SUNDAY MORNING. NO TRIGGERS OR SIGNIFICANT ADVECTIVE FIELDS UNTIL SUNDAY NIGHT WHEN BOTH THE EC AND NAM SHOW A WEAK WAVE MOVING NORTHEAST THROUGH THE PLAINS. LOTS OF ML CIN OVER THE AREA ON SUNDAY AS WELL. IT LOOKS WEAK AT THIS POINT SO WILL CONTINUE THE SLIGHT CHANCE OVER SOUTH CENTRAL AND SOUTHWEST MINNESOTA LATER SUNDAY NIGHT. THE MAIN PUSH OF FORCING AND HIGH PRECIPITABLE WATER OUT OF THE LONG WEAVE TROUGH WILL BE MONDAY INTO TUESDAY. BOTH THE NAM AND GFS ARE FORECASTING PWAT VALUES CLOSE TO 1.2 INCHES WHICH WOULD BE AT "RECORD LEVELS" BASED ON THE CLIMATOLOGY STUDY OF CONUS RAOB SITES. QUITE A MERIDIONAL UPPER FLOW AS THIS WAVE MOVES OUT...WITH DECREASED SHEAR. SEVERE CHANCES STILL IN QUESTION BUT CANT RULE OUT A FEW STRONG STORMS BEFORE THE MORE SATURATED CONDITIONS DEVELOP. WILL UP POPS IN A FEW AREAS..ESPECIALLY WEST INITIALLY WITH HIGHER POPS CONTINUING EAST INTO TUESDAY. CUTTING OFF OF AN UPPER LOW OVER THE SOUTHERN PLAINS LOOKS REASONABLE MID WEEK WHICH COULD CUT OF THE LINGERING LOWER POPS THAT WE HAVE LATER IN THE WEEK. THE EC LOOKS TO BE MORE CUT OFF THAN THE GFS. && .AVIATION.../18Z TAF ISSUANCE/ ALL IT TOOK WITH ALL THE JUICE IN THE AIR THIS MORNING TO GET IFR/MVFR STRATUS GOING WAS A LITTLE BIT OF LIFT ASSOCIATED WITH GETTING MIXING GOING. SATELLITE SHOWS CLOUDS BEGINNING TO BECOME CELLULAR IN NATURE WHILE OBS LIFTING AT THE SAME TIME. IFR CONDITIONS ARE DONE...AND MVFR CIGS SHOULD ONLY LAST AN HOUR OR TWO BEFORE SKIES SLOWLY WORK BACK TOWARD SKC AROUND SUNSET. LITTLE CHANGE IN THE ATMOSPHERE IS EXPECTED OVERNIGHT...SO RELIED HEAVILY ON PERSISTENCE WHEN IT CAME TO IFR/MVFR CIGS IN TAFS SUNDAY MORNING. LIKE TODAY...WILL BE PLENTY OF MOISTURE IN THE LOWER LEVELS FOR FG/STRATUS...BUT WINDS WILL KEEP THINGS MIXED...WITH VIS ONLY DROPPING OFF INTO THE MVFR...POSSIBLE IFR RANGE. CLOUDS NOT EXPECTED TO FORM UNTIL A SOURCE OF LIFT SHOWS UP...WHICH WOULD BE SOLAR HEATING. ONCE AGAIN...ANTICIPATE CLOUDS TO FORM WITHIN AN HOUR OR TWO AFTER SUNRISE...WITH SKIES REMAINING MOSTLY CLOUDY THROUGH THE MORNING. ONE WORRY FOR THIS SCENARIO IS THAT LOW PRESSURE THAT WAS OVER THE CENTRAL/ERN DAKOTAS THIS MORNING WILL BE OVER ERN MT SUNDAY MORNING. AREAS OF WI FURTHER FROM THE DAKOTAS LOW THIS MORNING SAW NO LOW CLOUDS DEVELOP. IN ADDITION...TRAJECTORY PLOTS SHOW LOW LEVEL AIR SUNDAY MORNING ORIGINATING FROM SRN MO THIS MORNING...WHERE THERE WAS NOT STRATUS. BASED ON THIS...WOULD NOT BE SURPRISED IF WE WOUND UP STRATUS FREE...THOUGH NAM/GFS BUFKIT SOUNDINGS WOULD CERTAINLY LEAN TOWARD THE STRATUS SCENARIO. WIND DIRECTION NOT EXPECTED TO CHANGE MUCH AT ALL...WITH SPEEDS FOLLOWING A TYPICAL DIURNAL TREND...WITH SPEEDS TONIGHT SIMILAR TO LAST NIGHT AND SPEEDS SUNDAY SIMILAR TO/SLIGHTLY STRONGER THAN TODAY. KMSP...EXPECT MVFR CIGS TO LIFT INTO A VFR BKN CIG WITHIN THE HOUR. AS BREAKS IN OVC GROW...INCREASED MIXING WILL FURTHER LIFT THE CIGS TO AROUND 4K FT...WITH SKY COVER SLOWLY DIMINISHING THROUGH THE AFTERNOON. PLAYED A SIMILAR TREND IN CIGS SUNDAY MORNING TO WHAT WAS SEEN THIS MORNING. NOT COMPLETELY CONFIDENT IN THIS PLAYING OUT...AS THE SHIFT IN THE SFC LOW BACK TO THE WEST MAY END UP SHIFTING STRATUS FORMATION THAT WAS SEEN OVER MN TODAY INTO THE DAKOTAS TOMORROW. //OUTLOOK...MON THROUGH THURSDAY... .MON-TUE...IFR/MVFR CIGS POSSIBLE. SHRA/TSRA LIKELY WITH SLOW FROPA. .WED-THU...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
118 PM CDT SAT MAR 17 2012 .UPDATE... 18Z AVIATION DISCUSSION ADDED. && .PREV DISCUSSION... /ISSUED 732 AM CDT SAT MAR 17 2012/ LATEST WV IMAGERY OVERLAID WITH RUC 400-500MB LAYER WINDS SHOWS SUBTLE SHORTWAVE RESPONSIBLE FOR THE EVENING CONVECTION ACROSS NORTHERN WISCONSIN HAS MOVED NORTHEAST. MEANWHILE...ANOTHER WEAK WAVE IS FORCING A FEW SHOWERS ACROSS SOUTHWEST WISCONSIN...BUT THIS WILL REMAIN SOUTH AND EAST OF THE FORECAST AREA. FURTHER UPSTREAM ANOTHER SHORT WAVE LOCATED OVER KANSAS WILL MOVE NORTHEAST TODAY...BUT IT TOO SHOULD TRACK SOUTH AND EAST OF THE CWA. GIVEN THE SUMMER LIKE AIRMASS IN PLACE...AS INDICATED BY THE TROPOPAUSE HEIGHT OF 225 MB VIA THE 00Z MPX RAOB...A SMALL AMOUNT FORCING IS SUFFICIENT TO PRODUCE CONVECTION. HOWEVER...HAVE KEPT THE FORECAST DRY FOR TODAY AND SUNDAY SINCE CONFIDENCE IS LOW THAT SHOWERS AND THUNDERSTORMS WILL DEVELOP DESPITE THE HIGH CAPE VALUES. THINKING IS THAT A WIDESPREAD CUMULUS FIELD WILL ENSUE RATHER THAN ANY DEEP CONVECTION. BY SUNDAY NIGHT A LONG WAVE TROUGH THAT IS CURRENTLY DIGGING OFF THE COAST OF CALIFORNIA WILL BEGIN TO AFFECT THE UPPER MIDWEST. MODELS SHOW A WEAK SHORTWAVE MOVING UP FROM THE SOUTHWEST IN CONJUNCTION WITH A STRENGTHENING LOW LEVEL JET. THIS SHOULD TRIGGER SOME SHOWER AND THUNDERSTORM DEVELOPMENT SUNDAY NIGHT INTO MONDAY. THE BEST DYNAMICS REMAIN TO THE WEST IN THE VICINITY OF A +120KT GET...SO DEEP LAYER SHEAR VALUES IN THE 20-25KT RANGE INDICATE A MINIMAL THREAT FOR SEVERE WEATHER. THIS IS ALSO SUPPORTED BY THE NARROW CAPE PROFILES IN THE FORECAST SOUNDINGS. LOOKS LIKE SOME MUCH NEEDED RAIN SHOWERS WILL BE THE MAIN RESULT...WITH A FEW SUB SEVERE THUNDERSTORMS MIXED IN AS WELL. MODELS THEN TRANSITION THIS TROUGH TO A CUTOFF LOW ON WEDNESDAY AND VARY IN LOCATION. THE GEM 17.00 IS FURTHEST SOUTH OVER ARKANSAS...WHILE THE ECMWF TAKES IT ACROSS THE OHIO RIVER VALLEY...AND THE GFS 17.00 IS SLOW TO MOVE THIS SYSTEM OUT FROM THE CENTRAL CONUS. GIVEN THE MODEL UNCERTAINTY...DID NOT DEVIATE MUCH FROM GUIDANCE IN THE EXTENDED. && .AVIATION.../18Z TAF ISSUANCE/ ALL IT TOOK WITH ALL THE JUICE IN THE AIR THIS MORNING TO GET IFR/MVFR STRATUS GOING WAS A LITTLE BIT OF LIFT ASSOCIATED WITH GETTING MIXING GOING. SATELLITE SHOWS CLOUDS BEGINNING TO BECOME CELLULAR IN NATURE WHILE OBS LIFTING AT THE SAME TIME. IFR CONDITIONS ARE DONE...AND MVFR CIGS SHOULD ONLY LAST AN HOUR OR TWO BEFORE SKIES SLOWLY WORK BACK TOWARD SKC AROUND SUNSET. LITTLE CHANGE IN THE ATMOSPHERE IS EXPECTED OVERNIGHT...SO RELIED HEAVILY ON PERSISTENCE WHEN IT CAME TO IFR/MVFR CIGS IN TAFS SUNDAY MORNING. LIKE TODAY...WILL BE PLENTY OF MOISTURE IN THE LOWER LEVELS FOR FG/STRATUS...BUT WINDS WILL KEEP THINGS MIXED...WITH VIS ONLY DROPPING OFF INTO THE MVFR...POSSIBLE IFR RANGE. CLOUDS NOT EXPECTED TO FORM UNTIL A SOURCE OF LIFT SHOWS UP...WHICH WOULD BE SOLAR HEATING. ONCE AGAIN...ANTICIPATE CLOUDS TO FORM WITHIN AN HOUR OR TWO AFTER SUNRISE...WITH SKIES REMAINING MOSTLY CLOUDY THROUGH THE MORNING. ONE WORRY FOR THIS SCENARIO IS THAT LOW PRESSURE THAT WAS OVER THE CENTRAL/ERN DAKOTAS THIS MORNING WILL BE OVER ERN MT SUNDAY MORNING. AREAS OF WI FURTHER FROM THE DAKOTAS LOW THIS MORNING SAW NO LOW CLOUDS DEVELOP. IN ADDITION...TRAJECTORY PLOTS SHOW LOW LEVEL AIR SUNDAY MORNING ORIGINATING FROM SRN MO THIS MORNING...WHERE THERE WAS NOT STRATUS. BASED ON THIS...WOULD NOT BE SURPRISED IF WE WOUND UP STRATUS FREE...THOUGH NAM/GFS BUFKIT SOUNDINGS WOULD CERTAINLY LEAN TOWARD THE STRATUS SCENARIO. WIND DIRECTION NOT EXPECTED TO CHANGE MUCH AT ALL...WITH SPEEDS FOLLOWING A TYPICAL DIURNAL TREND...WITH SPEEDS TONIGHT SIMILAR TO LAST NIGHT AND SPEEDS SUNDAY SIMILAR TO/SLIGHTLY STRONGER THAN TODAY. KMSP...EXPECT MVFR CIGS TO LIFT INTO A VFR BKN CIG WITHIN THE HOUR. AS BREAKS IN OVC GROW...INCREASED MIXING WILL FURTHER LIFT THE CIGS TO AROUND 4K FT...WITH SKY COVER SLOWLY DIMINISHING THROUGH THE AFTERNOON. PLAYED A SIMILAR TREND IN CIGS SUNDAY MORNING TO WHAT WAS SEEN THIS MORNING. NOT COMPLETELY CONFIDENT IN THIS PLAYING OUT...AS THE SHIFT IN THE SFC LOW BACK TO THE WEST MAY END UP SHIFTING STRATUS FORMATION THAT WAS SEEN OVER MN TODAY INTO THE DAKOTAS TOMORROW. //OUTLOOK...MON THROUGH THURSDAY... .MON-TUE...IFR/MVFR CIGS POSSIBLE. SHRA/TSRA LIKELY WITH SLOW FROPA. .WED-THU...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JRB/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
732 AM CDT SAT MAR 17 2012 .UPDATE... UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW. .DISCUSSION... LATEST WV IMAGERY OVERLAID WITH RUC 400-500MB LAYER WINDS SHOWS SUBTLE SHORTWAVE RESPONSIBLE FOR THE EVENING CONVECTION ACROSS NORTHERN WISCONSIN HAS MOVED NORTHEAST. MEANWHILE...ANOTHER WEAK WAVE IS FORCING A FEW SHOWERS ACROSS SOUTHWEST WISCONSIN...BUT THIS WILL REMAIN SOUTH AND EAST OF THE FORECAST AREA. FURTHER UPSTREAM ANOTHER SHORT WAVE LOCATED OVER KANSAS WILL MOVE NORTHEAST TODAY...BUT IT TOO SHOULD TRACK SOUTH AND EAST OF THE CWA. GIVEN THE SUMMER LIKE AIRMASS IN PLACE...AS INDICATED BY THE TROPOPAUSE HEIGHT OF 225 MB VIA THE 00Z MPS RAOB...A SMALL AMOUNT FORCING IS SUFFICIENT TO PRODUCE CONVECTION. HOWEVER...HAVE KEPT THE FORECAST DRY FOR TODAY AND SUNDAY SINCE CONFIDENCE IS LOW THAT SHOWERS AND THUNDERSTORMS WILL DEVELOP DESPITE THE HIGH CAPE VALUES. THINKING IS THAT A WIDESPREAD CUMULUS FIELD WILL ENSUE RATHER THAN ANY DEEP CONVECTION. BY SUNDAY NIGHT A LONG WAVE TROUGH THAT IS CURRENTLY DIGGING OFF THE COAST OF CALIFORNIA WILL BEGIN TO AFFECT THE UPPER MIDWEST. MODELS SHOW A WEAK SHORTWAVE MOVING UP FROM THE SOUTHWEST IN CONJUNCTION WITH A STRENGTHENING LOW LEVEL JET. THIS SHOULD TRIGGER SOME SHOWER AND THUNDERSTORM DEVELOPMENT SUNDAY NIGHT INTO MONDAY. THE BEST DYNAMICS REMAIN TO THE WEST IN THE VICINITY OF A +120KT GET...SO DEEP LAYER SHEAR VALUES IN THE 20-25KT RANGE INDICATE A MINIMAL THREAT FOR SEVERE WEATHER. THIS IS ALSO SUPPORTED BY THE NARROW CAPE PROFILES IN THE FORECAST SOUNDINGS. LOOKS LIKE SOME MUCH NEEDED RAIN SHOWERS WILL BE THE MAIN RESULT...WITH A FEW SUB SEVERE THUNDERSTORMS MIXED IN AS WELL. MODELS THEN TRANSITION THIS TROUGH TO A CUTOFF LOW ON WEDNESDAY AND VARY IN LOCATION. THE GEM 17.00 IS FURTHEST SOUTH OVER ARKANSAS...WHILE THE ECMWF TAKES IT ACROSS THE OHIO RIVER VALLEY...AND THE GFS 17.00 IS SLOW TO MOVE THIS SYSTEM OUT FROM THE CENTRAL CONUS. GIVEN THE MODEL UNCERTAINTY...DID NOT DEVIATE MUCH FROM GUIDANCE IN THE EXTENDED. && .AVIATION.../12Z TAF ISSUANCE/ THIS MORNING IS QUITE SIMILAR TO WHAT WAS OBSERVED FRIDAY MORNING - VFR STRATUS IN EASTERN MN AND WESTERN WI...MVFR/IFR CEILINGS DEVELOPING IN NORTHWEST IA AND NORTHEAST NE AND ADVECTING NORTH WITH TIME. ONCE AGAIN KRWF IS IN THE BEST SPOT TO SEE 1500FT CEILINGS MOVE IN FOR A COUPLE HOURS LATE THIS MORNING. CIGS/VIS WON`T BE NEARLY AS POOR TODAY HOWEVER. PLENTY OF 4-5SM FOG ACROSS THE REST OF THE AREA THAT WILL QUICKLY BURN OFF ONCE THE SUN GETS UP ABOVE THE HORIZON. THE WIND IS HELPING TO KEEP THE FOG IN CHECK. TOWERING CUMULUS WITH BASES BETWEEN 3500-6000FT APPEAR LIKELY ONCE AGAIN BY THIS AFTERNOON. THERE ARE A COUPLE MORE RIPPLES IN THE ATMOSPHERE THAT MIGHT KICK OFF ANOTHER ROUND OF SHOWERS AND STORMS IN WI/IA/IL LATE THIS AFTERNOON...BUT WHAT ACTIVITY FORMS SHOULD BE SOUTH OF THE TAF SITES. THE WAVE THAT COULD TRIGGER STORMS IS BACK IN KS/NE AND SHOULD TAKE 9-12HRS TO MAKE IT TO WI. SAME STORY SUNDAY MORING - HOW MUCH FOG/STRATUS WILL THERE BE? THERE IS NO CHANGE IN AIR MASS...HAVE A LOT OF MVFR NEAR THE END OF THE TAF. KMSP...SKIES SHOULD ONCE AGAIN FILL WITH CUMULUS CLOUDS WITH DECENT VERTICAL EXTENT THIS AFTERNOON AFTER A MOSTLY CLEAR MORNING. VFR CONDITIONS EXPECTED THROUGHOUT THE DAY. SOME INDICATION OF ANOTHER STRATUS DECK AND FOG EARLY SUNDAY MORNING. HOWEVER...WE HAVE OVERDONE THE MVFR/IFR CONDITIONS THE LAST COUPLE MORNINGS EVEN THOUGH THERE HAS BEEN PLENTY OF LOW LEVEL MOISTURE. SHOULD SEE WINDS REALLY PICK UP EARLY THIS AFTERNOON AND THERE WONT BE MUCH CHANGE IN DIRECTION FROM WHERE WE ARE NOW. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JRB/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
403 AM CDT SAT MAR 17 2012 .DISCUSSION... LATEST WV IMAGERY OVERLAID WITH RUC 400-500MB LAYER WINDS SHOWS SUBTLE SHORTWAVE RESPONSIBLE FOR THE EVENING CONVECTION ACROSS NORTHERN WISCONSIN HAS MOVED NORTHEAST. MEANWHILE...ANOTHER WEAK WAVE IS FORCING A FEW SHOWERS ACROSS SOUTHWEST WISCONSIN...BUT THIS WILL REMAIN SOUTH AND EAST OF THE FORECAST AREA. FURTHER UPSTREAM ANOTHER SHORT WAVE LOCATED OVER KANSAS WILL MOVE NORTHEAST TODAY...BUT IT TOO SHOULD TRACK SOUTH AND EAST OF THE CWA. GIVEN THE SUMMER LIKE AIRMASS IN PLACE...AS INDICATED BY THE TROPOPAUSE HEIGHT OF 225 MB VIA THE 00Z MPS RAOB...A SMALL AMOUNT FORCING IS SUFFICIENT TO PRODUCE CONVECTION. HOWEVER...HAVE KEPT THE FORECAST DRY FOR TODAY AND SUNDAY SINCE CONFIDENCE IS LOW THAT SHOWERS AND THUNDERSTORMS WILL DEVELOP DESPITE THE HIGH CAPE VALUES. THINKING IS THAT A WIDESPREAD CUMULUS FIELD WILL ENSUE RATHER THAN ANY DEEP CONVECTION. BY SUNDAY NIGHT A LONG WAVE TROUGH THAT IS CURRENTLY DIGGING OFF THE COAST OF CALIFORNIA WILL BEGIN TO AFFECT THE UPPER MIDWEST. MODELS SHOW A WEAK SHORTWAVE MOVING UP FROM THE SOUTHWEST IN CONJUNCTION WITH A STRENGTHENING LOW LEVEL JET. THIS SHOULD TRIGGER SOME SHOWER AND THUNDERSTORM DEVELOPMENT SUNDAY NIGHT INTO MONDAY. THE BEST DYNAMICS REMAIN TO THE WEST IN THE VICINITY OF A +120KT GET...SO DEEP LAYER SHEAR VALUES IN THE 20-25KT RANGE INDICATE A MINIMAL THREAT FOR SEVERE WEATHER. THIS IS ALSO SUPPORTED BY THE NARROW CAPE PROFILES IN THE FORECAST SOUNDINGS. LOOKS LIKE SOME MUCH NEEDED RAIN SHOWERS WILL BE THE MAIN RESULT...WITH A FEW SUB SEVERE THUNDERSTORMS MIXED IN AS WELL. MODELS THEN TRANSITION THIS TROUGH TO A CUTOFF LOW ON WEDNESDAY AND VARY IN LOCATION. THE GEM 17.00 IS FURTHEST SOUTH OVER ARKANSAS...WHILE THE ECMWF TAKES IT ACROSS THE OHIO RIVER VALLEY...AND THE GFS 17.00 IS SLOW TO MOVE THIS SYSTEM OUT FROM THE CENTRAL CONUS. GIVEN THE MODEL UNCERTAINTY...DID NOT DEVIATE MUCH FROM GUIDANCE IN THE EXTENDED. && .AVIATION.../06Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED EARLY ON WITH FEW-SCT060-080 MOVING THROUGH MAINLY EASTERN AREAS. WEAK WAVE LIFTING NORTHEAST OVER EASTERN NE THIS EVENING...IS GENERATING A FEW OF THESE CLOUDS SOUTH OVER IOWA AND MAY LIFT INTO THE AREA THIS MORNING. STILL A QUANDARY WHETHER OR NOT STRATUS WILL DEVELOP DURING THE MORNING. STILL HAVE DECENT PRESSURE GRADIENT/WINDS AROUND...AND WILL LIMIT VSBY REDUCTION SOMEWHAT. DEWPOINTS REMAIN HIGH HOWEVER...AND BUFKIT PROFILES STILL SUGGEST POSSIBLITY OF STRATUS DEVELOPMENT LATE. WILL HOLD ONTO SOME OF THAT LIFR/IFR OVER WESTERN AREAS AND NOT SO MUCH TO THE EAST. ONLY POSSIBLE PROBLEM WOULD BE KEAU WHICH SAW A TSRA THIS EVENING. DO ANTICIPATE IFR LIFTING TO MVFR AND THEN VFR MOST AREAS THROUGN 19Z. MODELS SUGGEST QUITE A BIT OF LOW LEVEL RH AROUND SO WILL KEEP A BKN VFR CEILING INTO THE AFTERNOON/EVENING. SOUTHEAST TO SOUTH WINDS TO INCREASE AS GRADIENT INCREASES AHEAD OF WESTERN TROUGH...GUSTS OVER 25KTS POSSIBLE...ESPECIALLY OVER WSTERN AREAS IN THE AFTERNOON. KMSP...FEW 060-080 CLOUDS AROUND THE AREA...AND SOME MAY YET WORK NORTH THROUGH IOWA OVERNIGHT. THIS ALONG WITH CONTINUATION OF SOME GRADIENT WIND SHOULD LIMIT SIGNIFICANT FOG FORMATION. STILL A QUESTION AS TO WHETHER STRATUS DEVELOPMENT WILL TAKE PLACE. KEPT SOME LOWER FEW005 IN THERE LATER TONIGHT BUT FEEL BEST THREAT OF IFR CONDITIONS OCCURRING WILL BE FARTHER WEST. STILL ANTICIAPTE CLOUDS TO START THE DAY...MIXING OUT IN THE AFTERNOON. SOUTHEAST TO SOUTH WINDS EXPECTED TO INCREASE AS WELL AND BECOME GUSTY IN THE AFTERNOON. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ 99/99
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
920 AM CDT SAT MAR 17 2012 .UPDATED...LATEST SATELLITE IMAGERY SHOWED THAT THE REGION WAS UNDER THE INFLUENCE OF A STRONG MEAN RIDGE. THIS WAS NOTED BY THIS MORNINGS UPPER SOUNDING...WHICH REQUIRED AROUND 98 DEGREES SURFACE TEMP TO BREAK THE MEGA MID LEVEL CAP AT 700 MB. THERE WERE SOME MINOR PERTURBATIONS IN THE UPPER WEST SOUTHWEST FLOW COMING FROM THE SOUTHERN PLAINS. LATEST HIGH RESOLUTION MODELS AND RUC SHOW THAT THE CAP WILL HOLD AND WE MAY SEE SOME ISOLATED CONVECTION IN THE NORTH AS A WEAK SHORT WAVES PASSES NORTH OF THE REGION. SO KEPT LOW ISOLATED POPS THERE. CURRENT HIGHS 82-84 LOOKS TO BE ON TRACK. LOW LEVEL WINDS IN THE MORNING SOUND WERE ON THE LIGHT SIDE. HAVE ALLOWED THE DENSE FOG ADVISORY IN THE SOUTH TO EXPIRE. PIB WAS HOLDING ON AT 1/2 MILE...BUT EXPECT THAT TO LIFT BY AROUND 15Z. OTHERWISE THE REST OF THE FORECAST APPEARS TO BE ON TRACK./17/ ./PREVIOUS DISCUSSION...443 AM CDT SAT MAR 17 2012 .DISCUSSION... A WARM AND MOSTLY DRY PATTERN WILL CONTINUE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...THEN A LARGE UPPER TROUGH WILL APPROACH THE ARKLAMISS FOR THE MIDDLE OF NEXT WEEK BRINGING THE CHANCE FOR HEAVY RAINFALL AND A FEW STRONG TO SEVERE STORMS. TODAY THROUGH SUNDAY NIGHT... A STRONG MID LEVEL RIDGE AXIS CURRENTLY CENTERED OVER THE ARKLAMISS IS FORECAST BY SHORT TERM MODEL GUIDANCE TO SHIFT VERY LITTLE EAST AS WE GO THROUGH THE WEEKEND. THE RIDGE WILL ACT TO DEFLECT MINOR PERTURBATIONS AND KEEP THE AREA MOSTLY PRECIPITATION- FREE...HOWEVER CONVECTIVE PRECIPITATION DEVELOPING ON THE WESTERN PERIPHERY OF THE RIDGE COULD MANAGE TO SNEAK INTO EXTREME WRN/NRN PORTIONS OF THE FORECAST AREA LATER TODAY AND AGAIN SUNDAY --- ESPECIALLY IN THE AFTERNOON/EVNG AS REFLECTED BY GUIDANCE MOS POPS. A MID LEVEL SUBSIDENCE CAP WILL GREATLY LIMIT THE POTENTIAL FOR TSTMS IN ANY CASE OVER THE FORECAST AREA. FOG WILL CONTINUE TO BE A CONCERN THIS MORNING PRIMARILY SOUTH OF THE I-20....AND ESPECIALLY SUNDAY MORNING WHEN MID/HIGH LEVEL CLOUDINESS SHOULD NOT BE SO PREVALENT AND DISRUPTIVE OF NIGHTTIME COOLING. FORECAST PERSISTENCE SUGGESTS THAT DENSE FOG COULD DEVELOP AGAIN IN THE HBG AREA. OTHERWISE...LOOK FOR MORE OF THE SAME IN REGARD TO TEMPERATURES WITH WELL-ABOVE NORMAL READINGS (~ 15 DEG F) EXPECTED. /EC/ MONDAY THROUGH SATURDAY... A HIGHLY AMPLIFIED UPPER AIR PATTERN WILL BE IN PLACE ACROSS THE CONUS AT THE START OF NEXT WEEK COMPOSED OF A STRONG ANTICYCLONE OVER THE EASTERN SEABOARD AND A DEEP TROUGH ALONG THE CONTINENTAL DIVIDE. THE 00Z NWP GUIDANCE HAS DIFFERING OPINIONS AS TO HOW THIS PATTERN WILL EVOLVE AS WE HEAD INTO MID WEEK...LEAVING CONFIDENCE LOWER THAN USUAL FOR THIS TIME PERIOD. THE OP GFS AND GFS ENSEMBLE MEAN ARE FAIRLY SIMILAR WITH THEIR EVOLUTIONS SHOWING A CUT-OFF LOW DEVELOPING OVER THE SOUTH CENTRAL PLAINS LATE TUE INTO EARLY WED WHICH THEN TAKES ITS TIME TO SHIFT EAST AS THE MAIN BELT OF WESTERLIES REMAIN WELL NORTH. THE ECMWF MAINTAINS A LITTLE BETTER PHASING WITH THE POLAR JET UNTIL LATER IN THE WEEK WHEN A CUT-OFF LOW DEVELOPS OVER THE TN VALLEY AND GRADUALLY SHIFTS EAST. CONFIDENCE IS SOMEWHAT HIGHER IN THE SLOWER/EARLIER CUT-OFF SOLUTION OFFERED BY THE GFS/GEFS WHICH WILL KEEP HIGHER POPS AT BAY UNTIL A BIT LATER THAN OFFERED BY THE EURO. SHOWERS/THUNDERSTORMS MAY BEGIN IMPACTING AREAS WEST OF THE RIVER AS EARLY AS TUE AFTERNOON BUT FOR SURE BY TUE NIGHT AS SYNOPTIC LIFT AHEAD OF THE LOW BEGINS TO OVERSPREAD THE REGION. SLOW PROGRESSION OF THE UPPER LOW/DEEPLY SATURATED PROFILES/ UNIDIRECTIONAL SOUTHERLY FLOW IS GOING TO ENHANCE THE RISK FOR LOCALLY HEAVY RAINFALL AS THIS SYSTEM PASSES ALTHOUGH PINPOINTING WHERE EXACTLY THAT MIGHT BE IS TOUGH AT THIS JUNCTURE. THE RISK FOR SEVERE WEATHER IS GOING TO BE A BIG QUESTION MARK FOR THE SAME REASONS AS RESULTANT DEEP LAYER SHEAR REMAINS MARGINAL AT BEST. WILL CONTINUE TO HIGHLIGHT THE RISK FOR HEAVY RAINS/STRONG TO SEVERE THUNDER POTENTIAL IN THE HWO...BUT THE POTENTIAL FOR HEAVY RAINS ARE PROBABLY THE BIGGER CONCERN. THE DEEPER MOISTURE WILL SHIFT EAST LATE IN THE WEEK BRINGING A RETURN OF DRY WEATHER BY FRI/SAT. TEMPS WILL BE A BIT COOLER WED-SAT AS THE RAINS AND COOLER TEMPS MOVE IN...BUT ABOVE NORMAL TEMPS STILL EXPECTED LATE WEEK. ONLY OTHER ITEM OF NOTE IS THE POTENTIAL FOR SOME GUSTY SOUTH WINDS MON AND ESPECIALLY TUE AS THE LOW APPROACHES. ITS POSSIBLE SUSTAINED WINDS OF 20-25 MPH WITH GUSTS CLOSE TO 35 OR 40 MPH COULD DEVELOP PROMPTING THE NEED FOR A WIND ADVISORY(ESPECIALLY ACROSS THE DELTA) IF THIS UNFOLDS. /BK/ && .AVIATION...MORNING FOG/STRATUS WAS HOLDING SITES ALONG I-20 AND SOUTH TO IFR/LIFR CONDITIONS WHILE VFR CONDITIONS WERE BEING OBSERVED IN THE NORTH. THE FOG SHOULD BEGIN DISSIPATING AFTER 15Z AND VFR CONDITIONS SHOULD PREVAIL AREAWIDE BY 16Z. PERSISTENT SOUTHERLY FLOW WILL CONTINUE THE PROSPECTS FOR LATE NIGHT/EARLY MORNING STRATUS/FOG GOING INTO EARLY NEXT WEEK WITH VFR CONDITIONS EXPECTED TO PREVAIL DURING THE DAY. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 84 60 84 59 / 8 4 10 10 MERIDIAN 84 54 85 54 / 8 3 4 5 VICKSBURG 83 61 84 61 / 8 4 18 13 HATTIESBURG 84 59 85 58 / 8 9 9 7 NATCHEZ 82 64 82 63 / 8 4 22 12 GREENVILLE 82 61 83 62 / 9 4 14 19 GREENWOOD 84 61 86 62 / 12 4 9 13 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 17/EC/BK
AREA FORECAST DISCUSSION
NWS BILLINGS MT
956 AM MDT SAT MAR 17 2012 .SHORT TERM...VALID FOR TDY AND SUN... EASTERLY LOW-LEVEL FLOW IS IN PLACE OVER THE AREA AT 15 UTC THANKS TO 3-HOUR SURFACE PRESSURE FALLS ON THE ORDER OF 2 HPA THAT EXTEND FROM SHERIDAN NORTHWEST TO GREAT FALLS. THE 12 UTC NAM AND RUC ARE CONSISTENT IN SHOWING A SURFACE LOW DEEPENING OVER CENTRAL MT THIS AFTERNOON...WITH RELATIVELY IMPRESSIVE LOW- AND MID-LEVEL WARM AIR ADVECTION OVER SOUTHEASTERN MT AS A WARM FRONT RAPIDLY LIFTS NORTH IN STRENGTHENING SOUTHERLY FLOW. FORECAST SOUNDINGS SUGGEST MIXING TO 700 HPA AND MEAN WINDS IN THAT LAYER OF 25 TO 30 KT BEHIND THIS WARM FRONT IN PLACES LIKE SHERIDAN...BROADUS...AND MILES CITY. THE 850-HPA TEMPERATURES ARE EXPECTED TO APPROACH 20 C IN SOUTHEASTERN MT BY 00 UTC...SO HIGHS SHOULD NOT HAVE MUCH PROBLEM REACHING INTO THE UPPER 70S F. AN 80 F READING IS NOT OUT OF THE QUESTION IF THE THERMAL RIDGE DOES MAKE IT INTO THE BROADUS AREA BY 00 UTC. THOUGH DEWPOINTS ARE IN THE MID 30S F EVEN AT GILLETTE AS OF 15 UTC...THE SYNOPTIC EVOLUTION AND MIXING SHOULD BRING A SURGE OF VERY DRY AIR OUT OF WY AND INTO SOUTHEASTERN MT BY 00 UTC. THE RED FLAG WARNING THUS LOOKS ON TRACK. ONLY MINOR CHANGES WERE MADE TO THE FORECAST...MAINLY TO MAKE SOME SLIGHT ADJUSTMENTS TO WINDS. BOTH WINDS AND TEMPERATURES COULD END UP A BIT TOO LOW IN PLACES LIKE BILLINGS IF THE FURTHER WEST SURGE OF WARM AIR AND MIXING THAT THE 12 UTC RUC SUGGESTS IS CORRECT. WE DO NOT HAVE ENOUGH CONFIDENCE TO MAKE ANY DRASTIC MOVE TOWARD THAT SOLUTION AT THIS POINT THOUGH. SCHULTZ .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... THE EXTENDED BEGINS MONDAY WITH A DEEP NEGATIVELY-TILTED UPPER LEVEL TROUGH MOVING SLOWLY EASTWARD ACROSS THE REGION. STRONG QG FORCING AND FRONTOGENESIS BEHIND A SURFACE LOW IN EASTERN MONTANA COMBINE WITH SHORTWAVE ENERGY AND UPPER LEVEL DIVERGENCE TO PRODUCE PRECIP ACROSS THE REGION. FAIRLY STRONG COLD AIR ADVECTION WILL ALLOW THE PRECIP TO FALL AND ACCUMULATE AS SNOW IN THE FOOTHILLS AND MOUNTAINS WITH SEVERAL INCHES POSSIBLE. ACROSS FAR EASTERN MONTANA...THE PRECIP WILL FALL MAINLY AS RAIN WITH TEMPS MAINLY IN THE 40S. PRECIP BEGINS TO DISSIPATE OVERNIGHT MONDAY INTO TUESDAY AS DRY AIR WRAPS INTO THE REGION BEHIND THE DEPARTING SURFACE LOW AND THE FILLING UPPER LEVEL TROUGH. TEMPERATURES WILL REMAIN MAINLY IN THE 40S TO NEAR 50 ACROSS THE REGION TUESDAY. UPPER LEVEL RIDGING MOVES INTO THE REGION LATE TUESDAY AND REMAINS OVER THE AREA INTO THURSDAY. THIS WILL ALLOW TEMPERATURES TO WARM INTO THE 50S AND 60S BOTH WEDNESDAY AND THURSDAY. AT THE SAME TIME...THE SURFACE PRESSURE GRADIENT TIGHTENS UP ACROSS THE WEST IN RESPONSE TO HIGH PRESSURE STRENGTHENING UNDER THE RIDGE ACROSS THE CENTRAL ROCKIES. THIS WILL CAUSE SOUTHWEST WINDS TO INCREASE ACROSS WESTERN ZONES...ESPECIALLY IN THE FOOTHILLS FROM LIVINGSTON TO NYE. AS SUCH...INCREASED WINDS ACROSS THE WEST JUST A BIT TUESDAY NIGHT INTO EARLY THURSDAY. MODELS DIVERGE A BIT IN THEIR SOLUTIONS LATE THURSDAY INTO FRIDAY. THE ECMWF DRIVES A STRONG COLD FRONT THROUGH THE REGION LATE THURSDAY WITH PRECIP MAINLY CONFINED TO THE WESTERN MOUNTAINS. THE GFS FORECASTS A WEAK COLD FRONT TO MOVE INTO THE REGION FRIDAY...AT WHICH POINT IT STALLS ACROSS THE AREA THROUGH FRIDAY NIGHT. BOTH MODELS FORECAST A RETURN TO RIDGING ALOFT SATURDAY. DUE TO THE MODEL UNCERTAINTY...DID NOT MAKE ANY MAJOR CHANGES TO THE THURSDAY TO SATURDAY TIMEFRAME. STC && .AVIATION... SCATTERED RAIN AND HIGH ELEVATIONS SNOW SHOWERS WILL IMPACT OUR WEST TODAY AND TONIGHT...INCLUDING KLVM. EXPECT THE BEARTOOTH ABSAROKAS AND THE CRAZIES TO BE OBSCURED FREQUENTLY. VFR WILL PREVAIL AT ALL TAF SITES EXCEPT FOR LOCAL MVFR IN THE KLVM AREA DUE TO THE SHOWERS. THERE IS ALSO A SLIGHT RISK OF THUNDERSTORMS IN OUR WEST THIS AFTERNOON. EXPECT SOUTHERLY WINDS TO INCREASE ACROSS THE PLAINS THROUGH THE DAY WITH GUSTS OF 20-30 KTS BY AFTERNOON. JKL && .PRELIMINARY POINT TEMP/POPS... TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 070 042/065 034/045 028/049 031/060 036/062 035/058 2/W 13/W 66/O 21/B 01/B 11/B 10/B LVM 063 037/055 027/039 025/042 030/054 034/055 033/053 4/T 36/W 77/S 32/W 21/N 12/W 21/B HDN 074 041/070 032/047 027/050 029/062 033/064 031/061 1/B 12/W 46/O 31/B 01/B 11/B 10/B MLS 079 040/070 036/049 028/049 030/061 034/064 034/059 1/N 11/B 25/R 21/B 11/B 11/B 11/B 4BQ 077 044/074 036/051 027/049 030/062 034/066 034/060 1/N 01/N 25/R 21/B 11/B 11/U 10/B BHK 077 041/073 040/053 028/048 029/061 035/064 034/057 1/N 01/B 22/R 21/B 10/B 01/U 11/B SHR 075 039/070 033/046 024/045 027/060 030/062 031/056 1/N 12/W 36/O 31/B 01/B 11/B 10/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...RED FLAG WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR ZONES 130>133. WY...RED FLAG WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR ZONE 274. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
742 PM CDT SUN MAR 18 2012 .UPDATE... .DISCUSSION... WIND ADVISORY CONDITIONS SHOULD CONTINUE NEARLY UNABATED THIS EVENING AS THE LOW LEVEL JET INCREASES...A PACIFIC COLD FRONT PUSHES INTO THE PANHANDLE AND 985 MB LOW PRESSURE ACROSS WY LIFTS NORTH INTO WRN SD/ERN MT AND DEEPENS TO NEAR 980 MB TONIGHT. A HIGH WIND WARNING CONTINUES ACROSS WRN NEB AS THIS AREA IS MOST PRONE TO HIGH WIND GUSTS AND THE RUC SUGGESTED A 65KT 850 MB JET. THE RED FLAG WARNING HAS BEEN EXTENDED UNTIL 06Z AS EARLIER SOLNS OF THE RUC INDICATED VERY LOW RH...LESS THAN 25 PERCENT UNTIL 06Z BUT THE MODEL HAS SINCE BACKED OFF AS THE DRYLINE CONTINUES TO RETREAT WEST THROUGH KOGA. && .PREV DISCUSSION... /ISSUED 621 PM CDT SUN MAR 18 2012/ UPDATE... AVIATION... VFR IS EXPECTED WEST OF HIGHWAY 83 TONIGHT AND MONDAY. A POWERFUL PACIFIC COLD FRONT WILL MOVE EAST THROUGH THE FCST OVERNIGHT. ISOLATED STRONG OR SEVERE THUNDERSTORMS ARE POSSIBLE...MAINLY ALONG AND EAST OF HIGHWAY 83. MVFR CIGS MAY DEVELOP ALONG AND EAST OF HIGHWAY 83 TONIGHT THROUGH 15Z AHEAD OF THE COLD FRONT. VFR IS EXPECTED AFTER 15Z ALL AREAS. WINDS AT 18030G45KT WILL SUBSIDE TO BY ROUGHLY 06Z. PREV DISCUSSION... /ISSUED 325 PM CDT SUN MAR 18 2012/ SYNOPSIS... H5 HAND ANALYSIS THIS MORNING INDICATING A TROUGH OF LOW PRESSURE EXTENDING ALONG THE PACIFIC COAST FROM WASHINGTON TO SRN CALIFORNIA. HT FALLS WERE GREATEST OVER FAR SRN CA AND ARIZONA WITH 120 METER FALLS AT FLAGSTAFF AND 110 METER FALLS AT TUSCON. WINDS HAVE FINALLY BEGUN TO PICK UP ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON WITH OGALLALA GUSTING TO 45 MPH LAST HOUR AND IMPERIAL 43 MPH. RECORD HIGHS HAVE ALREADY BEEN SET AT IMPERIAL AND VALENTINE THIS AFTERNOON. AS OF 3 PM CDT...NORTH PLATTE TIED ITS RECORD OF 84 DEGREES. RED FLAG CONDS WERE BEING MET ACROSS ALL FIRE WEATHER FORECAST ZONES BUT 209 THIS AFTERNOON...AND WITH THE STRENGTH OF THE WINDS...GLAD WE HAVE A RED FLAG WARNING IN PLACE EVERYWHERE. DISCUSSION... NEAR TERM...TONIGHT THROUGH WEDNESDAY...FORECAST CHALLENGES THROUGH WEDNESDAY...DEAL WITH WIND AND CONVECTION TONIGHT...FIRE WEATHER CONCERNS TOMORROW...A COLD FROPA TOMORROW NIGHT...THEN THE THREAT FOR PRECIPITATION INTO WEDS AS A CLOSED UPPER LEVEL LOW MEANDERS ACROSS THE SRN PLAINS. FOR TONIGHT...WINDS AND THUNDERSTORM CHANCES WILL BE THE MAIN FORECASTING CONCERNS. WITH RESPECT TO WINDS...SURFACE LOW PRESSURE WILL DEEPEN ACROSS NERN WYOMING LATER THIS AFTERNOON AND THIS EVENING...THEN LIFT NORTH INTO SERN MT AND WRN ND OVERNIGHT. THE LOW LEVEL PRESSURE GRADIENT WILL STEEPEN EAST OF THE PANHANDLE LATE THIS AFTERNOON AND THIS EVENING...BEFORE RELAXING TOWARD MORNING...AS A SURFACE TROUGH TRANSITIONS EAST. H85 WINDS INCREASE TO 40 TO 60 KTS EAST OF THE PANHANDLE LATER THIS EVENING...PEAKING AROUND 06Z. IF WE COULD MIX THE BULK OF THIS OUT...THE HIGH WIND WARNING UNTIL 01Z MAY NEED TO BE EXTENDED THIS EVENING. H925 AND H85 WINDS ARE UNIDIRECTIONAL THROUGH ABOUT 03Z...THEN DIVERGE TOWARD LATE EVENING. THIS WOULD LESSEN MIXING AND LEAD TO SLIGHTLY LOWER BOUNDARY LAYER WINDS. FOR NOW...WILL LET THE HIGH WIND WARNING RIDE TILL 8 PM CDT AND LET THE EVENING CREW DECIDE ON WEATHER OR NOT TO EXTEND THE WARNING OR ISSUE A WIND ADVZY. POPS THIS EVENING WERE TRIMMED OUT OF THE WESTERN ZONES AND WILL BE CONFINED TO THE CENTRAL AND SERN ZONES THIS EVENING. THE CHANGE WAS MADE TO ACCOMMODATE THE DRY LINE POSITION WHICH IS ALREADY EAST OF HIGHWAY 83 AS OF 2 PM CDT. SLIGHT CHANCE POPS WERE RETAINED IN THESE AREAS IF CONVECTION DECIDES TO FIRE ALONG THE DRYLINE LATE THIS AFTERNOON. BETTER CHANCES FOR PRECIPITATION IN EASTERN AREAS WILL ARRIVE OVERNIGHT AS TSRAS FROM WRN KS LIFT NEWD INTO THE CENTRAL AND EASTERN ZONES. INITIATION FORCING IS MUCH MORE FAVORABLE IN WRN KS AND THE TX AND OK PANHANDLES THIS EVENING AND ANY STORMS IN THE ERN ZONES WILL HAVE TO ORIGINATE IN THESE AREAS. WITH TIMING BEING IN THE OVERNIGHT...SEVERE THREAT IS EXPECTED TO BE MINIMAL...THOUGH GUSTY WINDS MAY BE POSSIBLE INVOF OF ANY THUNDERSTORMS...THANKS TO DECENT H85 WINDS. FIRE WEATHER CONCERNS AND PRECIPITATION CHANCES IN THE EAST HIGHLIGHT THE MONDAY FORECAST. BY MONDAY AFTERNOON...THE DRYLINE WILL PUSH EAST OF HIGHWAY 83...WITH VERY LOW DEW POINTS NOTED WEST OF THIS FEATURE IN THE WRN SANDHILLS AND ERN PANHANDLE. EVEN WITH COOLER HIGHS IE. 60S...FCST DEW POINTS IN THE HIGH SINGLE DIGITS AND LOWER TEENS WILL LEAD TO MIN RH`S AROUND 15 PERCENT MONDAY AFTERNOON WHICH IS NEAR CRITICAL CRITERIA. WINDS WILL BE THE WILD CARD IN ALL OF THIS AS LIGHTER WINDS ARE EXPECTED WEST OF THE DRYLINE TOMORROW. GUIDANCE FOR OGA HAS AFTERNOON WINDS RANGING FROM 10 TO 20 KTS WHICH WOULD BE BLO RED FLAG CRITERIA. WINDS ARE A TAD HIGHER IN THE PANHANDLE AND ACTUALLY APPROACH 25 MPH BRIEFLY BY MID AFTERNOON. ATTM THE GREATEST THREAT FOR RFW CONDS IS IN THE EASTERN PANHANDLE...BUT NOT ENOUGH CONFIDENCE YET TO PUSH OUT A FIRE WEATHER WATCH. BY MONDAY NIGHT...A COLD FRONT WILL TRACK ACROSS THE FORECAST AREA...JOINING THE DRYLINE ACROSS EASTERN PORTIONS OF NEBRASKA. DECIDED TO HOLD ONTO SOME POPS IN EASTERN AREAS MONDAY EVENING EAST OF THE APPG FRONT AND INVOF OF THE DRY LINE...WITH DRY CONDS EXPECTED FURTHER WEST. H85 TEMPS WILL STRUGGLE TO GET OUT OF THE SINGLE DIGITS TUESDAY...WHICH WILL LEAD TO HIGHS IN THE 50S...AND WILL BE THE COOLEST DAY OF THE PERIOD. IRONICALLY...TUESDAY...WILL HAVE HIGH TEMPS AROUND OR SLIGHTLY ABOVE NORMAL. DRY CONDS WILL CARRY OVER INTO WEDNESDAY AS THE CENTRAL PLAINS ARE CAUGHT BETWEEN EXITING LOW PRESSURE TO THE NORTH AND A DEVELOPING CLOSED LOW OFF TO THE SOUTH. THE SECOND FEATURE WILL MEANDER...THEN DRIFT NORTH TOWARD THE END OF THE WEEK...POSING A PLETHORA OF FORECASTING ISSUES TO THE AREA WEDNESDAY NIGHT AND THURSDAY AS THIS SYSTEM DRIFTS NORTH INTO KANSAS AND SRN NEBRASKA. CONFIDENCE IN THE TRACK AND TIMING OF THIS FEATURE STILL IN DOUBT AS THE FORECAST MODELS HAVE ONLY RECENTLY HINTED AT THE DEVELOPMENT OF A DOWN STREAM BLOCKING RIDGE AND A NWD MOVING CLOSED LOW. LONG TERM...THURSDAY THROUGH SUNDAY...AS MENTIONED EARLIER...THE MODELS ARE TRENDING TOWARD A CUTOFF LOW CREEPING NORTH INTO KANSAS...THEN EAST INTO THE LOWER MISSOURI VALLEY LATE IN THE WEEK AND INTO THE WEEKEND. ON THIS TRACK...POPS WILL NEED TO BE INCREASED IN SOME CENTRAL...SRN AND EASTERN AREAS TO ACCOMMODATE PRECIPITATION DEVELOPMENT ON THE NORTHWESTERN PERIPHERY OF THE LOW. WENT AHEAD AND INTRODUCED POPS IN THE SOUTHEAST AND EASTERN ZONES FOR WEDS NIGHT THROUGH THURSDAY. BEYOND FRIDAY...DRY CONDS ARE EXPECTED AS RIDGING ALOFT BUILDS BACK INTO THE CENTRAL CONUS. TEMPS ARE EXPECTED TO BE BACK IN THE 70S BY THE WEEKEND. AVIATION... AVIATION CONCERNS THROUGH MONDAY DEAL WITH WINDS AS VISIBILITIES AND CEILINGS WILL REMAIN VFR. STRONG SOUTHERLY WINDS WILL CONTINUE INTO THE EVENING WITH GUSTS OF 45KTS OR HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING. DO EXPECT A DECREASE IN THE SPEEDS AFTER SUNSET...HOWEVER IT MAY BE AFTER MIDNIGHT BEFORE THE STRONG GUSTS DIMINISH. LOOK FOR THE WINDS TO FALL TO 12KTS OR LOWER AROUND DAYBREAK MONDAY...BUT WILL INCREASE AGAIN BY MID MORNING AS THE BOUNDARY LAYER MIXES...WITH SPEEDS OF 15 TO 20KTS AND GUSTS TO AROUND 25KTS...PRIMARILY EAST OF A LINE FROM KVTN TO KLBF. CONVECTION IS EXPECTED TO DEVELOP LATE THIS AFTERNOON OR EARLY EVENING ALONG THE DRYLINE OVER WESTERN KANSAS. THE TRAJECTORY OF ANY STORMS WILL BE NORTH NORTHEAST...SO THERE IS AN OUTSIDE CHANCE THAT LOCATIONS EAST OF A KIML TO KTIF TO KONL LINE COULD SEE STORMS THIS EVENING. THIS IS HIGHLY RELIANT ON WHERE CONVECTION DEVELOPS AND WITH LITTLE CONFIDENCE ON IT GETTING INTO THE LOCAL AREA HAVE NOT INCLUDED ANY RAIN...TS...OR CB IN THE TAF AT KLBF. FIRE WEATHER... FIRE CONCERNS WILL CONTINUE INTO THIS EVENING. WINDS ALOFT WILL BE ON THE INCREASE THROUGH THE REMAINDER OF THE AFTERNOON. AND WITH DEEP MIXING CONTINUING THROUGH EARLY EVENING...WILL CONTINUE TO GET THE STRONG WINDS BLOWING ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. WILL NOT BEGIN TO SEE RELATIVE HUMIDITY BEGIN TO RECOVER ABOVE CRITICAL LEVELS UNTIL AFTER SUNDOWN...SO RED FLAG WARNING WILL CONTINUE UNTIL THIS EVENING AS CONDITIONS REMAIN CRITICAL TO EXTREME FOR DANGEROUS FIRE BEHAVIOR. THE DRY AIR WILL STAY IN PLACE FOR MONDAY...ALTHOUGH TEMPERATURES WILL BE ABOUT 15 TO 20 DEGREES COOLER THAN TODAY. RELATIVE HUMIDITY WILL FALL TO AROUND 15 PERCENT IN LOCATIONS WEST OF HIGHWAY 83...HOWEVER WINDS IN THESE AREAS ARE EXPECTED TO BE LESS THAN 20KTS THROUGHOUT THE DAY. IN LOCATIONS TO THE EAST INTO CENTRAL NEBRASKA...WINDS WILL BE A BIT STRONGER /STILL 25KTS OR LOWER/ IN THE AFTERNOON...HOWEVER RELATIVE HUMIDITY WILL BE HIGHER AS WELL...25 TO 30 PERCENT. THEREFORE FIRE DANGER ON MONDAY IS NOT EXPECTED TO BE CRITICAL. && .LBF WATCHES/WARNINGS/ADVISORIES...HIGH WIND WARNING UNTIL MIDNIGHT MDT TONIGHT FOR NEZ004-022-023-035-056>058-069-094. RED FLAG WARNING UNTIL 1 AM CDT /MIDNIGHT MDT/ MONDAY FOR NEZ204- 210. WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ MONDAY FOR NEZ005>010-024>029-036>038-059-070-071. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
828 PM EDT SUN MAR 18 2012 .SYNOPSIS... HIGH PRESSURE CENTERED OFF THE EAST COAST WILL MAINTAIN A SOUTHERLY FLOW OF VERY WARM AIR OVER OUR AREA THROUGH THE COMING WEEK. AN UPPER LEVEL DISTURBANCE CROSSING THE REGION WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT AND MONDAY. QUIETER WEATHER RETURNS BY MIDWEEK AS RIDGING ALOFT BUILDS ACROSS THE REGION ONCE AGAIN. && .NEAR TERM /THROUGH MONDAY/... SHOWERS AND THUNDERSTORMS THAT FIRED ACROSS WESTERN NEW YORK EARLIER THIS AFTERNOON CONTINUE TO PUSH EAST INTO CENTRAL NEW YORK. JUST A FEW SCATTERED SHOWERS REMAIN JUST EAST OF LAKE ERIE AND SOUTHEAST OF LAKE ONTARIO. ACTIVITY IS WEAKENING WITH THE LOSS OF DAYTIME HEATING. MID LEVEL DISTURBANCE THAT HELPED TRIGGER THE STORMS EARLIER TODAY ACROSS WESTERN NEW YORK IS CENTERED OVER OHIO THIS EVENING. A FEW STRONG THUNDERSTORMS EXIST DIRECTLY BENEATH THIS DISTURBANCE. THROUGH THE NIGHT THE DISTURBANCE WILL LIKELY MAINTAIN ITSELF AS IT LIFTS NORTHEAST ACROSS WESTERN NEW YORK. HRRR AND HI-RES NMM SHOW SOME ACTIVITY SHIFTING ACROSS THE AREA LATER THIS EVENING WITH THE DISTURBANCE. WENT WITH CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. BETTER SHOT AT ACTIVITY FOR THE NIAGARA FRONTIER WITH THIS DISTURBANCE THAN EARLIER TODAY. THE LAKE SHADOW KEPT AREAS NORTHEAST OF ERIE STABLE. THE NORTH COUNTRY LOOKS TO HAVE A LOWER CHANCE OF ACTIVITY WITH THE DISTURBANCE REMAINING SOUTH OF LAKE ONTARIO. RISK OF FOG ALONG THE LAKESHORES AGAIN WILL BE A POSSIBILITY WITH PLENTY OF LOW LEVEL MOISTURE AND COOL LAKE TEMPERATURES. THE MID LEVEL DISTURBANCE LOOKS TO GET CAUGHT UNDERNEATH BUILDING RIDGE ALOFT MONDAY...WHILE WEAKENING AT THE SAME TIME. THIS MAKES THE CONVECTIVE POTENTIAL RATHER ILL DEFINED. THERE LOOKS TO BE SOME MID LEVEL CAPPING DEVELOPING...BUT WITH MODEST DIURNAL HEATING AND STILL PLENTY OF LOW LEVEL MOISTURE WITH SURFACE DEWPOINTS IN THE LOWER TO MID 50S A FAVORABLE THERMODYNAMIC PROFILE SHOULD DEVELOP...SUFFICIENT ENOUGH FOR SCATTERED AFTERNOON CONVECTIVE DEVELOPMENT. 850 MB TEMPERATURES IN THE +10C TO +12C RANGE SHOULD YIELD YET ANOTHER DAY OF RECORD OR NEAR RECORD TEMPERATURES MONDAY...WITH MOST HIGHS IN THE LOWER TO MID 70S...OR EVEN UPPER 70S. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... MONDAY NIGHT ANY SHOWERS OR THUNDERSTORMS ACROSS CENTRAL NY WILL END QUICKLY WITH THE LOSS OF DAYTIME HEATING. CONTINUED MILD AND WELL ABOVE SEASONAL NORMS FOR OVERNIGHT LOWS. TEMPERATURES MONDAY NIGHT WILL REMAIN IN THE 50S FOR MANY LOCALES WHICH IS SOME 20 TO 25 DEGREES ABOVE NORMAL. WITH THE WARM TEMPERATURES AND LINGERING LOW LEVEL MOISTURE PATCHY FOG MAY FORM AGAIN IN AREAS OF LIGHT WIND...AND ESPECIALLY WHERE RAIN FELL FROM PREVIOUS DAY SHOWERS AND THUNDERSTORMS. TUESDAY THE UPPER LEVEL RIDGE INCREASES AGAIN OVER THE EASTERN GREAT LAKES WITH VERY WARM TEMPERATURES EXPECTED. INCREASING SUNSHINE SHOULD DEEPEN THE MIXING LAYER AND MIX DOWN +10C AIR AT 850 HPA FOR HIGH TEMPERATURES WELL INTO THE 70S. COOLER NEAR THE LAKESHORES WHERE THE YET STILL COOL LAKES WILL DEVELOP A LAKE BREEZE CIRCULATION AND MAINTAIN HIGHS IN THE 60S ALONG THE LAKE SHORELINE. ALONG THESE LAKE BREEZE CIRCULATIONS AND OVER THE HIGHER TERRAIN OF THE SOUTHERN TIER...A STRAY SHOWER OR THUNDERSTORMS IS POSSIBLE AND WILL CARRY A LOW CHANCE POP FOR THIS ACTIVITY. IT WILL REMAIN VERY MILD TUESDAY NIGHT WITH SIMILAR OVERNIGHT LOWS AGAIN FALLING BACK INTO THE 50S. FOR THE BEGINNING OF SPRING...THE EASTERN RIDGE IS AT ITS STRONGEST ON WEDNESDAY WITH 12Z GFS SHOWING 583DM 500MB HEIGHT OVER WESTERN OH INTO THE EASTERN GREAT LAKES. WILL ALSO SEE THE WARMEST 850MB TEMPS AS A BROAD CHANNEL OF +12C AIR IS DUCTED NORTHWARD ON THE WEST FLANK OF THE RIDGE. ALTHOUGH THE LOWER LAYERS WILL HAVE MUCH WARMTH AND MOISTURE...THE MID AND UPPER LEVELS WILL BE DRY AND SUBSIDENT...SO DON`T EXPECT TO SEE MUCH MORE THAN SOME SHALLOW STRATOCU. HIGH TEMPS ON WEDNESDAY WILL REACH THE MID TO UPPER 70S...THE LOWER 80S POSSIBLE IN THE GENESEE RIVER VALLEY AND THE FINGER LAKES...AND MUCH COOLER ALONG THE IMMEDIATE LAKESHORE AREAS WITH A WELL ESTABLISHED LAKE BREEZE CIRCULATION. WEDNESDAY NIGHT WILL BE QUITE POSSIBLY THE WARMEST NIGHT OF THIS ANOMALOUS WEEK WITH OVERNIGHT LOWS NOT FALLING BELOW THE 50S REGIONWIDE...AND NOT BELOW THE MID 50S FOR MUCH OF THE REGION WEST OF THE FINGER LAKES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... BOTH 00Z ECMWF AND 12Z GFS ARE INDICATING A PSEUDO BACKDOOR COLD FRONT POISED TO DROP SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND SAINT LAWRENCE VALLEY BY THURSDAY NIGHT OR EARLY FRIDAY. THURSDAY WILL HAVE MORE CLOUD COVER AHEAD OF THIS FEATURE BUT MAINTAIN THE WARM AIR...THUS HIGH TEMPS WILL BE ONLY A COUPLE OF DEGREES OFF OF WEDNESDAY PEAK TEMPS...MID 70S AND EDGING TOWARD OR BREAKING THE 80 DEGREE MARK. CONTRARY TO THE GFS POPS DURING THE DAY ON THURSDAY... WILL HOLD OFF TO HAVE CHANCE POPS DURING THURSDAY NIGHT THROUGH FRIDAY MORNING. UPPER RIDGING PRECEDING THE APPROACHING CUTOFF LOW FROM THE CENTRAL PLAINS SHOULD BRING NIL POPS ON FRIDAY AFTERNOON AND NIGHT...THEN IT BECOMES QUITE QUESTIONABLE AS TO WHEN THE CUTOFF WILL ACTUALLY LIFT EASTWARD ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY. WILL GO WITH A BROADBRUSH OF CHANCE POPS SATURDAY AND SUNDAY. THE BRIGHT POINT IS THAT IT LOOK LIKE THE RETURN OF COLD AIR WILL REMAIN SEQUESTERED TO THE NORTH OR AT LEAST HOLD OFF UNTIL THE NEXT WEEK. HIGH TEMPS ON FRIDAY WILL BE IN THE MID 60S TO THE LOWER 70S...ON SATURDAY THE LOWER TO MID 60S...AND ON SUNDAY THE UPPER 50S TO LOWER 60S. OVERNIGHT LOWS WILL BE IN THE 40S FRIDAY AND SATURDAY NIGHTS. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... AREA OF CONVECTION PUSHING THROUGH THE REGION THIS EVENING WILL CONTINUE TO WEAKEN WITH LOSS OF DAYTIME HEATING. HOWEVER...MID LEVEL CIRCULATION ACROSS OHIO WILL MOVE NORTHEAST CREATING THE POTENTIAL FOR ADDITIONAL SCATTERED CONVECTION TONIGHT. THE POTENTIAL FOR FOG WILL ALSO EXIST OVERNIGHT WITH LIGHT WINDS AND INCREASING LOW LEVEL MOISTURE. LOCAL IFR VSBYS ARE LIKELY OVERNIGHT. MORNING FOG WILL LIFT BY MIDDAY MONDAY. HOWEVER...DIURNAL HEATING COMBINED WITH THE SLOW MOVING UPPER LEVEL DISTURBANCE WILL RESULT IN SCATTERED AFTERNOON CONVECTION. OUTLOOK... MONDAY NIGHT THROUGH FRIDAY...MAINLY VFR. && .MARINE... HIGH PRESSURE ENCOMPASSING THE EASTERN UNITED STATES WILL RESULT IN GENERALLY TRANQUIL CONDITIONS ON THE LAKES FOR THE COMING WEEK. THE MAIN CONCERN WILL BE TONIGHT INTO MONDAY WHEN AN UPPER LEVEL TROUGH WILL TRAVERSE THE REGION BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. AREAS OF FOG WILL AGAIN BE POSSIBLE TONIGHT AND MONDAY MORNING. && .CLIMATE... RECORD HIGHS...AND HIGH MINIMUMS FOR BUFFALO AND ROCHESTER THIS WEEK. BUFFALO DATERECORD HIGH (YEAR) HIGH MINIMUM (YEAR) MON 3/19 70 (1921) 58 (1903) TUE 3/20 74 (1903) 51 (1921) WED 3/21 69 (1913) 48 (1948) THU 3/22 71 (1938) 59 (1938) FRI 3/23 78 (1966) 48 (1920) ROCHESTER DATE RECORD HIGH (YEAR) HIGH MINIMUM (YEAR) MON 3/19 77 (1903) 58 (1903) TUE 3/20 79 (1903) 57 (1903) WED 3/21 72 (1921) 43 (1938) THU 3/22 83 (1938) 53 (1938) FRI 3/23 79 (1966) 50 (1938) MARCH OF 2012 MAY TURN OUT TO BE THE WARMEST MARCH ON RECORD. ITS NO SECRET THAT WE HAVE HAD ABOVE NORMAL TEMPERATURES THIS MONTH...WITH MOST OF WESTERN NEW YORK ALREADY RUNNING ABOUT 10 DEGREES ABOVE NORMAL. FOR THE NEXT WEEK...TEMPERATURES ARE FORECAST TO BE WELL ABOVE NORMAL AND BOTH BUFFALO AND ROCHESTER WILL HAVE MULTIPLE OPPORTUNITIES TO BREAK RECORD HIGHS...AND REMAIN ABOVE RECORD HIGH MINIMUMS DURING THIS PERIOD. WHILE MARCH IS HALF COMPLETE...IF FORECAST TEMPERATURES TURN OUT CORRECT...THERE WILL BE NEARLY A WEEK WITH TEMPERATURES AVERAGING ABOUT 25 DEGREES ABOVE NORMAL. PROJECTING THIS OUT...EVEN IF THE PAST FEW DAYS OF MARCH TURN OUT TO BE NEAR NORMAL...THERE IS A GOOD CHANCE THAT THE MONTHLY AVERAGE WILL TURN OUT TO BE BETWEEN 45 AND 48 DEGREES. THE WARMEST MARCH ON RECORD FOR BUFFALO IS 44.5 DEGREES SET IN 1946...AND FOR ROCHESTER 43.8 SET IN 1945. SO WHILE ITS A BIT EARLY TO PROCLAIM A RECORD...ITS BECOMING INCREASINGLY LIKELY THAT MARCH OF 2012 WILL BE RECORD SETTING. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...TMA NEAR TERM...SMITH/TMA SHORT TERM...WCH LONG TERM...WCH AVIATION...TMA MARINE...TMA CLIMATE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
705 PM EDT SUN MAR 18 2012 .SYNOPSIS... ABOVE NORMAL TEMPERATURES WILL PREVAIL MUCH OF THE UPCOMING WEEK AS AN UPPER RIDGE REMAINS AMPLIFIED OVER THE REGION. EACH AFTERNOON AND EARLY EVENING WILL BRING ISOLATED SHOWERS OR A THUNDERSTORM AS MOISTURE AND HEATING COMBINE WITH THE AFTERNOON SEA BREEZE FRONT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SUNDAY...IN THE VERY NEAR TERM...NARROW AXIS OF SFC BASED INSTABILITY EXITS ACROSS INLAND SC COUNTIES WHERE SOLAR INSOLATION WAS ONGOING THE LONGEST. VORT MAX WITH GOOD PRESENTATION IN BOTH SAT AND RADAR IMAGERY...JUST SOUTH OF CLT PROVIDING SOME SYNOPTIC SCALE LIFT GENERATING SOME MODERATELY STRONG CONVECTION. A FEW SPECIAL WEATHER STATEMENTS LIKELY IN THE OFFERING AND A STRAY SVR OR TWO NOT OUT OF THE QUESTION. HRRR INITIALIZED AT 15Z CAPTURED THESE STORMS PRETTY WELL AND TAKE THEM SSE THROUGH ABOUT 5 OR 6 PM. THE SAME MODEL IS NOT EXCITED ABOUT PRECIP CHANCES FURTHER NORTH WHERE EXTENSIVE STRATUS THROUGH EARLY AFTERNOON HELD DOWN HIGH TEMPS BY A FEW DEGREES COMPARED TO THE AFOREMENTIONED AREAS. IN FACT RUC ANALYSIS SHOWS THE BORDER BETWEEN SFC BASED CAPE AND CAPPING TO ROUGHLY FOLLOW THE STATE LINE. POPS NORTH OF THIS LINE ARE MORE PROBLEMATIC ESPECIALLY SINCE THE WELL INITIALIZED HRRR SHOWS NOTHING. HOWEVER CAPE FEAR REGION HAS ALSO CLEARED OUT NICELY OF CLOUD COVER AND 12Z WRF STILL IMPLIED SOME LIGHT QPF SO SOME SLIGHT CHANCE POPS WILL BE ADVERTISED THROUGH JUST AFTER 00Z AND PLACE LESS STRESS ON THUNDER. SHORTWAVE WILL BE EXITING THE COAST ROUGHLY BY THIS TIME AND SHOULD REPRESENT THE LAST REMAINING MECHANISM FOR LIFT AND THE OVERNIGHT HOURS LOOK MAINLY DRY. TEMP GUIDANCE HAS SOME DROPPING DEWPOINTS OVERNIGHT LEADING TO LOW TEMP FCST IN THE MID 50S FOR MOST OF THE AREA. THIS MAY BE A BIT TOO LOW AND HAVE RAMIFICATIONS FOR FOG POTENTIAL. FOR NOW FOLLOWED GUIDANCE RATHER CLOSELY AND ADVERTISED PATCHY FOG. LATER SHIFT MAY BE ABLE TO RE-EVALUATE BOTH AFTER CONVECTION DIES OFF. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...MONDAY AND TUESDAY TEMPERATURES WILL PAN OUT WELL ABOVE NORMAL FOR MIDDLE MARCH...AS AN UPPER RIDGE AXIS ALONG THE SOUTHERN AND CENTRAL APPALACHIANS AMPLIFIES. SEVERAL IMPULSES ALOFT WILL LIKELY DROP SE ALONG THE EAST SIDE OF THE RIDGE AXIS THE NEXT COUPLE DAYS TO PROVIDE SLIGHTLY ENHANCED LIFT. COUPLED WITH AFTERNOON HEATING...ADEQUATE COLUMN MOISTURE...AND THE SEA BREEZE CIRCULATION...WARRANTS ISOLATED CONVECTION BOTH MONDAY AND TUESDAY. UPPER 70S TO MID 80S EXPECTED BOTH DAYS WITH 60S ALONG THE IMMEDIATE COASTAL SITES. LOWS GENERALLY 50S AREA-WIDE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...LOW CONFIDENCE FORECAST WITH MEDIUM RANGE GUIDANCE STILL HAVING TROUBLE OUT WEST. DEEP 5H TROUGH OVER THE SOUTHWEST CONUS WILL EVENTUALLY CUTOFF OVER TX MIDWEEK. MAIN FORECAST ISSUE IS FIGURING HOW FAR NORTH THE CUTOFF OVER TX WILL LIFT BEFORE MOVING EAST. CLOSER TO HOME THE SUMMER PATTERN CONTINUES WITH BERMUDA HIGH HOLDING UNDER 5H RIDGE. THE BREAKDOWN OF THE 5H RIDGE WILL DETERMINE HOW FAR NORTH THE CUTOFF TRAVELS BEFORE IT MOVES EAST. A STRONGER 5H RIDGE THAN WHAT THE GUIDANCE IS SHOWING...A KNOWN BIAS...WOULD TEND TO TRACK THE LOW FARTHER NORTH WHILE ALSO RESULTING IN A SLOWER SOLUTION. GIVEN THE LOW CONFIDENCE AND THE ISSUES THE GUIDANCE HAS BEEN HAVING WITH SOUTHWEST SYSTEMS THIS WINTER DID NOT MAKE A LOT OF CHANGES TO PREVIOUS FORECAST. HIGHEST POP LOOKS TO BE SAT/SAT NIGHT WHEN STACKED LOW AND ASSOCIATED COLD FRONT IMPACT THE REGION. OTHERWISE HAVE DIURNAL SLIGHT CHANCE POP EACH DAY TO ACCOUNT FOR AFTERNOON CONVECTION. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...IN THE NEAR TERM...CONVECTION IS WINDING DOWN WITH WARMING CLOUD TOPS. EXPECTED LIGHT SHOWERS TO BE NEAR ILM AND CRE...OTHERWISE TONIGHT`S PRECIP IS ABOUT OVER. SOME UNCERTAINTY WITH RESPECT TO STRATUS. CEILINGS AND VIS ARE LIFR ALONG THE IMMEDIATE COAST...WITH IFR CEILINGS INLAND A BIT. EXPECT IFR TO BE IN FOR THE ENTIRE NIGHT ALONG THE COAST...BECOMING IFR AT THE INLAND TERMINALS TOWARD MIDNIGHT. MONDAY...A SLOW IMPROVEMENT IS EXPECT BY MID MORNING...WITH VFR EXPECTED BY LATE MORNING. SOME SCATTERED CONVECTION IS POSSIBLE AGAIN IN THE AFTERNOON WITH AN AIRMASS SIMILAR TO TODAY. EXTENDED OUTLOOK...THROUGH THE PERIOD...MORNING FOG/MVFR...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE AFTERNOON...THROUGH FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SUNDAY...WEAK BOUNDARY STALLED ALONG FRYING PAN SHOALS LOSING ITS IDENTITY ESPECIALLY ALONG THE IMMEDIATE COAST WHERE SEA BREEZE IS DEVELOPING. IN THE WAKE OF THIS FEATURE A VERY WEAK GRADIENT WILL REMAIN IN PLACE ACROSS THE COASTAL WATERS WITH RATHER LIGHT AND VARIABLE FLOW ACROSS NORTHERN ZONE OR TWO. A LIGHT WIND CONTAINING A SOUTHERLY COMPONENT...I.E. SW TO WSW...WILL BE MAINTAINED OVER SOUTHERN WATERS. WITH SUCH LIGHT WINDS AND IN THE ABSENCE OF ANY SIGNIFICANT SWELL ENERGY SEAS WILL BE CAPPED AT 2 FT FOR THE MOST PART. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...LIGHT AND SOMEWHAT VARIABLE ONSHORE WINDS WILL PREVAIL MONDAY AND TUESDAY...KEEPING SEAS RELATIVELY SMALL FOR MIDDLE MARCH AND QUITE MANAGEABLE. ESSENTIALLY WE CAN EXPECT 2-3 FOOT SEAS...PRIMARILY SE WAVES OF 1-3 FEET EVERY 78 SECONDS AND ALIGHT S-SE CHOP ON THE WATERS. ISOLATED SHOWERS AND THUNDERSTORMS SHOULD BE EXPECTED MAINLY IN THE LATE AFTERNOONS AND OVERNIGHT BOTH ACROSS WESTERN EDGE OF THE GULF STREAM...AND POSSIBLY INSHORE AS ISOLATED LATE DAY STORMS DRIFT OFF LAND TOWARD THE S OR SE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 PM SUNDAY...SOUTH TO SOUTHEAST FLOW AROUND BACKSIDE OF BERMUDA HIGH WILL CONTINUE FOR MUCH OF THE PERIOD. GRADIENT REMAINS FAIRLY WEAK THROUGH THE PERIOD WITH ONLY A SLIGHT TIGHTENING LATER FRI...ASSUMING THE TIMING FOR THE SYSTEM EMERGING FROM THE SOUTHWEST IS CORRECT. SPEEDS WILL GENERALLY BE 10 TO 15 KT WITH A SLIGHT INCREASE EACH AFTERNOON AS THE SEA BREEZE DEVELOPS. ALTHOUGH WINDS WILL BE RELATIVELY LIGHT THE PROLONGED RETURN FLOW AROUND THE BERMUDA HIGH WILL DEVELOP A 7 TO 8 SECOND SOUTHEAST SWELL BETWEEN 2 TO 3 FT ON TOP OF THE 1 TO 2 FT WIND WAVE BEING GENERATED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...MBB SHORT TERM...MJC LONG TERM...III AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
454 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK SURFACE TROUGH MEANDERING ACROSS THE REGION WILL BRING ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND AND INTO MONDAY. OTHERWISE...ABOVE NORMAL TEMPERATURES WILL PREVAIL THROUGH MUCH OF NEXT WEEK...AS AN UPPER RIDGE OVER THE REGION AMPLIFIES. && .UPDATE /TONIGHT/... AS OF 450 PM SATURDAY...AFTER SPEAKING WITH A REPRESENTATIVE OF NC FORESTY WE HAVE ISSUED A DENSE SMOKE ADVISORY FOR INLAND PORTION OF BRUNSWICK COUNTY FROM 8 PM THIS EVENING UNTIL 10 PM SUNDAY. A GROUND FIRE IN THE GREEN SWAMP IS STILL PRODUCING COPIOUS AMOUNTS OF SMOKE...WHICH SHOULD BECOME TRAPPED BY A STRONG TEMPERATURE INVERSION TONIGHT. WE ARE EXPECTING VERY LOW VISIBILITIES TO DEVELOP ALONG PORTIONS OF HIGHWAY 211 (GREEN SWAMP ROAD) IN NORTHWESTERN BRUNSWICK COUNTY...WHERE SEVERAL VEHICLE ACCIDENTS WERE REPORTED LAST NIGHT. NO OTHER CHANGES AT THIS TIME. -TRA && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...EAST-WEST BOUNDARY SEPARATING NRLY AND SRLY WINDS VERY ROUGHLY BISECTING THE REGION RIGHT NOW/CLOSE TO THE STATE LINE. RUC ANALYSIS SUGGESTS THIS BOUNDARIES VERTICAL IDENTITY EXTENDS TO ABOUT 925MB OR 3KFT. HIGHER DEWPOINTS AND LOWER LCLS CONTINUE TO BE FOUND TO THE NORTH OF THIS BOUNDARY BUT ALAS CU FIELDS CONTINUE TO BE MINIMAL. RADAR PRESENTATION OF SEA BREEZE ALSO SUGGESTS A DEPTH OF ABOUT 3KFT. IN THE ABSENCE OF SYNOPTIC SCALE LIFT NEITHER OF THESE ARE GOING TO BE TERRIBLY EFFECTIVE IN LEADING TO CONVECTION WITH LFCS CURRENTLY CLOSER TO 6KFT. THIS SYNOPTIC ASCENT THOUGH GENTLE WILL BE PROVIDED BY THE SHORTWAVE CURRENTLY COMING OUT OF EASTERN TN. THERE IS STILL A SHORT WINDOW OF OPPORTUNITY FOR CONVECTION TODAY FROM ABOUT 20 OR 21 UTC THROUGH SUNDOWN AT WHICH TIME ANY COVERAGE OF STORMS WILL QUICKLY RUN OUT OF DIURNALLY DRIVEN INSTABILITY. AS SEEN LAST NIGHT HOWEVER IT IS DIFFICULT TO GO WITH A COMPLETELY DRY OVERNIGHT FORECAST IN LIGHT OF A TRAILING 10 S-1 VORT OR TWO STILL PROGGED TO MOVE ACROSS. THUS-20 POPS CARRIED OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...A WEAK E-W SURFACE BOUNDARY WILL MEANDER SOUTHWARD OVER OUR FORECAST ZONES ON SUNDAY. DESPITE REMAINING BENEATH AN UPPER RIDGE...ENOUGH COLUMN MOISTURE AND INSTABILITY WILL EXIST TO MAINTAIN ISOLATED SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY. IT SHOULD BE NOTED THE ENVIRONMENTAL WIND FIELD WILL REMAIN UNIMPRESSIVE AND ANY STORMS THAT FORM WILL FAVOR SURFACE HEATING AND WILL LIKELY EXHIBIT PULSE CHARACTERISTICS. BY MONDAY WE MAY SEE THE BOUNDARY LIFTING BACK NORTH. MOISTURE AND INSTABILITY REMAIN SIMILAR AND HAVE EXTENDED ISOLATED POP VALUES INTO MONDAY. GIVEN THE EXCESSIVE WARMTH...SEA-BREEZE CONVERGENCE MAY ALSO PLAY A ROLE INITIATING CONVECTION SUNDAY AND MONDAY IN THE AFTERNOON AND EARLY EVENINGS. MILD TEMPERATURES WILL PREVAIL BOTH DAYS BENEATH THE THERMAL RIDGE...JUST A FEW DEGREES COOLER ACROSS THE NORTHERN ZONES SUNDAY BEHIND THE FRONT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...DEEP 5H TROUGH OVER THE SOUTHWEST...A FAMILIAR SIGHT THIS YEAR...AT THE START OF THE PERIOD PROVIDES PLENTY OF UNCERTAINTY IN THE LONG RANGE PERIOD. MEDIUM RANGE GUIDANCE IN DECENT AGREEMENT ON THE TROUGH TURNING INTO A 5H CUTOFF...BUT LITTLE ELSE. TIMING REMAINS A BIG QUESTION AS SURFACE AND UPPER RIDGING ALONG THE EAST COAST IS SURE TO HOLD STRONGER THAN GUIDANCE INDICATES...MEANING THE MEDIUM RANGE SOLUTIONS ARE ALL LIKELY TOO FAST MOVING THE 5H TROUGH/CUTOFF LOW EAST. HPC IS ALSO FAVORING A SLOWER SOLUTION. THE END RESULT WILL BE A SUMMER-LIKE PATTERN WITH STRENGTHENING 5H RIDGE AND BERMUDA HIGH. DIURNAL/SEA BREEZE CONVECTION MAY DEVELOP TUE/WED BUT BUILDING 5H RIDGE AS THE UPPER TROUGH/LOW MOVES EAST WILL HELP SUPPRESS UPWARD MOTION THU AND MAYBE FRI DEPENDING ON HOW SLOW THE TROUGH/LOW MOVES EAST. COLD FRONT MOVING INTO THE REGION LATE IN THE PERIOD WILL PROVIDE THE BEST CHANCES FOR WIDESPREAD PRECIP. AREA OF DEEP MOISTURE AHEAD OF THE FRONT IS LIMITED AND IT LOOKS LIKE THE BEST DYNAMICS PASS TO THE NORTH. GIVEN THE UNCERTAINTY AND THE MARGINAL CONDITIONS DO NOT FEEL ANYTHING MORE THAN A LOW CHANCE POP IS WARRANTED. TEMPERATURES WILL RUN ABOVE TO WELL ABOVE CLIMO WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE MID 50S. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 19Z...TERMINALS ARE VFR THIS AFTERNOON. SKIES ARE GENERALLY SCATTERED...AND CUMULUS HAS JUST BEGUN TO DEVELOP. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH TODAY. A PIEDMONT TROUGH WILL EXIST FROM KLBT TO KFLO AND A SEA BREEZE WILL DEVELOP AND MOVE SLIGHTLY INLAND OF THE COASTAL TERMINALS LATER THIS AFTERNOON. SUFFICIENT INSTABILITY WILL EXIST NEAR THESE FOCUS AREAS FOR ISOLATED TO WIDELY SCATTERED SHOWERS TO OCCUR THROUGH MUCH OF THIS TAF VALID PERIOD. ISOLATED THUNDERSTORMS WILL ALSO DEVELOP ONCE THE CONVECTIVE TEMPERATURE IS REACHED OVER THE NEXT SEVERAL HOURS. CONFIDENCE IS HIGHEST THAT THUNDERSTORMS WILL OCCUR NEAR THE KILM AND KLBT TERMINALS LATER THIS AFTERNOON WITH TEMPO MVFR/IFR POSSIBLE. OTHERWISE...MAINLY SHOWERS CAN BE EXPECTED. VFR CAN BE EXPECTED OUTSIDE OF SHOWERS AND THUNDERSTORMS. DUE TO THE PROXIMITY OF THE FRONT PRECIPITATION SHOULD LINGER THROUGH MUCH OF THE EVENING AND OVERNIGHT HOURS. WINDS WILL BE SOUTHWEST TODAY 5-10 KNOTS...BECOMING SOUTH AT THE COASTAL TERMINALS IN THE NEXT SEVERAL HOURS DUE TO THE SEA BREEZE. THIS EVENING AND OVERNIGHT WINDS WILL LIKELY BECOME LIGHT SOUTHWEST AT THE SOUTHERN TERMINALS AND LIGHT AND VARIABLE AT KILM AND KLBT. AT KILM AND KLBT THERE IS A GOOD CHANCE FOR IFR STRATUS TO DEVELOP... WHILE MVFR VISIBILITIES WILL BE MOST LIKELY AT THE REMAINING TERMINALS. EXPECT MVFR CONDITIONS OR GREATER 14-16Z WITH SHOWERS DEVELOPING. EXTENDED OUTLOOK...THROUGH THE PERIOD...MORNING FOG/MVFR...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE AFTERNOON...THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...WINDSHIFT BOUNDARY WILL BE LURKING NOT TOO FAR TO THE NORTH OF THE AREA FOR MOST OF THE PERIOD. THIS BOUNDARY HAS MADE MORE SOUTHERN PROGRESS OVER LAND THAN OVER WATER AND THIS WILL LIKELY HOLD TRUE OVERNIGHT. THIS WILL PRECLUDE ANY NORTHERLY WIND COMPONENT FROM ENTERING THE FORECAST AREA ALTHOUGH NORTHERN ZONES MAY GO VERY LIGHT AND VARIABLE AS A RESULT OF HE PROXIMITY OF THE TROUGH. LIGHT S TO SWRLY FLOW CAPPED AT 10 KTS WILL REMAIN IN PLACE ELSEWHERE AS WEAK BERMUDA HIGH PRESSURE CONTINUES TO BE THE DOMINANT WIND MAKER. SEAS REMAINING RELATIVELY DIMINUTIVE AT 2 TO 3 FT. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...BY DAYBREAK SUNDAY NE WINDS WILL PREVAIL N OF CAPE FEAR AS AN E-W FRONTAL BOUNDARY SLIPS SLOWLY SOUTHWARD. WIND SPEEDS WILL HOLD BELOW 20-25 KNOTS SO ADVISORIES WILL NOT BE NEEDED. THE FRONT MAY NOT MAKE IT TO WINYAH BAY LATE SUNDAY AND COULD MOVE BACK NORTH SUNDAY NIGHT INTO MONDAY. THUS WE MAY VERY WELL SEE A VARIABLE WIND DIRECTION SUNDAY AND MONDAY WITH LIGHT SPEEDS OVERALL. NO PROBLEMS WITH SEAS...ESSENTIALLY 2-3 FT IN A MIX OF SE WAVES AND SHORTER PERIOD SSW WIND CHOP. THE WEAK FRONTAL BOUNDARY MAY TRIP OFF ISOLATED TSTMS NEAR OR OVER THE WATERS. MARINERS SHOULD CONSULT RADAR TRENDS BEFORE HEADING OUT SUNDAY AND MONDAY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...MAJORITY OF THE PERIOD WILL BE MARKED BY SOUTH TO SOUTHEAST WINDS AT OR BELOW 10 KT. BERMUDA HIGH WILL BE THE MAIN FEATURE THOUGH LATE IN THE PERIOD A COLD FRONT WILL APPROACH FROM THE WEST. TIMING OF THE COLD FRONT REMAINS A BIG QUESTION...BUT EVEN THE FASTEST SOLUTION KEEPS THE FRONT TO THE WEST THROUGH THU EVENING. THE FASTER SOLUTION DOES LEAD TO A PINCHED GRADIENT THU WHICH WOULD PUSH SOUTHERLY FLOW CLOSE TO 20 KT. HOWEVER THE SLOWEST AND THE FASTEST SOLUTION IS FAVORED. SO WHILE THERE MAY BE A MARGINAL INCREASE IN SPEEDS THU AS GRADIENT TIGHTENS A LITTLE SPEEDS SHOULD REMAIN UNDER 15 KT. SEAS WILL RUN 2 TO 3 FT TUE INTO WED BUT A BUILDING EAST TO SOUTHEAST SWELL LATE IN THE PERIOD WILL PUSH SEAS INTO THE 3 TO 5 FT RANGE THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...DENSE SMOKE ADVISORY FOR INLAND BRUNSWICK 8 PM SATURDAY UNTIL 10 AM SUNDAY. MARINE...NONE. && $$ NEAR TERM...MBB/TRA SHORT TERM...MJC LONG TERM...III AVIATION...MRR/MBB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK BACK DOOR COLD FRONT WILL SETTLE SOUTH THROUGH CENTRAL NC THROUGH TONIGHT. HIGH PRESSURE WILL FOLLOW AND RIDGE INTO NC FROM THE COASTAL MIDDLE ATLANTIC REGION THROUGH SUNDAY. && .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 315 PM SATURDAY... THROUGH EARLY TONIGHT: A SURFACE TROUGH/WEAK BACK DOOR COLD FRONT STRETCHED AT 18Z FROM NEAR KMRH-KSOP-KEXX...WHILE THE MORE NOTICEABLE COOLING RELATIVE TO TEMPERATURES OF FRI HAVE BEEN FOCUSED OVER NORTHEASTERN NC/SOUTHEASTERN VA OWING TO A MORE ONSHORE COMPONENT OF THE LOW LEVEL FLOW OFF OF COOL MIDDLE ATLANTIC COASTAL WATERS. THIS TRAILING MARITIME PUSH...ASSOCIATED ENHANCED CUMULUS FIELD PER VISIBLE SATELLITE IMAGERY...AND LOCATION OF A H85 TROUGH AXIS PER REGIONAL VWP DATA...WILL LIKELY MARK THE APPROXIMATE NORTHEASTWARD BOUND FOR THE POTENTIAL FOR DEEP CONVECTIVE DEVELOPMENT THIS AFTERNOON. ISOLATED TO SCATTERED CONVECTION WILL REMAIN POSSIBLE THROUGHOUT CENTRAL NC THIS AFTERNOON...GIVEN THE PRESENCE OF THESE TWO CONVERGENCE-FOCUSING BOUNDARIES AMIDST DEVELOPING WEAK TO MODERATE BOUNDARY LAYER (BL)-BASED INSTABILITY PER MODIFIED 12Z PROXIMITY RAOBS FOR REPRESENTATIVE BL PARCELS OF UPPER 70S-LOWER 80S TEMPERATURES OVER 50 TO 60 DEGREE DEWPOINTS...FROM NW TO SE. ALOFT...A PAIR OF VORTICITY MAXIMA STRETCHED FROM THE SC UPSTATE TO WEST-CENTRAL NC -- THE FORMER APPARENT ON SATELLITE IMAGERY AND MUCH STRONGER PER RUC MID LEVEL VORTICITY ANALYSES -- WILL DRIFT EASTWARD IN WEAK (10-15 KTS) WESTERLY MID LEVEL STEERING FLOW. THESE FEATURES MAY FOCUS CONVECTION FROM CENTRAL SC TO SE NC THIS AFTERNOON. STORMS HAVE ALSO ALREADY FIRED ON THE EAST-FACING SLOPES OF THE NC/VA BLUE RIDGE...AND THE CONVECTIVE ALLOWING MODELS (CAMS) CONTINUE TO INDICATE THE POTENTIAL FOR THESE TO PROPAGATE ON THEIR CONGLOMERATE OUTFLOWS -- AND WITH THE AFOREMENTIONED WEAK MID LEVEL STEERING FLOW -- EASTWARD INTO THE WESTERN PIEDMONT THROUGH EARLY THIS EVENING. SOME OF THIS ACTIVITY MAY CONTINUE EASTWARD ACROSS THE REMAINDER OF CENTRAL NC OVERNIGHT...THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO CARRY MORE THAN A SLIGHT TO LOW CHANCE POP INTO THE NIGHT TIME HOURS. MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC...WHICH HAS ALREADY SUPPORTED AN EXPANSIVE AREA OF MARINE STRATUS AND FOG ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...WILL PROMOTE THE DEVELOPMENT OF LOW STRATUS AND FOG FROM NE TO SW ACROSS THE CWFA BETWEEN 04-10Z. GIVEN A LACK OF APPRECIABLE CAA EXCEPT OVER THE FAR NORTHEAST...LOWS WILL BE SIMILAR TO PREVIOUS NIGHTS - 52 TO 58... COOLEST NORTHEAST. SUN AND SUN NIGHT: LOW STRATUS AND FOG WILL SLOWLY LIFT AND BURN OFF DURING THE MORNING AND MIDDAY HOURS...BUT SCT TO BKN 2000-3500 FT CLOUDS WILL LIKELY LINGER THROUGHOUT THE AFTERNOON. ANY PARTIAL CLEARING LATE IN THE DAY AND DURING THE EVENING WILL THEN CAUSE AREAS OF FOG AND/OR STRATUS TO REDEVELOP OVERNIGHT INTO EARLY MON. THE CLOUDS AND MORE NOTICEABLY COOLER AIR MASS (ONCE THE NORTHEASTERLY TO EASTERLY FLOW FULLY ENCOMPASSES CENTRAL NC TONIGHT)...SHOULD HOLD TEMPS IN THE 71 TO 78 DEGREE RANGE FROM VA TO SC STATE BORDERS. THE COOLER TEMPS AND RESULTANT WEAK INSTABILITY... AND ANTICYCLONIC FLOW IN HIGH PRESSURE RIDGING SOUTHWARD FROM THE COASTAL MIDDLE ATLANTIC (AND TO THE NORTH OF THE WEAK BACK DOOR FRONT FORECAST TO STALL/WASH OUT OVER SC SUN)...SHOULD RESULT IN LESSER CHANCES FOR CONVECTION THAN PREVIOUS DAYS. NONETHELESS...THE CONTINUED PRESENCE OF A MID LEVEL SHEAR AXIS THAT EARLIER SAT WAS ANALYZED FROM THE OH VALLEY TO THE NC COAST...AND APPROACH PASSAGE OF A SOUTHERN STREAM DISTURBANCE OVER MO THIS AFTERNOON...WARRANTS A SLIGHT CHANCE OF SHOWERS...MAINLY WITH HEATING SUN AFT-EVE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 305 PM... RIDGE ALOFT OVER THE EASTERN UNITED STATES WITH SURFACE HIGH PRESSURE OFFSHORE. WEAK WINDS...PRECIPITABLE WATERS NEAR ONE INCH AND MINIMAL INSTABILITY AND POTENTIAL ENERGY SUGGESTS NO MORE THAN A ONE IN FIVE CHANCE FOR MEASURABLE RAIN... DIURNALLY DRIVEN BY AFTERNOON HEATING. LOW LEVEL THICKNESSES 25 TO 30 METERS ABOVE NORMAL WITH SOME MINIMAL REDUCTION IN INSOLATION BY CLOUDS DURING THE AFTERNOON. AFTERNOON HIGH TEMPERATURES 76 TO 81. LOW TEMPERATURES IN THE MID TO UPPER 50S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 305 PM... DEEP SLOWLY PROGRESSING TROUGH OR CUT OFF LOW OVER TEXAS WEDNESDAY MORNING ATTEMPTS TO REACH THE CAROLINAS LATE IN THE PERIOD... ALTHOUGH THE EAST COAST RIDGE RESISTS. MODEL SPREAD IN SOLUTIONS REDUCES CONFIDENCE... AS DOES LACK OF DECENT RUN TO RUN CONTINUITY WITHIN MODELS. MODELS FREQUENTLY TOO FAST WITH CUT OFF LOWS AND WILL FAVOR THE SLOWER GFS TIMING... THOUGH THIS MAY ALSO BE TOO FAST. WILL CONTINUE LOW CHANCES FOR MAINLY AFTERNOON SHOWERS OR A THUNDERSTORM FROM PREVIOUS DAYS INTO MID WEEK WITH RAIN CHANCES RISING TO 30 TO 40 PERCENT FOR FRIDAY AND SATURDAY AS WINDS ALOFT BEGIN TO INCREASE. AFTERNOON HIGH TEMPERATURES IN THE MID 70S. LOW TEMPERATURES MID AND UPPER 50S. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... AS OF 210 PM SATURDAY... VFR CONDITIONS...OUTSIDE OF SCATTERED SHOWERS AND STORMS MAINLY THROUGH THIS EVENING...WILL CONTINUE THROUGH EARLY TONIGHT. THESE CONDITIONS WILL THEN DETERIORATE TO IFR CEILINGS AND MVFR-IFR VISIBILITIES FROM NE TO SW BETWEEN 04-10Z...OWING TO MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC. INDEED...AN EXPANSIVE AREA OF MARINE STRATUS AND FOG HAD ADVECTED ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...AND THIS IS THE AIR MASS THAT WILL CONTINUE SOUTHWESTWARD AND CAUSE THE DETERIORATING AVIATION CONDITIONS ACROSS CENTRAL NC OVERNIGHT. CONDITIONS WILL GRADUALLY IMPROVE WITH HEATING ON SUNDAY...WITH VISIBILITIES BECOMING VFR AND CEILINGS LIFTING TO MVFR BETWEEN 13-16Z. LOOKING BEYOND 18Z SUNDAY: SCT TO BKN 2000-3500 FT CLOUDS WILL LINGER THROUGHOUT THE AFTERNOON SUN...AND ANY PARTIAL CLEARING LATE IN THE DAY AND DURING THE EVENING WILL CAUSES AREAS OF FOG AND/OR STRATUS TO REDEVELOP OVERNIGHT INTO EARLY MON. MORNING FOG OR STRATUS AND SCT TO BKN AFTERNOON CONVECTIVE CLOUD BASES GENERALLY BETWEEN 2500-3500 FT...AND ASSOCIATED ISOLATED TO WIDELY SCATTERED CONVECTION...WILL THEN RULE THROUGH THE MIDDLE OF THE WORK WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM... LONG TERM... AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
306 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK BACK DOOR COLD FRONT WILL SETTLE SOUTH THROUGH CENTRAL NC THROUGH TONIGHT. HIGH PRESSURE WILL FOLLOW AND RIDGE INTO NC FROM THE COASTAL MIDDLE ATLANTIC REGION THROUGH SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM SATURDAY... THROUGH EARLY TONIGHT: A SURFACE TROUGH/WEAK BACK DOOR COLD FRONT STRETCHED AT 18Z FROM NEAR KMRH-KSOP-KEXX...WHILE THE MORE NOTICEABLE COOLING RELATIVE TO TEMPERATURES OF FRI HAVE BEEN FOCUSED OVER NORTHEASTERN NC/SOUTHEASTERN VA OWING TO A MORE ONSHORE COMPONENT OF THE LOW LEVEL FLOW OFF OF COOL MIDDLE ATLANTIC COASTAL WATERS. THIS TRAILING MARITIME PUSH...ASSOCIATED ENHANCED CUMULUS FIELD PER VISIBLE SATELLITE IMAGERY...AND LOCATION OF A H85 TROUGH AXIS PER REGIONAL VWP DATA...WILL LIKELY MARK THE APPROXIMATE NORTHEASTWARD BOUND FOR THE POTENTIAL FOR DEEP CONVECTIVE DEVELOPMENT THIS AFTERNOON. ISOLATED TO SCATTERED CONVECTION WILL REMAIN POSSIBLE THROUGHOUT CENTRAL NC THIS AFTERNOON...GIVEN THE PRESENCE OF THESE TWO CONVERGENCE-FOCUSING BOUNDARIES AMIDST DEVELOPING WEAK TO MODERATE BOUNDARY LAYER (BL)-BASED INSTABILITY PER MODIFIED 12Z PROXIMITY RAOBS FOR REPRESENTATIVE BL PARCELS OF UPPER 70S-LOWER 80S TEMPERATURES OVER 50 TO 60 DEGREE DEWPOINTS...FROM NW TO SE. ALOFT...A PAIR OF VORTICITY MAXIMA STRETCHED FROM THE SC UPSTATE TO WEST-CENTRAL NC -- THE FORMER APPARENT ON SATELLITE IMAGERY AND MUCH STRONGER PER RUC MID LEVEL VORTICITY ANALYSES -- WILL DRIFT EASTWARD IN WEAK (10-15 KTS) WESTERLY MID LEVEL STEERING FLOW. THESE FEATURES MAY FOCUS CONVECTION FROM CENTRAL SC TO SE NC THIS AFTERNOON. STORMS HAVE ALSO ALREADY FIRED ON THE EAST-FACING SLOPES OF THE NC/VA BLUE RIDGE...AND THE CONVECTIVE ALLOWING MODELS (CAMS) CONTINUE TO INDICATE THE POTENTIAL FOR THESE TO PROPAGATE ON THEIR CONGLOMERATE OUTFLOWS -- AND WITH THE AFOREMENTIONED WEAK MID LEVEL STEERING FLOW -- EASTWARD INTO THE WESTERN PIEDMONT THROUGH EARLY THIS EVENING. SOME OF THIS ACTIVITY MAY CONTINUE EASTWARD ACROSS THE REMAINDER OF CENTRAL NC OVERNIGHT...THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO CARRY MORE THAN A SLIGHT TO LOW CHANCE POP INTO THE NIGHT TIME HOURS. MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC...WHICH HAS ALREADY SUPPORTED AN EXPANSIVE AREA OF MARINE STRATUS AND FOG ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...WILL PROMOTE THE DEVELOPMENT OF LOW STRATUS AND FOG FROM NE TO SW ACROSS THE CWFA BETWEEN 04-10Z. GIVEN A LACK OF APPRECIABLE CAA EXCEPT OVER THE FAR NORTHEAST...LOWS WILL BE SIMILAR TO PREVIOUS NIGHTS - 52 TO 58... COOLEST NORTHEAST. OVERNIGHT: BEHIND THE FRONT...COOLER AND MOIST MARITIME NORTHEASTERLY FLOW IS EXPECTED TO RESULT IN SLIGHTLY COOLER OVERNIGHT LOWS TONIGHT...ESPECIALLY ACROSS THE NORTHEAST. THEREFORE...AM EXPECTING MIN TEMPS TO RANGE FROM THE LOWER 50S ACROSS THE NORTHEAST TO MID/UPPER 50S FURTHER SOUTH AND WEST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 305 PM... RIDGE ALOFT OVER THE EASTERN UNITED STATES WITH SURFACE HIGH PRESSURE OFFSHORE. WEAK WINDS...PRECIPITABLE WATERS NEAR ONE INCH AND MINIMAL INSTABILITY AND POTENTIAL ENERGY SUGGESTS NO MORE THAN A ONE IN FIVE CHANCE FOR MEASURABLE RAIN... DIURNALLY DRIVEN BY AFTERNOON HEATING. LOW LEVEL THICKNESSES 25 TO 30 METERS ABOVE NORMAL WITH SOME MINIMAL REDUCTION IN INSOLATION BY CLOUDS DURING THE AFTERNOON. AFTERNOON HIGH TEMPERATURES 76 TO 81. LOW TEMPERATURES IN THE MID TO UPPER 50S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 305 PM... DEEP SLOWLY PROGRESSING TROUGH OR CUT OFF LOW OVER TEXAS WEDNESDAY MORNING ATTEMPTS TO REACH THE CAROLINAS LATE IN THE PERIOD... ALTHOUGH THE EAST COAST RIDGE RESISTS. MODEL SPREAD IN SOLUTIONS REDUCES CONFIDENCE... AS DOES LACK OF DECENT RUN TO RUN CONTINUITY WITHIN MODELS. MODELS FREQUENTLY TOO FAST WITH CUT OFF LOWS AND WILL FAVOR THE SLOWER GFS TIMING... THOUGH THIS MAY ALSO BE TOO FAST. WILL CONTINUE LOW CHANCES FOR MAINLY AFTERNOON SHOWERS OR A THUNDERSTORM FROM PREVIOUS DAYS INTO MID WEEK WITH RAIN CHANCES RISING TO 30 TO 40 PERCENT FOR FRIDAY AND SATURDAY AS WINDS ALOFT BEGIN TO INCREASE. AFTERNOON HIGH TEMPERATURES IN THE MID 70S. LOW TEMPERATURES MID AND UPPER 50S. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... AS OF 210 PM SATURDAY... VFR CONDITIONS...OUTSIDE OF SCATTERED SHOWERS AND STORMS MAINLY THROUGH THIS EVENING...WILL CONTINUE THROUGH EARLY TONIGHT. THESE CONDITIONS WILL THEN DETERIORATE TO IFR CEILINGS AND MVFR-IFR VISIBILITIES FROM NE TO SW BETWEEN 04-10Z...OWING TO MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC. INDEED...AN EXPANSIVE AREA OF MARINE STRATUS AND FOG HAD ADVECTED ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...AND THIS IS THE AIR MASS THAT WILL CONTINUE SOUTHWESTWARD AND CAUSE THE DETERIORATING AVIATION CONDITIONS ACROSS CENTRAL NC OVERNIGHT. CONDITIONS WILL GRADUALLY IMPROVE WITH HEATING ON SUNDAY...WITH VISIBILITIES BECOMING VFR AND CEILINGS LIFTING TO MVFR BETWEEN 13-16Z. LOOKING BEYOND 18Z SUNDAY: SCT TO BKN 2000-3500 FT CLOUDS WILL LINGER THROUGHOUT THE AFTERNOON SUN...AND ANY PARTIAL CLEARING LATE IN THE DAY AND DURING THE EVENING WILL CAUSES AREAS OF FOG AND/OR STRATUS TO REDEVELOP OVERNIGHT INTO EARLY MON. MORNING FOG OR STRATUS AND SCT TO BKN AFTERNOON CONVECTIVE CLOUD BASES GENERALLY BETWEEN 2500-3500 FT...AND ASSOCIATED ISOLATED TO WIDELY SCATTERED CONVECTION...WILL THEN RULE THROUGH THE MIDDLE OF THE WORK WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM... LONG TERM... AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK BACK DOOR COLD FRONT WILL SETTLE SOUTH THROUGH CENTRAL NC THROUGH TONIGHT. HIGH PRESSURE WILL FOLLOW AND RIDGE INTO NC FROM THE COASTAL MIDDLE ATLANTIC REGION THROUGH SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM SATURDAY... THROUGH EARLY TONIGHT: A SURFACE TROUGH/WEAK BACK DOOR COLD FRONT STRETCHED AT 18Z FROM NEAR KMRH-KSOP-KEXX...WHILE THE MORE NOTICEABLE COOLING RELATIVE TO TEMPERATURES OF FRI HAVE BEEN FOCUSED OVER NORTHEASTERN NC/SOUTHEASTERN VA OWING TO A MORE ONSHORE COMPONENT OF THE LOW LEVEL FLOW OFF OF COOL MIDDLE ATLANTIC COASTAL WATERS. THIS TRAILING MARITIME PUSH...ASSOCIATED ENHANCED CUMULUS FIELD PER VISIBLE SATELLITE IMAGERY...AND LOCATION OF A H85 TROUGH AXIS PER REGIONAL VWP DATA...WILL LIKELY MARK THE APPROXIMATE NORTHEASTWARD BOUND FOR THE POTENTIAL FOR DEEP CONVECTIVE DEVELOPMENT THIS AFTERNOON. ISOLATED TO SCATTERED CONVECTION WILL REMAIN POSSIBLE THROUGHOUT CENTRAL NC THIS AFTERNOON...GIVEN THE PRESENCE OF THESE TWO CONVERGENCE-FOCUSING BOUNDARIES AMIDST DEVELOPING WEAK TO MODERATE BOUNDARY LAYER (BL)-BASED INSTABILITY PER MODIFIED 12Z PROXIMITY RAOBS FOR REPRESENTATIVE BL PARCELS OF UPPER 70S-LOWER 80S TEMPERATURES OVER 50 TO 60 DEGREE DEWPOINTS...FROM NW TO SE. ALOFT...A PAIR OF VORTICITY MAXIMA STRETCHED FROM THE SC UPSTATE TO WEST-CENTRAL NC -- THE FORMER APPARENT ON SATELLITE IMAGERY AND MUCH STRONGER PER RUC MID LEVEL VORTICITY ANALYSES -- WILL DRIFT EASTWARD IN WEAK (10-15 KTS) WESTERLY MID LEVEL STEERING FLOW. THESE FEATURES MAY FOCUS CONVECTION FROM CENTRAL SC TO SE NC THIS AFTERNOON. STORMS HAVE ALSO ALREADY FIRED ON THE EAST-FACING SLOPES OF THE NC/VA BLUE RIDGE...AND THE CONVECTIVE ALLOWING MODELS (CAMS) CONTINUE TO INDICATE THE POTENTIAL FOR THESE TO PROPAGATE ON THEIR CONGLOMERATE OUTFLOWS -- AND WITH THE AFOREMENTIONED WEAK MID LEVEL STEERING FLOW -- EASTWARD INTO THE WESTERN PIEDMONT THROUGH EARLY THIS EVENING. SOME OF THIS ACTIVITY MAY CONTINUE EASTWARD ACROSS THE REMAINDER OF CENTRAL NC OVERNIGHT...THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO CARRY MORE THAN A SLIGHT TO LOW CHANCE POP INTO THE NIGHT TIME HOURS. MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC...WHICH HAS ALREADY SUPPORTED AN EXPANSIVE AREA OF MARINE STRATUS AND FOG ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...WILL PROMOTE THE DEVELOPMENT OF LOW STRATUS AND FOG FROM NE TO SW ACROSS THE CWFA BETWEEN 04-10Z. GIVEN A LACK OF APPRECIABLE CAA EXCEPT OVER THE FAR NORTHEAST...LOWS WILL BE SIMILAR TO PREVIOUS NIGHTS - 52 TO 58... COOLEST NORTHEAST. OVERNIGHT: BEHIND THE FRONT...COOLER AND MOIST MARITIME NORTHEASTERLY FLOW IS EXPECTED TO RESULT IN SLIGHTLY COOLER OVERNIGHT LOWS TONIGHT...ESPECIALLY ACROSS THE NORTHEAST. THEREFORE...AM EXPECTING MIN TEMPS TO RANGE FROM THE LOWER 50S ACROSS THE NORTHEAST TO MID/UPPER 50S FURTHER SOUTH AND WEST. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY... SUN: THE WEAK SURFACE FRONT WILL MOVE SOUTH TO NEAR THE NC/SC STATE LINE BY SUNDAY MORNING AS A STRONG (~1030MB) SURFACE HIGH CENTERED OFF THE MID ATLANTIC COAST RIDGES INTO THE AREA FROM THE NORTHEAST. AS STATED ABOVE...THE REGION WILL STILL REMAIN IN A FAVORABLE PATTERN ALOFT TO SEE SOME WEAK SHORTWAVE DISTURBANCES MOVING ATOP THE MID LEVEL RIDGE IN PLACE. WHILE PWAT VALUES WILL STILL BE HIGH (1.2-1.3 INCHES)...A SLIGHTLY MORE STABLE POST FRONTAL AIR MASS WILL BE IN PLACE...ESPECIALLY ACROSS THE NORTHEASTERN HALF OF THE FORECAST AREA. MODELS PROG WEAK INSTABILITY OF 500 TO 800 J/KG ACROSS THE SOUTHWESTERN HALF OF THE FORECAST AREA...CLOSER TO THE STALL FRONTAL BOUNDARY. WITH ALL THE ABOVE IN MIND...WILL TREND POPS FROM SLIGHT CHANCE ACROSS THE NORTHEAST TO CHANCE POPS FURTHER SOUTH AND WEST AND WILL ALSO INCLUDE A MENTION OF THUNDER ACROSS THE SOUTHWEST DUE TO THE PROXIMITY OF THE STALLED FRONTAL BOUNDARY. HIGHS ARE EXPECTED TO RANGE FROM THE LOW/MID 70S ACROSS THE NORTHEAST TO MID/UPPER 70S FURTHER SOUTH AND WEST. SUNDAY NIGHT THROUGH MONDAY NIGHT: SURFACE HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST IS FORECAST TO MOVE FURTHER OUT INTO THE ATLANTIC SUNDAY NIGHT AND INTO MONDAY AS STALLED FRONTAL ZONE SOUTH OF THE AREA CONTINUES TO WEAKEN/DISSIPATE. MID-LEVEL RIDGE AXIS CENTERED FROM THE GULF OF MEXICO NORTHWARD THROUGH THE GREAT LAKES REALLY BEGINS TO RESPOND TO THE UPSTREAM HIGH AMPLITUDE TROUGH BARRELING ONTO THE WEST COAST. MODELS INDICATE LOW-LEVEL THICKNESSES WILL TO BE THE HIGHEST ON MONDAY...WHICH WILL LIKELY SUPPORT THE WARMEST DAY OF THE WEEK WITH AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S...WITH SOME OF THE WARMEST READINGS ACROSS THE WESTERN PART OF THE STATE. THIS STRONG DAYTIME HEATING WILL FUEL WEAK DESTABILIZATION WITH THE RESERVOIR OF HIGH...1.1 TO 1.2" OF PWATS SUPPORTING ISOLATED/SLIGHT CHANCE DIURNAL CONVECTION...WITH THE POTENTIAL FOR HIGHER POPS ACROSS THE EAST WHERE MODELS DEPICT A LOW-LEVEL CONVERGENCE ZONE ALONG AN INVERTED COASTAL TROUGH LIKE FEATURE THAT COULD ENHANCE A SEABREEZE BOUNDARY. ADDITIONALLY...HIGHER POPS MAY ALSO BE NEEDED ON MONDAY IF SOME OF THE MODELS ARE CORRECT WITH SHOWING AN UPPER SHORTWAVE VORT DISTURBANCE DIVING SOUTH/SOUTHEAST ATOP THE RIDGE AXIS AND ACROSS THE AREA. CONFIDENCE WITH THIS FEATURE IS LOW AT THIS TIME AND WILL KEEP POPS AT SLIGHT CHANCE...EXCEPT A SMALL CHANCE ACROSS THE SOUTHEAST. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... ...UNSEASONABLY WARM TEMPERATURES WILL CONTINUE THROUGH THE UPCOMING WORK WEEK... THERE IS GOOD MODEL AGREEMENT AMONG THE VARIOUS DETERMINISTIC AND ENSEMBLE GUIDANCE THAT A CUT-OFF LOW WILL EVOLVE OVER THE SOUTHWEST DURING THE TUESDAY/WEDNESDAY TIMEFRAME...WITH A SLOW EAST/ NORTHEASTWARD PROGRESSION THROUGH THE REMAINDER OF THE PERIOD. GIVEN CUT-OFF STRUCTURE...WILL GIVE GREATER WEIGHT TO THE SLOWER MODEL SOLUTIONS WHICH DELAY ANY IMPACTS ON SENSIBLE WEATHER UNTIL LATE FRIDAY/SATURDAY. AS SUCH CENTRAL NC WILL CONTINUE TO SEE UNSEASONABLY WARM TEMPERATURES DOWNSTREAM OF THE SYSTEM IN THE ANOMALOUSLY HIGH HEIGHTS PARKED OVER THE EASTERN US. EXPECT HIGHS EACH DAY IN THE MID TO UPPER 70S WITH MILD NIGHTTIME LOWS IN THE MID 50S. ONSHORE LOW-LEVEL FLOW WILL SUPPORT ISOLATED AND MAINLY DIURNALLY DRIVEN CONVECTION TIED TO MESOSCALE INFLUENCES/FORCING SUCH AS LOCALLY ENHANCE CONVERGENCE ZONES ALONG THE SEABREEZE NEAR THE COAST...AND OUTFLOW BOUNDARIES ORIGINATING FROM CONVECTION FIRING ALONG THE HIGHER TERRAIN. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 210 PM SATURDAY... VFR CONDITIONS...OUTSIDE OF SCATTERED SHOWERS AND STORMS MAINLY THROUGH THIS EVENING...WILL CONTINUE THROUGH EARLY TONIGHT. THESE CONDITIONS WILL THEN DETERIORATE TO IFR CEILINGS AND MVFR-IFR VISIBILITIES FROM NE TO SW BETWEEN 04-10Z...OWING TO MOIST MARITIME NORTHEASTERLY FLOW FROM OFF THE ATLANTIC. INDEED...AN EXPANSIVE AREA OF MARINE STRATUS AND FOG HAD ADVECTED ALL THE WAY DOWN THE MID ATLANTIC COASTAL WATERS TO NEAR KORF AS OF 18Z...AND THIS IS THE AIR MASS THAT WILL CONTINUE SOUTHWESTWARD AND CAUSE THE DETERIORATING AVIATION CONDITIONS ACROSS CENTRAL NC OVERNIGHT. CONDITIONS WILL GRADUALLY IMPROVE WITH HEATING ON SUNDAY...WITH VISIBILITIES BECOMING VFR AND CEILINGS LIFTING TO MVFR BETWEEN 13-16Z. LOOKING BEYOND 18Z SUNDAY: SCT TO BKN 2000-3500 FT CLOUDS WILL LINGER THROUGHOUT THE AFTERNOON SUN...AND ANY PARTIAL CLEARING LATE IN THE DAY AND DURING THE EVENING WILL CAUSES AREAS OF FOG AND/OR STRATUS TO REDEVELOP OVERNIGHT INTO EARLY MON. MORNING FOG OR STRATUS AND SCT TO BKN AFTERNOON CONVECTIVE CLOUD BASES GENERALLY BETWEEN 2500-3500 FT...AND ASSOCIATED ISOLATED TO WIDELY SCATTERED CONVECTION...WILL THEN RULE THROUGH THE MIDDLE OF THE WORK WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...KRR/CBL LONG TERM...CBL AVIATION...MWS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
252 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK SURFACE TROUGH MEANDERING ACROSS THE REGION WILL BRING ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND AND INTO MONDAY. OTHERWISE...ABOVE NORMAL TEMPERATURES WILL PREVAIL THROUGH MUCH OF NEXT WEEK...AS AN UPPER RIDGE OVER THE REGION AMPLIFIES. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...EAST-WEST BOUNDARY SEPARATING NRLY AND SRLY WINDS VERY ROUGHLY BISECTING THE REGION RIGHT NOW/CLOSE TO THE STATE LINE. RUC ANALYSIS SUGGESTS THIS BOUNDARIES VERTICAL IDENTITY EXTENDS TO ABOUT 925MB OR 3KFT. HIGHER DEWPOINTS AND LOWER LCLS CONTINUE TO BE FOUND TO THE NORTH OF THIS BOUNDARY BUT ALAS CU FIELDS CONTINUE TO BE MINIMAL. RADAR PRESENTATION OF SEA BREEZE ALSO SUGGESTS A DEPTH OF ABOUT 3KFT. IN THE ABSENCE OF SYNOPTIC SCALE LIFT NEITHER OF THESE ARE GOING TO BE TERRIBLY EFFECTIVE IN LEADING TO CONVECTION WITH LFCS CURRENTLY CLOSER TO 6KFT. THIS SYNOPTIC ASCENT THOUGH GENTLE WILL BE PROVIDED BY THE SHORTWAVE CURRENTLY COMING OUT OF EASTERN TN. THERE IS STILL A SHORT WINDOW OF OPPORTUNITY FOR CONVECTION TODAY FROM ABOUT 20 OR 21 UTC THROUGH SUNDOWN AT WHICH TIME ANY COVERAGE OF STORMS WILL QUICKLY RUN OUT OF DIURNALLY DRIVEN INSTABILITY. AS SEEN LAST NIGHT HOWEVER IT IS DIFFICULT TO GO WITH A COMPLETELY DRY OVERNIGHT FORECAST IN LIGHT OF A TRAILING 10 S-1 VORT OR TWO STILL PROGGED TO MOVE ACROSS. THUS-20 POPS CARRIED OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...A WEAK E-W SURFACE BOUNDARY WILL MEANDER SOUTHWARD OVER OUR FORECAST ZONES ON SUNDAY. DESPITE REMAINING BENEATH AN UPPER RIDGE...ENOUGH COLUMN MOISTURE AND INSTABILITY WILL EXIST TO MAINTAIN ISOLATED SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY. IT SHOULD BE NOTED THE ENVIRONMENTAL WIND FIELD WILL REMAIN UNIMPRESSIVE AND ANY STORMS THAT FORM WILL FAVOR SURFACE HEATING AND WILL LIKELY EXHIBIT PULSE CHARACTERISTICS. BY MONDAY WE MAY SEE THE BOUNDARY LIFTING BACK NORTH. MOISTURE AND INSTABILITY REMAIN SIMILAR AND HAVE EXTENDED ISOLATED POP VALUES INTO MONDAY. GIVEN THE EXCESSIVE WARMTH...SEA-BREEZE CONVERGENCE MAY ALSO PLAY A ROLE INITIATING CONVECTION SUNDAY AND MONDAY IN THE AFTERNOON AND EARLY EVENINGS. MILD TEMPERATURES WILL PREVAIL BOTH DAYS BENEATH THE THERMAL RIDGE...JUST A FEW DEGREES COOLER ACROSS THE NORTHERN ZONES SUNDAY BEHIND THE FRONT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...DEEP 5H TROUGH OVER THE SOUTHWEST...A FAMILIAR SIGHT THIS YEAR...AT THE START OF THE PERIOD PROVIDES PLENTY OF UNCERTAINTY IN THE LONG RANGE PERIOD. MEDIUM RANGE GUIDANCE IN DECENT AGREEMENT ON THE TROUGH TURNING INTO A 5H CUTOFF...BUT LITTLE ELSE. TIMING REMAINS A BIG QUESTION AS SURFACE AND UPPER RIDGING ALONG THE EAST COAST IS SURE TO HOLD STRONGER THAN GUIDANCE INDICATES...MEANING THE MEDIUM RANGE SOLUTIONS ARE ALL LIKELY TOO FAST MOVING THE 5H TROUGH/CUTOFF LOW EAST. HPC IS ALSO FAVORING A SLOWER SOLUTION. THE END RESULT WILL BE A SUMMER-LIKE PATTERN WITH STRENGTHENING 5H RIDGE AND BERMUDA HIGH. DIURNAL/SEA BREEZE CONVECTION MAY DEVELOP TUE/WED BUT BUILDING 5H RIDGE AS THE UPPER TROUGH/LOW MOVES EAST WILL HELP SUPPRESS UPWARD MOTION THU AND MAYBE FRI DEPENDING ON HOW SLOW THE TROUGH/LOW MOVES EAST. COLD FRONT MOVING INTO THE REGION LATE IN THE PERIOD WILL PROVIDE THE BEST CHANCES FOR WIDESPREAD PRECIP. AREA OF DEEP MOISTURE AHEAD OF THE FRONT IS LIMITED AND IT LOOKS LIKE THE BEST DYNAMICS PASS TO THE NORTH. GIVEN THE UNCERTAINTY AND THE MARGINAL CONDITIONS DO NOT FEEL ANYTHING MORE THAN A LOW CHANCE POP IS WARRANTED. TEMPERATURES WILL RUN ABOVE TO WELL ABOVE CLIMO WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE MID 50S. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 19Z...TERMINALS ARE VFR THIS AFTERNOON. SKIES ARE GENERALLY SCATTERED...AND CUMULUS HAS JUST BEGUN TO DEVELOP. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH TODAY. A PIEDMONT TROUGH WILL EXIST FROM KLBT TO KFLO AND A SEA BREEZE WILL DEVELOP AND MOVE SLIGHTLY INLAND OF THE COASTAL TERMINALS LATER THIS AFTERNOON. SUFFICIENT INSTABILITY WILL EXIST NEAR THESE FOCUS AREAS FOR ISOLATED TO WIDELY SCATTERED SHOWERS TO OCCUR THROUGH MUCH OF THIS TAF VALID PERIOD. ISOLATED THUNDERSTORMS WILL ALSO DEVELOP ONCE THE CONVECTIVE TEMPERATURE IS REACHED OVER THE NEXT SEVERAL HOURS. CONFIDENCE IS HIGHEST THAT THUNDERSTORMS WILL OCCUR NEAR THE KILM AND KLBT TERMINALS LATER THIS AFTERNOON WITH TEMPO MVFR/IFR POSSIBLE. OTHERWISE...MAINLY SHOWERS CAN BE EXPECTED. VFR CAN BE EXPECTED OUTSIDE OF SHOWERS AND THUNDERSTORMS. DUE TO THE PROXIMITY OF THE FRONT PRECIPITATION SHOULD LINGER THROUGH MUCH OF THE EVENING AND OVERNIGHT HOURS. WINDS WILL BE SOUTHWEST TODAY 5-10 KNOTS...BECOMING SOUTH AT THE COASTAL TERMINALS IN THE NEXT SEVERAL HOURS DUE TO THE SEA BREEZE. THIS EVENING AND OVERNIGHT WINDS WILL LIKELY BECOME LIGHT SOUTHWEST AT THE SOUTHERN TERMINALS AND LIGHT AND VARIABLE AT KILM AND KLBT. AT KILM AND KLBT THERE IS A GOOD CHANCE FOR IFR STRATUS TO DEVELOP... WHILE MVFR VISIBILITIES WILL BE MOST LIKELY AT THE REMAINING TERMINALS. EXPECT MVFR CONDITIONS OR GREATER 14-16Z WITH SHOWERS DEVELOPING. EXTENDED OUTLOOK...THROUGH THE PERIOD...MORNING FOG/MVFR...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE AFTERNOON...THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...WINDSHIFT BOUNDARY WILL BE LURKING NOT TOO FAR TO THE NORTH OF THE AREA FOR MOST OF THE PERIOD. THIS BOUNDARY HAS MADE MORE SOUTHERN PROGRESS OVER LAND THAN OVER WATER AND THIS WILL LIKELY HOLD TRUE OVERNIGHT. THIS WILL PRECLUDE ANY NORTHERLY WIND COMPONENT FROM ENTERING THE FORECAST AREA ALTHOUGH NORTHERN ZONES MAY GO VERY LIGHT AND VARIABLE AS A RESULT OF HE PROXIMITY OF THE TROUGH. LIGHT S TO SWRLY FLOW CAPPED AT 10 KTS WILL REMAIN IN PLACE ELSEWHERE AS WEAK BERMUDA HIGH PRESSURE CONTINUES TO BE THE DOMINANT WIND MAKER. SEAS REMAINING RELATIVELY DIMINUTIVE AT 2 TO 3 FT. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...BY DAYBREAK SUNDAY NE WINDS WILL PREVAIL N OF CAPE FEAR AS AN E-W FRONTAL BOUNDARY SLIPS SLOWLY SOUTHWARD. WIND SPEEDS WILL HOLD BELOW 20-25 KNOTS SO ADVISORIES WILL NOT BE NEEDED. THE FRONT MAY NOT MAKE IT TO WINYAH BAY LATE SUNDAY AND COULD MOVE BACK NORTH SUNDAY NIGHT INTO MONDAY. THUS WE MAY VERY WELL SEE A VARIABLE WIND DIRECTION SUNDAY AND MONDAY WITH LIGHT SPEEDS OVERALL. NO PROBLEMS WITH SEAS...ESSENTIALLY 2-3 FT IN A MIX OF SE WAVES AND SHORTER PERIOD SSW WIND CHOP. THE WEAK FRONTAL BOUNDARY MAY TRIP OFF ISOLATED TSTMS NEAR OR OVER THE WATERS. MARINERS SHOULD CONSULT RADAR TRENDS BEFORE HEADING OUT SUNDAY AND MONDAY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...MAJORITY OF THE PERIOD WILL BE MARKED BY SOUTH TO SOUTHEAST WINDS AT OR BELOW 10 KT. BERMUDA HIGH WILL BE THE MAIN FEATURE THOUGH LATE IN THE PERIOD A COLD FRONT WILL APPROACH FROM THE WEST. TIMING OF THE COLD FRONT REMAINS A BIG QUESTION...BUT EVEN THE FASTEST SOLUTION KEEPS THE FRONT TO THE WEST THROUGH THU EVENING. THE FASTER SOLUTION DOES LEAD TO A PINCHED GRADIENT THU WHICH WOULD PUSH SOUTHERLY FLOW CLOSE TO 20 KT. HOWEVER THE SLOWEST AND THE FASTEST SOLUTION IS FAVORED. SO WHILE THERE MAY BE A MARGINAL INCREASE IN SPEEDS THU AS GRADIENT TIGHTENS A LITTLE SPEEDS SHOULD REMAIN UNDER 15 KT. SEAS WILL RUN 2 TO 3 FT TUE INTO WED BUT A BUILDING EAST TO SOUTHEAST SWELL LATE IN THE PERIOD WILL PUSH SEAS INTO THE 3 TO 5 FT RANGE THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...MBB SHORT TERM...MJC LONG TERM...III AVIATION...MRR/MBB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1230 PM EDT SAT MAR 17 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DRIFT SOUTH OVER THE CAROLINAS INTO EARLY SUNDAY...BRINGING A FEW SHOWERS AND THUNDERSTORMS. WARM AND GENERALLY DRY CONDITIONS ARE EXPECTED MUCH OF NEXT WEEK...AS AN UPPER RIDGE AMPLIFIES OVER THE REGION. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM SATURDAY...A BOUNDARY LIES NEARLY STALLED ALONG NORTHERNMOST ZONES. INTERESTINGLY, SOME HIGHER DEWPOINTS HAVE POOLED NORTH OF THIS WINDSHIFT LINE. RUC ANALYSIS IS THUS SHOWING SOME INSTABILITY AND LOWER LCLS DEVELOPING IN THESE AREAS WHICH EXTEND INTO BLADEN AND ROBESON AND PARTS OF PENDER CTYS. THIS MAY END UP BEING WHERE CONVECTION INITIATES FIRST ALTHOUGH LATER INDICATION BY DEVELOPMENT OF CU FIELDS WILL ADD GREATER CONFIDENCE. 12Z GFS AND WRF BOTH SEEM TO SUPPORT THIS IDEA. OF LESSER CERTAINTY IS THE MODEL DEPICTION OF ANOTHER BOUNDARY DEVELOPING ROUGHLY PARALLEL TO THE SEA BREEZE...IF NOT THE ACTUAL SEABREEZE...ACROSS SC ZONES. (IT LOOKS A LITTLE TOO FAR INLAND TO BE THE ACTUAL SEABREEZE WHICH IS NOT EXPECTED TO MOVE FAR OR FAST INLAND TODAY). TIMING IS GOING TO BE A LITTLE LATER THAN PREV THOUGHT SO FCST HAS BEEN ADJUSTED ACCORDINGLY. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... AS OF 3:00 AM SATURDAY...MID LEVEL HEIGHTS WILL BUILD THROUGH THE PERIOD ALTHOUGH WITH THE DEVELOPING HIGH AMPLITUDE PATTERN THE AREA REMAINS ON THE EASTERN SIDE OF THE MAIN RIDGE AXIS. AT THE SURFACE A DECAYING FRONT ALONG WITH ANY NUMBER OF WEAK EMBEDDED SHORTWAVES OR CONVECTIVE VORTICIES WILL BE THE CATALYST FOR CONVECTION SUNDAY. THE MET GUIDANCE REMAINS MUCH HIGHER WHEN COMPARED TO THE GFS MAV NUMBERS BUT WITH A SUMMER LIKE PATTERN THESE NUMBERS CAN BE OF LIMITED UTILITY WITH SUCH WEAK FORCING. I HAVE MAINTAINED THE LOW CHANCE POPS FOR SUNDAY CITING THE FORMER. CANNOT RULE OUT SEA BREEZE ACTIVITY ALONG WITH THE RESIDUAL BOUNDARIES AND SUBTLE SHORTWAVES FOR ACTIVITY MONDAY ALTHOUGH I DID INCREMENTALLY DECREASE POPS AS THE FRONT WILL BE ALL BUT DISSIPATED. TEMPERATURE GUIDANCE HAS WARMED SLIGHTLY FOR SUNDAY AND REMAINS SIMILAR FOR THE REMAINDER OF THE PERIOD. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3:00 AM SATURDAY...FORECAST CHALLENGES WITH REGARDS TO THE EXTENDED CONTINUE TO BE FOCUSED IN THE WESTERN AND CENTRAL U.S. WITH THE TIMING OF THE MASSIVE TROUGH AND EVENTUAL CUTOFF AND ITS SLOW MOVEMENT. FOR OUR AREA...I HAVE MAINTAINED THE MAINLY DIURNAL CONVECTION WITH THE SUMMER LIKE PATTERN AND BERMUDA HIGH PRESSURE. POPS DO DECREASE INCREMENTALLY LATE AS THE RIDGE INTENSIFIES AS THE TROUGH PROGRESSES EAST. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 18Z...TERMINALS ARE VFR THIS AFTERNOON. SKIES ARE GENERALLY SCATTERED...AND CUMULUS HAS JUST BEGUN TO DEVELOP. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH TODAY. A PIEDMONT TROUGH WILL EXIST FROM KLBT TO KFLO AND A SEA BREEZE WILL DEVELOP AND MOVE SLIGHTLY INLAND OF THE COASTAL TERMINALS LATER THIS AFTERNOON. SUFFICIENT INSTABILITY WILL EXIST NEAR THESE FOCUS AREAS FOR ISOLATED TO WIDELY SCATTERED SHOWERS TO OCCUR THROUGH MUCH OF THIS TAF VALID PERIOD. ISOLATED THUNDERSTORMS WILL ALSO DEVELOP ONCE THE CONVECTIVE TEMPERATURE IS REACHED OVER THE NEXT SEVERAL HOURS. CONFIDENCE IS HIGHEST THAT THUNDERSTORMS WILL OCCUR NEAR THE KILM AND KLBT TERMINALS LATER THIS AFTERNOON WITH TEMPO MVFR/IFR POSSIBLE. OTHERWISE...MAINLY SHOWERS CAN BE EXPECTED. VFR CAN BE EXPECTED OUTSIDE OF SHOWERS AND THUNDERSTORMS. DUE TO THE PROXIMITY OF THE FRONT PRECIPITATION SHOULD LINGER THROUGH MUCH OF THE EVENING AND OVERNIGHT HOURS. WINDS WILL BE SOUTHWEST TODAY 5-10 KNOTS...BECOMING SOUTH AT THE COASTAL TERMINALS IN THE NEXT SEVERAL HOURS DUE TO THE SEA BREEZE. THIS EVENING AND OVERNIGHT WINDS WILL LIKELY BECOME LIGHT SOUTHWEST AT THE SOUTHERN TERMINALS AND LIGHT AND VARIABLE AT KILM AND KLBT. AT KILM AND KLBT THERE IS A GOOD CHANCE FOR IFR STRATUS TO DEVELOP... WHILE MVFR VISIBILITIES WILL BE MOST LIKELY AT THE REMAINING TERMINALS. EXPECT MVFR CONDITIONS OR GREATER 14-16Z WITH SHOWERS DEVELOPING. EXTENDED OUTLOOK...THROUGH THE PERIOD...MORNING FOG/MVFR...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE AFTERNOON...THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 10 AM...LIGHT BERMUDA HIGH-INDUCED SWRLY WINDS TO AVERAGE ABOUT 10 KT TODAY. SEAS RUNNING 2 TO 3 FT. DOMINANT PERIOD AT BOTH 41013 AND 41036 AROUND 9 SECONDS WITH A LESSER SPIKE SHOWING UP IN SPECTRAL GRAPHS AT A 4 SEC WIND CHOP. THESE CONDITIONS WILL PERSIST THROUGH THE PERIOD. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3:00 AM SATURDAY...VERY LIGHT PRESSURE PATTERN WILL PREVAIL WITH A FRONT BISECTING THE WATERS FROM EAST TO WEST INITIALLY. WEAK NORTHEASTERLY FLOW DEVELOPS FOR A SHORT TIME MONDAY BUT WILL GIVE WAY TO A EASTERLY FLOW LATE VIA THE SEABREEZE AND MORE-SO THE SYNOPTIC FLOW. GENERALLY SPEAKING WIND SPEEDS WILL BE TEN KNOTS OR LESS. THE LATEST SWAN RUN SHOWS 2-3 FOOT SEAS WHICH SEEM MORE THAN REASONABLE CONSIDERING THE TEPID WIND FIELDS. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3:00 AM SATURDAY...WITH A SUMMERTIME PATTERN IN PLACE...BERMUDA HIGH PRESSURE...EXPECT SOUTH TO SOUTHEAST WINDS THROUGH THE PERIOD. SEABREEZE CIRCULATION MAY BE ENHANCED BY THE STILL RELATIVELY COOLER WATER TEMPERATURES. CAVEAT TO THIS FORECAST IS THE MID LEVEL LOW THE GFS IS ADVERTISING AND IF A WEAK SURFACE LOW DEVELOPS. HAVE DISREGARDED THIS SOLUTION AS OF NOW AS IT APPEARS TO BE CONVECTIVELY INDUCED. SEAS WILL SLOWLY INCREASE AS THE FETCH PERSISTS FROM 2-3 FEET TO 2-4 FEET. A FEW FIVE FOOTERS CANNOT BE RULED OUT. WAVE SPECTRUM WILL PRIMARILY CONSIST OF LOCAL WIND GENERATED WAVES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...MBB SHORT TERM...SHK LONG TERM...SHK AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
310 PM CDT SAT MAR 17 2012 .NEAR TERM... LOW LEVEL MOISTURE CONTINUES TO SURGE NORTHWARD INTO THE AREA... AHEAD OF A DEEPENING LOW PRESSURE CENTER BACK IN EASTERN MT. A QUASI-STATIONARY BOUNDARY EXTENDED SOUTHERN MANITOBA AND WESTERN ONTARIO...JUST NORTH OF THE FGF FORECAST AREA. AT 2PM...DWPTS OF 50F OR GREATER EXTENDED FROM ABERDEEN...THROUGH COOPERSTOWN...TO THIEF RIVER FALLS AND ROSEAU. SOME +60F DEWPOINT AIR WAS EDGING TOWARDS THE EXTREME SOUTHEASTERN ND AND WEST CENTRAL MN. WITH MODERATE SOUTHERLY LOW LEVEL AND BOTH ADVECTING WARMTH AND MOISTURE...MOST AREAS WILL SEE MOTTLED SUNSHINE AND NEAR RECORD TEMPERATURES THROUGH THE AFTERNOON AND EARLY EVENING. NEAR SURFACE AIRMASS IS BECOMING INCREASING UNSTABLE ACROSS MUCH OF WEST CENTRAL AND NORTHWEST MN ATTM. RUC SHOWS HIGHEST ELEVATED INSTABILITY MOVING INTO NORTHWEST AND NCNTRL MN THROUGH THE LATE AFTERNOON AND EARLY EVENING. HAVE KEEP SLIGHT CHC OF TSTMS OVER NCNTRL MN AS PER PREVIOUS PACKAGE FOR THE EVENING HOURS. .SHORT TERM... TONIGHT THROUGH TUESDAY. INCREASING H850 WINDS AND MOISTURE ADVECTION OVERNIGHT WILL HELP TO SATURATE THE NEAR SFC AIRMASS AND TO DEVELOP PATCHY FOG AND MIST CONDITIONS FROM THE OVERNIGHT INTO EARLY MORNING PERIOD...BEGINNING ACROSS THE SOUTHERN RED RIVER BASIN AND ADVECTING NORTHWARD. ON SUNDAY...PATCHY FOG AND MIST SHOULD PERSIST INTO MID MORNING... WITH BREAKS APPEARING IN THE CLOUDS THROUGH THE FORENOON ALLOWING FOR SOME ADDITIONAL WARMING BY MIDDAY. ABUNDANT SUNSHINE AND INCREASING INSTABILITY THROUGH THE AFTERNOON COULD GIVE RISE TO SCATTERED SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO BY EARLY EVENING...WITH BOUNDARY FORCING STRONGEST NEARER THE CANAM BORDER. MONDAY...MOST OF THE AREA SHOULD SEE SOME RAINSHOWER ACTIVITY WITH EMBEDDED THUNDERSTORMS A STRONG POSSIBILITY. LOW PRESSURE IS EXPECTED TO DEEPEN INTO THE WESTERN DAKOTAS BY MONDAY MORNING WITH ALL OF EASTERN ND AND WESTERN MN IN AN AREA OF INCREASED LOW LEVEL MOISTURE AHEAD OF AN APPROACHING COLD FRONTAL BOUNDARY. THUNDERSTORMS ARE MOST LIKELY ON MONDAY AFTERNOON ALONG THE RED RIVER VALLEY AND POINTS EASTWARD INTO NORTHERN MINNESOTA TROUGH THE EVENING HOURS. SOUTH WINDS SHOULD BE QUITE GUSTY ON MONDAY AS WELL WITH TEMPERATURES ONCE AGAIN REACHING INTO RECORD SETTING VALUES. TUESDAY...DEEP CONVECTION SHOULD HAVE MOVED INTO CENTRAL AND NORTHCENTRAL MN BY TUESDAY MORNING...BUT MODEL GUIDANCE IS STILL INDECISIVE ON WHETHER THE SFC FRONT WILL PUSH THROUGH THE RED RIVER VALLEY BY THEN OR LINGER THROUGH THE DAY. FOR NOW...HAVE STUCK CLOSER TO THE SLOWER GFS SOLUTION...AND EXPECT SOME CONVECTION TO REDEVELOP ALONG AND EAST OF THE RED RIVER VALLEY INTO MIDDAY TUESDAY BEFORE FRONTAL PASSAGE PUSHES ALL RAIN INTO EASTERN MINNESOTA FOR THE LATE AFTERNOON AND EVENING PERIODS. OVERALL... TEMPERATURES SHOULD BE MUCH COOLER WITH WIDESPREAD CLOUD COVER EARLY... AND WINDS TURNING FROM WEST TO NORTHWEST LATE. .LONG TERM... WEDNESDAY THROUGH FRIDAY. A MILD AND GENERALLY DRY EXTENDED FORECAST PERIOD IS EXPECTED FOR THE EQUINOX WEEK OF MARCH AS THE MAIN JET STREAM CONTINUES TO REMAIN NORTH OF THE INTERNATIONAL BORDER. LOW LEVEL MOISTURE RETURN TO THE NORTHERN PLAINS WILL BE SCANT DUE TO CUTOFF LOW IN THE SOUTHERN MISSISSIPPI RIVER VALLEY. DUE TO NO SNOW COVER PRESENT...DAILY HIGH TEMPERATURES SHOULD STILL AVERAGE AT LEAST 15 DEGREES WARMER THAN SEASONAL NORMALS FOR LATE MARCH. THE SURFACE STORM TRACK SHOULD REMAIN NORTH OF THE INTERNATIONAL BORDER INTO NEXT WEEKEND. && .AVIATION... LOW LEVEL MOISTURE ADVECTING NORTHWARD OVERNIGHT SHOULD ALLOW MVFR CEILINGS TO CONTINUE TO MOVE NORTHWARD THIS EVENING. IN ADDITION...SOUNDINGS HINT AT POSSIBILITY OF -DZ AND BR DEVELOPMENT THIS EVENING...ESPECIALLY IN THE EAST AND SOUTH. THIS AREA WILL HAVE THE DEEPER MOISTURE PRESENT WITH THE RETURN FLOW. THUS...HAVE DECREASED VISIBILITIES AT KBJI AND ADDED -DZ AFTER SUNSET. KFAR WILL ALSO HAVE TO BE MONITORED AS WELL FOR POSSIBLE FOG AND DRIZZLE DEVELOPMENT. SOUTHEASTERLY SURFACE WINDS WILL INCREASE SUNDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS UP. AT THE PRESENT TIME...EXPECT SUSTAINED WINDS OF 15 TO 20 KNOTS WITH GUSTS AROUND 25 KNOTS TO BE PREVALENT THROUGH THE MORNING HOURS ON SUNDAY. && .HYDROLOGY... RIVER FLOOD WARNING FOR FARGO AT THE RED RIVER CONTINUES. THE RED RIVER CONTINUES TO RISE SLOWLY AND IS STILL FORECAST TO REACH A FOOT ABOVE FLOOD STAGE EARLY NEXT WEEK. OTHER POINTS DOWNSTREAM OF FARGO ALONG THE RED ARE SEEING WITHIN THE BANK RISES. SOME OF THE TRIBUTARIES OVER NE ND/NW MN WILL ALSO SEE WITHIN THE BANK RISES. THE CURRENT FCST OF RAINFALL FROM THE UPCOMING SYSTEM SHOULD NOT BE ENOUGH TO ALTER RIVER FORECASTS GREATLY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GUST/BRAMER/SPEICHER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1004 PM EDT SUN MAR 18 2012 .SYNOPSIS... AN UPPER LEVEL LOW WILL MOVE ACROSS THE AREA THIS EVENING. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE AREA THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE SIGNIFICANT RAINFALL HAS ENDED TO CANCELLED THE FLOOD WARNING EVEN THOUGH A FEW COUNTIES MAY STILL HAVE SOME MINOR FLOODING GOING ON. OTHERWISE SOME DECREASE IN CLOUDS OVER NORTHWEST OHIO AND SOME PATCHY DENSE FOG MAY DEVELOP. THE HRRR MODEL THINKS SOME SHOWERS COULD DEVELOP IN THIS AREA...KEPT IT DRY. OTHERWISE THE SHOWERS AND ISOLATED THUNDERSTORMS OVER EXTREME EASTERN OHIO AND NORTHWEST PA WILL SLOWLY MOVE EAST. ADJUSTED SOME OF THE LOWS DOWN BASED ON 9 PM READINGS. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/... WELL ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH MID WEEK AS RIDGE BUILDS OVER THE AREA AND WILL BE THE DOMINANT FEATURE. CONDITIONS SHOULD BE PREDOMINATELY DRY THROUGH MID WEEK. DID MENTION CHC TSRA MONDAY AFTERNOON AS CAPES BUILD TO BETWEEN 1000 J/KG AND 1500. HOWEVER...LACK OF ANY KICKER COULD HINDER DEVELOPMENT OF AFTERNOON TSRA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A COOLER TREND FOR THE END OF THE WEEK WITH AN UPPER LOW MOVING INTO THE OHIO VALLEY AND A COLD FRONT COMING ACROSS THE GREAT LAKES. TIMING STILL IS AN ISSUE AND LIKELY THIS WILL TAKE A COUPLE/FEW DAYS TO CROSS THE REGION. MODEL DIFFERENCES ON PHASING BETWEEN NORTHERN SHORTWAVE AND THE MID U.S. UPPER LOW. EVEN MORE DIFFERENCE UPON TIMING OF ITS EXIT AND THE ARRIVAL OF HIGH PRESSURE...WITH THE ECMWF STILL THE FASTEST AND ALSO A LITTLE COOLER. TEMPERATURES WILL REMAIN ABOVE NORMAL...WILL JUST BE ABOUT 15 OR SO DEGREES COOLER FOR HIGHS THIS WEEKEND. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... AS AIRMASS COOLS TONIGHT SHOULD SEE MOST OF THE CONVECTION WEAKEN SO BY LATE EVENING SHOULD BE MOSTLY JUST SCT SHRA WHICH WILL SHIFT INTO MOSTLY THE EAST PART OF THE AREA FOR THE SECOND HALF OF THE NIGHT. AS THE CLOUDINESS DISSIPATES AND TEMPS COOL...FOG SHOULD START TO FORM. WILL CONTINUE WITH PREVIOUS FORECAST AND TAKE MANY OF THE TAFS DOWN TO IFR FOR VSBY AND LOW CIGS. THE FOG AND LOW CLOUDS WILL BREAK UP BY LATE MON MORNING THEN SCT TO BKN CU WILL DEVELOP BY MIDDAY. THE AIRMASS WILL BECOME UNSTABLE ENOUGH FOR ISOLD TO SCT SHRA/TSRA TO DEVELOP BUT COVERAGE NOT HIGH ENOUGH TO MENTION IN TAFS YET. OUTLOOK...NON VFR POSSIBLE IN MORNING BR TUESDAY AND WEDNESDAY. NON VFR POSSIBLE THURSDAY INTO FRIDAY. && .MARINE... OUTSIDE OF ISOLATED/SCATTERED THUNDERSTORMS...LAKE CONDITIONS QUIET. LIGHT FLOW WILL CONTINUE THROUGH THE WEEK AND FOR THE MOST PART WINDS WILL BE SOUTHERLY. THERE IS A FRONT THAT WILL MOVING ACROSS THE CENTRAL LAKES MID WEEK AND MAY WANT TO SLIP ACROSS LAKE ERIE THURSDAY...BUT TIMING OF FEATURES LATE THIS WEEK COMPLICATED BY A CUT OFF LOW THAT WILL BE MAKING ITS WAY SLOWLY TO THE OHIO VALLEY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...DJB NEAR TERM...KIELTYKA SHORT TERM...DJB LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
643 PM EDT SAT MAR 17 2012 .SYNOPSIS... WITH HIGH PRESSURE ANCHORED OFF THE EAST COAST...A SOUTHERLY FLOW AROUND THE HIGH WILL ALLOW AN UNSEASONABLY WARM AIRMASS TO PERSIST THROUGH MUCH OF THE UPCOMING WEEK. A MID LEVEL DISTURBANCE INTERACTING WITH THE UNSTABLE AIRMASS WILL PRODUCE THUNDERSTORMS MAINLY LATE TONIGHT INTO SUNDAY. THE FLOW OVER THE OHIO VALLEY WILL BECOME ANTICYCLONIC AND WARMER AIR WILL MOVE IN ALOFT ON MONDAY WHICH WILL BRING AN END TO THE THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... ISOLATED SHOWERS ARE OCCURRING WITH INSTABILITY INCREASING SLIGHTLY DUE TO DAYTIME HEATING. AFTER A LULL AROUND SUNSET...ACTIVITY WILL INCREASE IN COVERAGE AND INTENSITY LATER TONIGHT WHEN THE ATMOSPHERE DESTABILIZES DUE TO COOLING ALOFT ASSOCIATED WITH A SHORT WAVE MOVING UP FROM THE SOUTHWEST. KEPT LIKELY POPS WITH HIGHEST VALUES NEAR THE OHIO RIVER. TEMPERATURES WILL FALL TO THE UPPER 50S FOR LOWS...ABOVE NORMAL HIGHS IN THE LOWER 50S FOR THIS PERIOD. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... THUNDERSTORMS WILL LIKELY PERSIST ON SUNDAY AS THE SHORT WAVE CRAWLS NORTH AND INSTABILITY LINGERS INTO THE AFTERNOON. WIDESPREAD SEVERE THUNDERSTORMS ARE NOT EXPECTED DUE TO MARGINAL INSTABILITY AND RATHER WEAK WIND FIELDS...THOUGH CANNOT RULE OUT LARGE HAIL WITH WBZ HEIGHTS AROUND 9 KFT. THUNDERSTORMS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS THE SHORT WAVE LIFTS NORTH AND AN UPPER RIDGE STARTS TO BUILD IN. DRY WEATHER IS EXPECTED BY MONDAY EVENING AS THE UPPER RIDGE BECOMES ESTABLISHED AND A CYCLONIC FLOW DEVELOPS IN LOWER LEVELS. TEMPERATURES WILL STAY MORE THAN 20 DEGREES ABOVE NORMAL THROUGH THE PERIOD. HIGHS IN THE MID AND UPPER 70S ON SUNDAY AND AROUND 80 ON MONDAY WILL BE FLIRTING WITH RECORD HIGHS AT OUR 3 CLIMATE SITES AT CINCINNATI...COLUMBUS AND DAYTON. && .LONG TERM /TUESDAY THROUGH SATURDAY/... HIGHLY AMPLIFIED MID/UPPER LEVEL FLOW PATTERN WITH A TROF OVER THE WEST AND A LARGE RIDGE OVER THE EASTERN UNITED STATES. THIS RIDGE WILL PROVIDE DRY WEATHER AND MUCH ABOVE NORMAL TEMPERATURES. FOR TUESDAY HAVE FCST HIGHS FROM NEAR 80 NORTH TO THE LOWER 80S SOUTH. RECORD HIGHS WILL BE IN JEOPARDY OF FALLING. TUESDAYS RECORD HIGHS ARE CVG 82, DAY 79 AND CMH 78. THE STRONG UPPER LEVEL RIDGE TO SLIDE OFF TO THE EAST COAST ON WEDNESDAY WITH THE UPPER TROF MOVING INTO THE NATIONS MID SECTION. GIVEN THE HIGH DEGREE OF AMPLIFICATION...PREFER THE SLOWER ECMWF SOLN...KEEPING THE REGION DRY ON WED. EXPECT HIGHS TO RANGE FROM THE UPPER 70S NORTH TO 80 SOUTH. AGAIN RECORDS WILL BE IN JEOPARDY WITH WEDNESDAY RECORDS STANDING AT 79 FOR CVG, 78 FOR DAY AND 80 AT CMH. UPPER LEVEL LOW TO PUSH SLOWLY EAST INTO THE OHIO VALLEY THURSDAY/FRIDAY. NUMERICAL MODELS GENERALLY SIMILAR WITH THE CENTER OF THE LOW CLOSE TO CVG BY FRIDAY EVENING. WILL INTRODUCE LOW POPS INTO THE SW LATE WED NIGHT AND THEN SPREAD THIS CHC NE ACRS THE FA THURSDAY. WL BUMP POPS UP TO HIGH CHC LATE THURSDAY NIGHT/EARLY FRIDAY WITH THE APPROACH OF SFC FRONTAL BOUNDARY. UNDER CONTD INFLUENCE OF THE UPPER LOW...WL CONTINUE LOW POPS INTO NEXT WEEKEND. HAVE TRENDED THURSDAYS AND FRIDAYS HIGHS A LTL ABOVE GUID BUT OPTED TO GO COOLER ON SATURDAY FOLLOWING ECMWF SOLN WHICH BRINGS IN COLDER AIR. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... REGION CONTINUES TO BE LOCATED ON THE BACK SIDE OF A MID LVL RIDGE AXIS WHICH STRETCHES FROM THE GULF COAST NE INTO NEW ENGLAND. WEATHER PATTERN IS COMPARABLE TO A LATE SPRING OR EARLY SUMMER REGIME WITH EMBEDDED DISTURBANCES MOVING NE ON THE BACK SIDE OF THE RIDGE AXIS AND CONSEQUENTLY TRIGGERING AREAS OF SHOWERS AND STORMS IN THE MOIST...UNSTABLE AIR. MODELS USUALLY HAVE A HARD TIME ON PLACEMENT...TIMING AND COVERAGE OF STORMS AND TONIGHT INTO SUNDAY WILL BE NO DIFFERENT. HAVE OPTED TO TRY AND PINPOINT THE VERY SHORT TERM AND BROAD BRUSH THE LONG TERM BEYOND 6 HOURS GIVEN LOW CONFIDENCE. WITH THAT SAID...MOSAIC RADAR WAS SHOWING A BROKEN LINE OF SHOWERS AND THUNDERSTORMS STRETCHING FROM SRN INDIANA INTO NORTHERN KENTUCKY NEAR KSDF. HRRR MODEL AND RADAR MOVEMENT SUGGEST THAT THIS ACTIVITY SHOULD MAKE IT NEAR KCVG AND KLUK BETWEEN 02Z AND 03Z AS LONG AS IT DOES NOT FALL APART. HAVE PLACED A VCTS AND CB IN KCVG AND KLUK IN REGARDS TO THIS POTENTIAL ACTIVITY. FOR THE REMAINDER OF THE NIGHT...ALL EYES FOCUS ON A MAIN DISTURBANCE LOCATED TO THE WEST OVER MISSOURI/ILLINOIS. THIS FEATURE IS FORECAST TO SLOWLY ROTATE ENE THROUGH THE AREA ON SUNDAY. POTENTIAL EXITS FOR SHOWERS WITH EMBEDDED THUNDER AS IT MOVES THROUGH. FOR NOW...HAVE PLACED VFR SHOWERS IN THE TAFS IN CONJUNCTION WITH THE BEST FORCING...KNOWING THAT LOCAL MVFR OR EVEN ISOLATED IFR WILL BE POSSIBLE IN HEAVIER SHOWERS AND EMBEDDED STORMS. GIVEN LOW CONFIDENCE ON THUNDER COVERAGE...VCTS/CB HAVE BEEN LEFT OUT ATTM. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY EVENING AND AGAIN ON THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO NEAR TERM...CONIGLIO SHORT TERM...CONIGLIO LONG TERM...AR AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
153 AM EDT SAT MAR 17 2012 .SYNOPSIS... SEVERAL WEAK UPPER LEVEL DISTURBANCES WILL BRING A CHANCE OF THUNDERSTORMS THROUGH THE WEEKEND. HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE FIRST PART OF NEXT WEEK WITH TEMPERATURES REMAINING WELL ABOVE. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MOST OF SHOWERS OVER KENTUCKY ASSOCIATED WITH WEAK LOW PRESSURE HAVE DISSIPATED WITH LOSS OF DAYTIME HEATING. WILL HANG ON TO SOME LOW POPS ACROSS THE SOUTH THROUGH THE OVERNIGHT HOURS THOUGH JUST IN CASE REDEVELOPMENT OCCURS AS SUGGESTED BY THE HRRR MODEL. EXPECT OVERNIGHT LOWS GENERALLY IN THE MID TO UPPER 50S. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... THE MID/UPPER LEVEL RIDGE WILL TRY TO BUILD UP ACROSS THE AREA THROUGH THE WEEKEND...BUT IT WILL BE TEMPERED BY SEVERAL WEAK SHORT WAVES RIDING OVER THE RIDGE. WITH A WARM AND SEASONABLY MOIST AIRMASS IN PLACE...THIS SHOULD BE ENOUGH TO TRIGGER AT LEAST SCATTERED THUNDERSTORM ACTIVITY ON AND OFF SATURDAY INTO SUNDAY. RIGHT NOW IT LOOKS LIKE THE BEST FORCING WILL MOVE ACROSS THE AREA ON SUNDAY BUT MODELS HAVE A DIFFICULT TIME WITH THE TIMING/STRENGTH OF THESE SHORT WAVES. WILL THEREFORE KEEP POPS IN THE CHANCE CATEGORY THROUGH MUCH OF THE WEEKEND. DEEP LAYER SHEAR REMAINS RELATIVELY WEAK...ALTHOUGH IT DOES BEGIN TO INCREASE A BIT FROM THE SOUTHWEST THROUGH THE DAY ON SUNDAY. THEREFORE WOULD THINK SEVERE THREAT WILL REMAIN RELATIVELY LOW THROUGH THE WEEKEND. WITH FAIRLY LIGHT FLOW...LOCALLY HEAVY RAIN SHOULD BE THE MAIN ISSUE. TEMPERATURES WILL REMAIN DEPENDENT ON AMOUNT OF CLOUD COVER AND PCPN. WILL KEEP HIGHS MAINLY IN THE UPPER 70S...BUT IF WE END UP WITH MORE SUN...THESE MAY BE A LITTLE LOW. && .LONG TERM /MONDAY THROUGH FRIDAY/... RIDGING WILL AMPLIFY ACROSS THE REGION IN RESPONSE TO A DEEP TROUGH MOVING SLOWLY EAST ACROSS THE ROCKIES....BRINGING INCREASING HEIGHTS AND TEMPERATURES ALOFT FOR MONDAY AND TUESDAY. THIS WILL RESULT IN THE WARMEST TEMPERATURES OF THE WEEK...POSSIBLY APPROACHING RECORD VALUES. ONE INHIBITING FACTOR FOR TEMPERATURES RISING HIGHER THAN FORECAST WILL BE THE POTENTIAL AMOUNTS OF MID AND UPPER LEVEL CLOUD COVER...WHICH THE MODELS ARE NOT IN AGREEMENT ON AT THIS TIME. THE TROUGH TO OUR WEST WILL CLOSE OFF INTO AN UPPER LOW AS IT SLOWLY MOVES EASTWARD ACROSS THE PLAINS DURING THE MID WEEK. MODELS CONTINUE TO BRING THE LOW FINALLY ACROSS THE OHIO VALLEY LATE NEXT WEEK. THERE CONTINUE TO BE TIMING DIFFERENCES OF WHEN THIS WILL OCCUR. HOWEVER...AS IT DOES SO...CHANCES FOR PRECIPITATION WILL INCREASE. HAVE SPLIT THE DIFFERENCE BETWEEN THE GFS AND ECMWF IN BRINGING BEST POPS TO THE AREA AT 00Z FRIDAY. TEMPERATURES WILL RETURN TO MORE SEASONABLE VALUES ONCE THE LOW ARRIVES IN OUR AREA. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... ANOTHER NIGHT OF SOMEWHAT CONFLICTING MODEL GUIDANCE PUTS THE CONFIDENCE OF THE FORECAST IN A LOW STATE. FLOW REMAINS SOUTHERLY OVER THE OHIO VALLEY AND THE UNSEASONABLY MILD AND MOIST AIRMASS WILL BE ABLE TO SUPPORT THUNDERSTORM DEVELOPMENT AND PROPOGATION AT PRETTY MUCH ANY TIME...HEIGHTENED WITH THE DAYTIME HEATING. A MEAN UPPER LEVEL RIDGE WILL HAMPER WIDESPREAD CONVECTION BUT A SHORTWAVE OVER ILLINOIS IS PROGGED TO UNDERCUT THIS RIDGE AT SOME POINT IN TIME THIS AFTERNOON AND EARLY EVENING. KEPT THE VICINITY THUNDERSTORMS IN THE FORECAST THIS AFTERNOON BUT IT WON`T BE APPARENT UNTIL THE MID LEVEL LOBE OFF OF THE MAIN SHORTWAVE DEVELOPS TO SEE WHERE AND WHICH TAF SITES WILL PRIMARILY BE AFFECTED. FORECAST IS VFR ASIDE FROM SHALLOW GROUND FOG THROUGH DAYBREAK THIS MORNING. OUTLOOK...THUNDERSTORMS ARE POSSIBLE SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...CONIGLIO/JGL SHORT TERM...JGL LONG TERM...LATTO AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
900 PM PDT FRI MAR 16 2012 .SYNOPSIS...ANOTHER ROUND OF WIND AND RAIN FOR THE REGION TONIGHT BUT SHOULD SEE MORE TRANQUIL BUT COOL WEATHER FOR THIS WEEKEND. HOWEVER...AS SPRING PREPARES TO ARRIVE NEXT WEEK...OLD MAN WINTER IS PREPPING TO GIVE SOME SERIOUS FINAL GOODBYES TO THE PAC NW...WITH MORE RAIN...WIND...AND LOW SNOW LEVELS NEXT WEEK. && .SHORT TERM...RATHER IMPRESSIVE LOW JUST OFF THE S OREGON COAST THIS EVENING...WITH OCCLUDED FRONT BUCKLED INTO SW OREGON. RUC MODEL AND FOR MOST PART NAM MODEL SEEM TO BE DOING BEST WITH LOW AND ITS MOVEMENT INTO OREGON. RAIN SHIELD HEADED N BUT RAINFALL WILL BE HEAVIEST OVER THE WILLAMETTE VALLEY WEST INTO THE COAST RANGE AS FRONT PRECIP HEAD N ACROSS AREA THIS EVENING. SNOW LEVELS STILL NEAR 3000 FEET. SO DESPITE PRECIP ACROSS REGION...LOOKS THAT WILL NOT BE HEAVY ENOUGH TO COOL THE AIR MASS DRASTICALLY. STILL...WILL SEE ACCUMULATING SNOW DOWN TO BETWEEN 1000 AND 1200 FEET IN THE N COAST RANGE AND WILLAPA HILLS. THIS SAID...WILL MAINTAIN WINTER WEATHER ADVISORY THERE FOR 2 TO POSSIBLY AS MUCH AS 6 INCHES OF NEW SNOW OVERNIGHT. NO SNOW ON THE COAST...AS JUST STAYS TOO WARM. AS FOR SNOW IN THE COLUMBIA GORGE...WELL LOOKS UNLIKELY. TEMPS ARE STILL IN THE MID 40S IN THE GORGE...AND IN THE LOWER 50S AT THE DALLES. WITH LACK OF ANY COLD AIR TO THE EAST...SO WILL KEEP SNOW OUT OF THE LOWER ELEVATIONS IN THE GORGE. MAY SEE SNOW BRIEFLY DOWN TO 1000 FEET SAT AM...BUT ACCUMULATIONS LIGHT IF ANY. OTHER CONCERN RAISED IS GUSTY WINDS. WITH TRACK OF THE LOW...BEST GRADIENT JUMPS ARE OCCURRING OVER SW OREGON. THESE WILL TRANSLATE ACROSS REST OF THE REGION OVERNIGHT...BUT NOT AS STRONG AS EARLIER INDICATED. GUSTY S WINDS OF 15 TO 25 MPH...WITH GUSTS 35 TO 45 MPH ARE LIKELY LATER THIS EVENING OVER S WILLAMETTE VALLEY INTO THE LANE COUNTY CASCADES...THEN SPREAD NORTHWARD OVERNIGHT. HOWEVER...WINDS WILL MUCH LESS OVER THE N AS GRADIENTS WEAKEN LATER TONIGHT. CORE OF STRONGEST WINDS WILL REMAIN FROM FAR S LANE COUNTY UP TO SANTIAM PASS...WITH GUSTY WINDS EXPECTED ON EAST SLOPES OF CASCADES LATER TONIGHT AND SAT. UNSETTLED SHOWERY WEATHER FOR SATURDAY AND SUNDAY AS THE UPPER TROUGH PUSHES OVER THE PAC NW. BUT AT LEAST NO STRONG WINDS AND SNOW LEVELS REMAIN IN THE MOUNTAINS WITH NO THREAT OF LOWLAND SNOW. WILL HAVE SOME THREAT OF SMALL HAIL WITH SOME SHOWERS. SHOWERS DECREASE SATURDAY NIGHT. COOLER AIR ARRIVES SAT NIGHT AND SUN AS THE UPPER TROUGH PASSES INTO EASTERN OREGON...WITH SNOW LEVELS BACK DOWN BETWEEN 700 AND 1000 FEET. HOWEVER...MOISTURE BECOMES QUITE LIMITED SO ANY THREAT OF LOW SNOW MAY BE WELL MITIGATED. ROCKEY. && .LONG TERM...FOLLOWING A WEEKEND OF MAINLY LIGHT SHOWER ACTIVITY...THE STORM TRACK IS FCST TO MOVE BACK NORTH OVER THE PAC NW STARTING ON TUE. FLAT RIDGING WILL REMAIN OVER THE REGION ON MON NIGHT...BUT A SYSTEM TO THE NORTH IS FCST TO SWING A WARM FRONT INTO THE DISTRICT LATE MON INTO TUE MORNING. EXPECT SOME GUSTY COASTAL WINDS AND RAPIDLY RISING SNOW LEVELS AS WINDS TURN SOUTHERLY. MODEL SOLUTIONS DIVERGE FOLLOWING THE TUE SYSTEM. THE 12Z ECMWF BRINGS ANOTHER STRONGER SYSTEM THROUGH ON WED INTO EARLY THU. IF THIS VERIFIES...IT LOOKS LIKE MORE HEAVY RAIN AND STRONG COASTAL WINDS. THE 12Z GFS DIGS THE BULK OF THE ENERGY FURTHER SOUTH OF US. THE LAST FEW RUNS OF THE ECMWF HAVE BEEN CONSISTENT WITH THIS WED FEATURE...SO LEANED TOWARDS THIS SOLUTION FOR THE LONG TERM FCST. HEADING INTO THE END OF THE WEEK AND NEXT WEEKEND...THE MODELS TEND TO DIG OUT A DEEP TROUGH OVER THE ENTIRE WEST COAST. IT IS LOOKING MUCH LIKE THE PATTERN THAT WE WILL SEE THIS WEEKEND. JFP && .AVIATION...MAINLY VFR IN THE VALLEY AS THE FIRST BATCH OF RAIN MOVES FROM SOUTH TO NORTH. PRONOUNCED DRY SLOT ON SATELLITE/RADAR AND CONFIRMED BY OBS AT KEUG INDICATING THE PRECIP ONLY LASTS ABOUT 3 HOURS OR SO. WE MAY SEE BRIEF MVFR WITH THE RAIN BUT NOT FOR LONG. MVFR LOOKS TO MOVE BACK IN AS THE LOW PRES SYSTEM ASSOCIATED WITH THE RAIN MOVES NORTH AND EAST. WE ARE STARTING TO SEE SOME OF THAT WITH THE LOWER VFR AND HIGHER MVFR CIGS AT TIMES IN THE CENTRAL/SOUTH VALLEY. CONDITIONS BECOME MUCH MORE UNSTABLE LATE TONIGHT/EARLY SATURDAY...WHICH WILL BRING THE RETURN TO VFR WITH OCCASIONAL MVFR IN ANY HEAVIER SHOWERS. EXPECT BRIEF GUSTY SOUTHERLY WINDS LATER TONIGHT. AT THE COAST...EXPECT A MIX OF VFR AND MVFR AT THE COAST AS DEFORMATION PRECIP LINGERS OVERNIGHT AND THEN SHIFTS INLAND EARLY SATURDAY. EXPECT THE HEAVIEST PRECIP RATES OVER THE COAST RANGE. WITH SOME COLD AIR WRAPPING IN...NOT SUPER COLD...IT IS NOT OUT OF THE QUESTION THAT SOME SNOW MAY BE MIXED IN...BUT THE CHANCE IS VERY LOW. LATEST 0Z COBB OUTPUT (TOP-DOWN METHODOLOGY FOR PRECIP TYPE) HAS BEEN BACKING OFF ON ANY SNOW MIXING IN AT KAST. THEN A RETURN TO SHOWERS AND MVFR AT TIMES. POSSIBLY A THUNDERSTORM IN THE UNSTABLE AIR MASS. KPDX AND APPROACHES...VFR CONDITIONS PREVAIL THROUGH TONIGHT. MVFR CIGS ARE POSSIBLE TONIGHT AS SHOWERS GRADUALLY INCREASE. EXPECT WINDS TO PICK UP AFTER 09Z...WITH GUSTS NEAR 25 KTS LATE TONIGHT/EARLY SAT MORNING. SHOWERS WITH VFR AND OCCASIONAL MVFR ON SATURDAY. && .MARINE...WINDS ARE FAIRLY LIGHT OVER WATERS NOW...THOUGH EXPECT NORTHERLY SMALL CRAFT CRITERIA GUSTS NEAR 25 KTS TONIGHT WITH A FEW GUSTS NEAR 30 KTS DURING THE 6Z TO 12 Z PERIOD AS A STRONG BUT WEAKENING SURFACE LOW PUSHES INLAND. EXPECT LITTLE CHANGE IN SEAS THROUGH SAT...WITH SEAS REMAINING AROUND 12 TO 13 FT. WINDS REMAIN BELOW 20 KT FOR THE REST OF THE WEEKEND WITH WEAK HIGH PRES IN PLACE. ANOTHER ROUND OF GALES IS POSSIBLE MONDAY NIGHT AS A STRONG WARM FRONT MOVES THROUGH WITH A STRONG SURFACE LOW WELL TO THE NORTH. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...WIND ADVISORY UNTIL 6 AM PDT SATURDAY FOR CENTRAL WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY. WINTER WEATHER ADVISORY UNTIL 9 AM PDT SATURDAY FOR COAST RANGE OF NORTHWEST OREGON. WA...WINTER WEATHER ADVISORY UNTIL 9 AM PDT SATURDAY FOR WILLAPA HILLS. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 PM PDT SATURDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT SATURDAY FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 5 PM PDT SATURDAY. && $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
944 PM CDT SUN MAR 18 2012 .UPDATE... EXCEPTIONALLY WARM EVENING CONTINUES THIS EVENING AS STRONG LLV SOUTHERLY FLOW CONTINUES. ABR STILL 72F AS OF THIS WRITING WITH NO REAL END IN SITE TO AT LEAST MODERATE SOUTH WINDS TONIGHT. RAISED OVERNIGHT LOWS TO THE WELL PERFORMING BCCONSRAW GUIDANCE LEVELS BUT THEY MAY NOT BE WARM ENOUGH. 53F IS THE ALL TIME MARCH RECORD FOR HIGHEST MINIMUM TEMPERATURE AT ABERDEEN. WITH SOUTH WINDS CONTINUING...THANKS TO A STRENGTHENING LLJ... AND HIGH CLOUDS INCREASING FROM THE SOUTH...EXPECT THAT TEMPS WILL STRUGGLE TO FALL BELOW 60F AT MANY LOCATIONS BY MORNING. ALSO ADDED SLIGHT CHANCE FOR THUNDERSTORMS OVER THE SOUTHWEST ZONES FOR THE REMAINDER OF THE NIGHT GIVEN LATEST HRRR RUNS AND RADAR OBSERVATIONS SHOWING THUNDERSTORMS PROPAGATING NWD THROUGH NORTH CENTRAL NEBRASKA. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT MODELS ARE NOT BEING OVERLY HELPFUL WITH THE LACK OF CONSISTENCY ON THE CURRENT ROCKY MOUNTAIN LOW AND THE ASSOCIATED COLD FRONT THAT WILL MOVE THROUGH THE DAKOTAS ON MONDAY. THIS DEVELOPING LOW WILL PROGRESS NORTH INTO CANADA AND THEN EAST TRACKING A 65 KT LLJ OVER THE DAKOTAS TONIGHT. KEPT A SMALL CHANCE OF TSTORMS ACROSS CODINGTON/HAMLIN/DEUEL COUNTIES LATE TONIGHT AS THE JET PROGRESSES FARTHER EAST. WITH ABUNDANT LOW LEVEL MOISTURE IN PLACE AND ABOUT 1000 J/KG CAPE SOMETHING MAY KICK OFF. DID NOT PUT ANY TSTORMS FARTHER WEST DUE TO LACK OF MOISTURE THIS EVENING. AHEAD OF THE FRONT ON MONDAY THERE ARE TWO AREAS OF CONCERN. ONE WILL BE THE STRONG SOUTHERLY WINDS. WITH PRESSURE FALLS OF AROUND 15 TO 20 MB AND SOME CAA THIS MAY WARRANT A WIND ADVISORY...BUT WILL PUNT THIS DECISION TO THE NEXT SHIFT. AS THE WINDS INCREASE...RH WILL ALSO DROP WEST OF THE MISSOURI RIVER TO 15 TO 20 PERCENT. SO THE SECOND CONCERN WILL BE TO CONSIDER ANOTHER RFW FOR MONDAY...THOUGH FARTHER WEST THAN WHAT IS IN PLACE TODAY. SOME MORE TSTORMS ARE POSSIBLE ON MONDAY OUT AHEAD OF THE FROPA WITH SHOWERS LINGERING BEHIND. TEMPERATURES WILL FALL OFF A BIT WITH ADDED CLOUD COVER TO AROUND 70 DEGREES ACROSS THE REGION. BEHIND THE COLD FRONT HIGHS WILL REACH ONLY INTO THE UPPER 50S ON TUESDAY. .LONG TERM...WEDNESDAY THROUGH SUNDAY MAIN FEATURE TO WATCH IN THE EXTENDED PERIOD IS THE CUTOFF LOW THAT WOBBLES ACROSS THE CENTRAL PLAINS. RECENT MODEL RUNS HAVE BROUGHT THIS FEATURE A BIT FARTHER NORTH WHICH ALLOWS OUTER RAIN BAND TO REACH THE EASTERN CWA. SLIGHT CHANCE POPS HAVE BEEN INSERTED ACROSS THE EASTERN CWA THURSDAY INTO FRIDAY. OTHERWISE...THIS IS ABOUT THE ONLY FEATURE TO DEAL WITH DURING THE FORECAST PERIOD. TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL WITH READINGS IN THE 60S FOR MOST LOCATIONS. && .AVIATION... 00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS FOR KABR AND KATY...LOW LEVEL MOISTURE WILL MAKE A RETURN LATER THIS EVENING SO EXPECT AREAS/PATCHY OF MVFR/IFR CIGS TO DEVELOP ONCE AGAIN AFTER 09Z MONDAY. THESE CIGS SHOULD GRADUALLY DISSIPATE LATE MONDAY MORNING. BY MONDAY AFTERNOON AND EVENING...COULD SEE A FEW HIGH BASED -SHRAS/-TSRAS VCNTY KATY AND KABR. SOUTHERLY WINDS WILL INCREASE FROM 25 TO 35 KTS DURING THE AFTERNOON. FARTHER WEST AT KMBG AND KPIR...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE OVERNIGHT HOURS. STRONG SOUTHERLY SFC WINDS ARE EXPECTED THROUGH THE EVENING HOURS...RANGING FROM 25 TO 35 KTS. THE STRONG WINDS WILL SUBSIDE AFTER APPROXIMATELY 06Z MONDAY AND THEN MAKE A RETURN MONDAY AFTERNOON. && .FIRE WEATHER... EXTREME FIRE CONDITIONS TOPS FORECAST PRIORITIES AGAIN TODAY. RECORD HIGH TEMPERATURES AGAIN POSSIBLE. A HUMID AIRMASS HAS SET UP IN THE EAST...WHILE WEST IS LESS HUMID AND SHOULD MIX OUT MORE EFFICIENTLY. THAT WILL CREATE A TIGHT NORTH TO SOUTH GRADIENT IN THE HUMIDITY TODAY...BETWEEN MOBRIDGE AND ABERDEEN AND BETWEEN PIERRE AND HURON. HIGH WINDS DEPEND ON THE DEGREE OF MIXING WITH STRONG WINDS ABOVE THE SURFACE ABLE TO MIX DOWN MORE EFFICIENTLY IN SOUTH CENTRAL COUNTIES. A LOW LEVEL JET WILL FORM AHEAD OF OUR SYSTEM TONIGHT...SO WHILE WINDS WILL LESSEN...THEY WILL REMAIN GUSTY...WHICH WILL ALSO KEEP TEMPERATURES MILD OVERNIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CHURCH SHORT TERM...WISE LONG TERM...TMT AVIATION...CHURCH FIRE WEATHER...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
823 PM MDT SUN MAR 18 2012 .UPDATE...02Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST MT AND COLD FRONT INTO CENTRAL CO. WATER VAPOUR HAD SHORTWAVE OVER SOUTHEAST WY/NE PANHANDLE...ON THE NOSE OF A 110KT JET. THIS WAVE WILL RAPIDLY MOVE NORTH TONIGHT PUSHING COLD FRONT INTO THE CWA FROM THE WEST. AHEAD OF IT...GUSTY SOUTHWEST WINDS WILL CONTINUE BUT DIURNAL BOUNDARY LAYER EFFECTS ARE STARTING TO DECOUPLE 50KT LOW LEVEL JET FROM MIXED LAYER. THUS WILL ALLOW WIND HEADLINES TO EXPIRE ON SCHEDULE AT 03Z. MOIST TONGUE HAD 50-PLUS DEW POINTS OVER SOUTH CENTRAL SD INTO CENTRAL NE. NARROW AXIS OF INSTABILITY ALLOWING FOR SOME CONVECTION. FURTHER WEST...SOME -SHRA NOTED WITH MAIN SYNOPTIC FORCING...BUT LAPSE RATES STEEP ENOUGH TO LEAVE SMALL CHANCE OF THUNDER IN THERE THROUGH 06Z. WITH THESE TRENDS IN MIND AND HRRR SOLUTIONS...WILL BRING SOME POPS CWA-WIDE THIS EVENING AND ACROSS THE NORTH THROUGH EASTERN PORTIONS OF THE CWA OVERNIGHT. && .FIRE WEATHER...RELATIVE HUMIDITIES WILL RECOVER ENOUGH TO ALLOW RED FLAG WARNING TO EXPIRE ON-TIME AT 03Z. && .AVIATION...00Z TAFS UPDATE VFR CONDITIONS WILL CONTINUE THROUGH MONDAY AFTERNOON. LOW PRESSURE OVER SOUTHEAST MT WILL MOVE NORTHEAST INTO WESTERN ND. THIS WILL KEEP A TIGHT PRESSURE GRADIENT IN PLACE WITH GUSTY WINDS THROUGH MOST OF TONIGHT/MONDAY AT TIMES. AN ISOLATED GUSTY -SHRA/-TSRA CANNOT BE RULED OUT THIS EVENING...AND THEN ISOLATED SHOWERS ACROSS THE NORTH INTO CENTRAL SD OVERNIGHT. && .PREV DISCUSSION... /ISSUED 653 PM MDT SUN MAR 18 2012/ UPDATE...00Z SURFACE ANALYSIS HAD LOW OVER CENTRAL WY WITH DECENT GRADIENT OVER THE CWA. BEST GRADIENT FROM SOUTHWEST THROUGH SOUTH CENTRAL SD WHERE CONTINUED MIXING IS ALLOWING VERY WINDY CONDITIONS TO PERSIST. FURTHER NORTH WHERE CI/CS SHIELD DROPPED IN DURING THE AFTERNOON...WINDS ARE JUST BREEZY/WINDY...SO WILL CANCEL WIND ADVISORY FOR THOSE AREAS. 00Z KUNR SOUNDING SHOWED IMPRESSIVE LAPSE RATES AGAIN. WATER VAPOUR HAD MAIN SHORTWAVE ENERGY OVER NORTH CENTRAL CO/SOUTHEAST WY ON NOSE OF 110KT JET. THIS WILL PUSH LOW NORTHEAST TONIGHT...ALLOWING COLDER AIR TO FILTER OVER WESTERN AREAS. STRONG WIND FIELD MAY SUPPORT GUSTY WINDS NEAR ANY -SHRA/-TSRA THAT DEVELOP OVER NORTHEASTERN WY AND SOUTH CENTRAL SD TONIGHT. PREV DISCUSSION... /ISSUED 234 PM MDT SUN MAR 18 2012/ TONIGHT THROUGH TUESDAY NIGHT DEEP LONG WAVE WESTERN CONUS TROUGH CONTINUES ITS SLOW MARCH TO THE NE...WITH SFC PRESSURE FALLS ONGOING ACROSS WY AND SOUTHERN MT AS A PORTION OF THE UPPER TROUGH FRACTURES AND BEGINS TO ADVECT NE. THIS STRONG IMPULSE WILL MERGE WITH A NW CONUS ADVANCING TROUGH AND SUPPORT SFC LOW ADVECTION NE INTO THE CANADIAN PLAINS. HEIGHT FALLS CONTINUE INTO WY WITH DESTABILIZATION ONGOING THERE PER LL WARMING AND UPPER LEVEL COOLING. A FEW HIGH BASED SHRA AND ISOLD TS HAVE DEVELOPED FARTHER WEST OUTSIDE THE FA...WHERE A LITTLE BETTER UPPER SUPPORT IS IN PLACE. SFC BASED INSTABILITY WILL CONTINUE TO INCREASE THIS AFTERNOON OVER NE WY...WITH THE SFC TROUGH EXPECTED TO APPROACH THE REGION...SUPPORTING LOW CHANCE POPS INTO THIS EVENING THERE...AND POSSIBLY INTO THE WESTERN BLACK HILLS. OTHERWISE...WARM WINDY CONDITIONS ARE DEVELOPING ACROSS THE REGION...AS MIXING HEIGHTS INCREASE AND LL FLOW RESPONDS TO THE HEIGHT FIELD. WINDS WILL CONTINUE TO INCREASE THROUGH THE AFTERNOON WITH WIND ADV CRITERIA EXPECTED TO BE REACHED LATE THIS AFTERNOON AND EARLY EVENING. STRONG 125+ KNOT UPPER LEVEL JETLET ASSOCIATED WITH THE MAIN UPPER TROUGH OVER THE SW CONUS...WILL ADVECT NNE TOWARD THE REGION TONIGHT...WITH THE NOSE OF THE UPPER JET EXPECTED TO ADVECT OVER THE FA. LEFT EXIT REGION INDUCED UPWARD ASCENT WILL HELP IN FURTHER DEEPENING THE SFC LOW...IN ADDITION TO ACCENTUATING THE LLJ. FORECAST MODELS ARE STILL INDICATING INCREASING DEEPER MOISTURE OVER SOUTH CENTRAL SD...GIVEN H85 THETA-E RISES INTO THE 320-330K RANGE THROUGH 06Z...AHEAD OF THE LEAD SFC TROUGH. GIVEN THE POSITION OF THE UPPER JET RIGHT EXIT REGION/INCREASING LL MOISTURE/AND INCREASING LARGE SCALE ASCENT...CANNOT RULE OUT AN ISOLATED SHRA OR TS OVER THE FAR SE. HAVE INCORPORATED A 6 HOUR PERIOD OF TS MENTION THERE. OTHERWISE...DIURNALLY DRIVEN CONVECTION CHANCES OVER NE WY WILL WANE THROUGH EVENING. AFOREMENTIONED UPPER IMPULSE WILL PHASE WITH A NORTHERN STREAM COUNTERPART AND SUPPORT A COLD FRONT INTO THE REGION MONDAY. CONTINUED WEAK UPGLIDE OVER WESTERN SD MAY SUPPORT A LIGHT SHOWER OVER THE FAR SE...WITH CONVECTIVE SHOWERS EXPECTED TO DEVELOP ALONG AND AHEAD OF THE SFC COLD FRONT IN NE WY...LIKELY DIURNALLY ENHANCED. COOLING PROFILES SUGGEST RAIN MAY MIX WITH SNOW DURING THE AFTERNOON. HOWEVER...SFC TEMPS IN THE 40S WILL PRECLUDE ACCUMS. SHOWER ACTIVITY WILL WANE THROUGH EVENING OVER NE WY AND THE WESTERN/NORTHERN BLACK HILLS...WITH ANY RESIDUAL SHRA TRANSITIONING TO SNOW. SOME LIGHT ACCUMS ARE POSSIBLE. OTHERWISE...SOUTHERLY WINDS WILL BE GUSTY AHEAD OF THE SFC COLD FRONT MON...WITH WINDS INCREASING TO 20 TO 30 MPH OVER THE NORTHERN HALF OF WESTERN SD. WIND ADV CRITERIA MAY BE REACHED CLOSER TO THE ND BORDER GIVEN SIG PRESSURE FALLS ONGOING OVER NE MT. SFC COLD WILL PUSH EAST OF THE REGION...COMING THROUGH DRY OVER SD AS THE MAIN LOBE OF LARGE SCALE ASCENT SHIFTS NORTH INTO MT/ND/SK. DRY BUT STILL MILD WEATHER IS ON TRACK FOR TUES...WITH MOSTLY CLEAR SKIES EXPECTED. EXTENDED...A MAINLY DRY AND MILD WEATHER PATTERN IS ANTICIPATED FOR THE MIDDLE AND LATTER PART OF THE WEEK. HOWEVER...AN UPPER LEVEL LOW IS PROGGED TO BE IN PLACE OVER THE SOUTHERN HIGH PLAINS MIDWEEK AND SLOWLY MOVE NORTHEAST ACROSS THE PLAINS LATE IN THE WEEK. DEPENDING ON THE ULTIMATE MOVEMENT OF THE LOW...THERE COULD BE A CHANCE FOR SHOWERS OVER MAINLY SOUTHEASTERN PORTIONS OF THE CWA THURSDAY INTO FRIDAY. VARIOUS MEDIUM RANGE MODELS DIFFER ON TIMING AND MOVEMENT OF THE SYSTEM WITH A STRONG RIDGE TO THE EAST OF THE REGION. GFS BRINGS IT THE FURTHEST NORTH...WITH SHOWERS POSSIBLE OVER PORTIONS OF SOUTHWESTERN INTO CENTRAL SD. WILL GO WITH THE CONSENSUS OF THE MODELS AND KEEP DRY FOR NOW. OTHERWISE...TEMPS WILL BE WELL ABOVE AVERAGE THROUGH THE PERIOD...WITH HIGHS IN THE 60S AND 70S ON MOST DAYS...A BIT COOLER OVER THE BLACK HILLS. FIRE WEATHER...RED FLAG CONDITIONS HAVE DEVELOPED ACROSS MUCH OF NORTHEASTERN WY AND WESTERN SD THIS AFTERNOON AS WINDS INCREASE AND HUMIDITIES DROP TO NEAR OR BELOW 15 PERCENT. THESE CRITICAL FIRE WEATHER CONDITIONS WILL PERSIST INTO EARLY THIS EVENING BEFORE HUMIDITIES SLOWLY RISE AND WINDS GRADUALLY DECREASE. ON MONDAY...GUSTY SOUTHWESTERLY WINDS WILL DEVELOP AHEAD OF AN APPROACHING COLD FRONT. TEMPERATURES WILL BE LOWER...BUT A VERY DRY AIRMASS IN PLACE WILL DROP RELATIVE HUMIDITIES TO AROUND 15 PERCENT ACROSS MUCH OF WESTERN AND SOUTH CENTRAL SOUTH DAKOTA IN THE AFTERNOON. CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TO DEVELOP OVER THESE AREAS IN THE AFTERNOON AND PERSIST UNTIL AROUND SUNSET. A COLD FRONT WILL FINALLY MOVE THROUGH THE AREA MONDAY NIGHT... BRINGING LOWER TEMPERATURES AND HIGHER HUMIDITIES FOR TUESDAY. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR BADLANDS AREA- CENTRAL SOUTH DAKOTA PLAINS-NORTHERN BLACK HILLS- NORTHWESTERN SOUTH DAKOTA PLAINS-SOUTH CENTRAL SOUTH DAKOTA- SOUTHERN BLACK HILLS-SOUTHWESTERN SOUTH DAKOTA. RED FLAG WARNING FROM 11 AM TO 8 PM MDT MONDAY FOR BADLANDS AREA- CENTRAL SOUTH DAKOTA PLAINS-NORTHERN BLACK HILLS- NORTHWESTERN SOUTH DAKOTA PLAINS-SOUTH CENTRAL SOUTH DAKOTA- SOUTHERN BLACK HILLS-SOUTHWESTERN SOUTH DAKOTA. WIND ADVISORY UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR BENNETT-JACKSON-MELLETTE-SHANNON-TODD-TRIPP. WY...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR LOWER ELEVATIONS OF CROOK AND WESTON COUNTIES-NORTHERN CAMPBELL- SOUTHERN CAMPBELL-WYOMING BLACK HILLS. && $$ SHORT TERM...HELGESON LONG TERM....WFO UNR AVIATION...HELGESON
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1239 PM CDT SAT MAR 17 2012 .UPDATE... SEE UPDATED AVIATION DISCUSSION BELOW. UPDATED FIRE WEATHER WATCH TO RED FLAG WARNING ACROSS CENTRAL SOUTH DAKOTA FOR SUNDAY AFTERNOON. STRATUS CLOUDS ARE QUICKLY FILLING IN AND EXPANDING ACROSS THE EASTERN CWA AS LOW LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD. SEVERAL CHANGES NEEDED TO WEATHER ELEMENTS THIS MORNING TO ACCOUNT FOR THIS. INCREASED SKY COVER QUITE A BIT THROUGH THE MORNING AND INTO THE AFTERNOON. RUC SOUNDINGS ON BUFKIT PICKING UP ON THESE CLOUDS AND WOULD SUGGEST STRATUS STICKING AROUND INTO THE AFTERNOON BEFORE STRATOCU-ING OUT. THIS ALSO THROWS A WRENCH INTO THE TEMP RISE THIS MORNING SO ADJUSTED HOURLY READINGS. DID NOT MESS WITH HIGHS AT THIS TIME SINCE BY MID TO LATE AFTERNOON STILL EXPECTING CLOUDS TO BREAK UP AND TEMPS TO RISE. WILL MONITOR THIS THOUGH. DEWPOINTS RISING THROUGH THE 50S ACROSS THE EASTERN CWA. FOG STILL HANGING AROUND IN SPOTS AS WELL SO EXTENDED MENTION OF THIS FOR A COUPLE MORE HOURS. FARTHER WEST...PLENTY OF SUNSHINE ALL DAY WITH VERY LOW RH VALUES IN THE AFTERNOON LEADING TO HIGH TO VERY HIGH FIRE DANGER. STILL APPEARS WINDS WILL NOT BE STRONG ENOUGH TO WARRANT AND FIRE HEADLINES FOR THIS AFTERNOON. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH MONDAY PRESSURE GRADIENT CONTINUES TO RELAX...WHICH WILL RESULT IN LIGHTER WINDS TODAY...LESS EFFICIENT MIXING...AND HIGHER HUMIDITY. A POCKET OF HIGHER MOISTURE AIR SITS ACROSS THE EAST AND WILL EXPAND WESTWARDS WITH SOUTH/SOUTHEAST WINDS TODAY...SO TEMPERATURES WILL BE SOMEWHAT LESS EXTREME DESPITE SIMILAR TEMPERATURES ALOFT. AS UPPER TROF CONTINUES TO SLOWLY PUSH EAST...WILL SEE LEE CYCLOGENISIS ACROSS WESTERN SOUTH DAKOTA...INCREASING THE GRADIENT OVERNIGHT ALONG WITH WEAK LOW LEVEL JET FORMATION. A TIGHT HUMIDITY GRADIENT WILL CONTINUE ACROSS THE AREA OVERNIGHT AS WELL. AS THE SYSTEM SHIFTS EAST SUNDAY...PRESSURE GRADIENT INTENSIFIES ALONG WITH A 50-60KT H85 JET MAX. HAVE ISSUED A FIRE WEATHER WATCH GIVEN DEEP MIXING WHICH WILL HELP MIX OUT SHALLOW MOISTURE IN THE WEST. THERE IS PLENTY OF UNCERTAINTY OVER HOW EFFICIENTLY THIS MOISTURE WILL MIX OUT IN THE EAST. WINDS WILL STAY UP OVERNIGHT SUNDAY/EARLY MONDAY AS WELL. AS FOR PRECIPITATION CHANCES...WITH WARM LOW LEVEL AIRMASS...WILL SEE STEEP LAPSE RATES ALOFT THROUGH MOST OF THE PERIOD. MOISTURE IS RELATIVELY SHALLOW AND DYNAMICS ARE LACKING FOR MOST OF THE PERIOD TO WARRANT MENTION OF THUNDER...UNTIL LATE SUNDAY. A WEAK WAVE IN SOUTHWEST FLOW COULD SUPPORT HIGH BASED ALTO CUMULUS. MORE WIDESPREAD CONVECTION IS POSSIBLE WITH A STRONGER WAVE LIFTING NORTH WITH A SLOW MOVING NORTH/SOUTH ORIENTED COLD FRONT PROVIDING THE FOCUS FOR THUNDERSTORMS. .LONG TERM...MONDAY NIGHT THROUGH FRIDAY THE THEME DURING THE EXTENDED IS COOL DOWN. MONDAY NIGHT...A COLD FRONT IS WORKING ACROSS THE EASTERN HALF OF FORECAST ZONES...WITH NOTABLY COOLER/DRIER AIR ADVECTING IN BEHIND FOR TUESDAY AND WEDNESDAY. FOLLOWED THE PREFERRED ECMWF SOLUTION FOR HANDLING THE CLOSED UPPER LOW ENERGY OVER THE LOWER/MID-MISSISSIPPI VALLEY REGION...WHICH IS TO PROPAGATE THE LOW EASTWARD AWAY FROM THIS REGION AS THE WEEK WEARS ON...VERSUS THE GFS SOLUTION THAT STILL TRIES TO DRAW THE CLOSED UPPER LOW NORTHWARD TOWARD IOWA. THE ECMWF ACTUALLY DOES TRY TO BRING A BIT OF RETURN FLOW WARMTH BACK INTO THE REGION ON THURSDAY BEFORE A LOW PRESSURE SYSTEM IN THE FAST WESTERLY FLOW ACROSS SOUTHERN CANADA DRAGS A COLD FRONT ACROSS THE CWA...MAINLY THURSDAY NIGHT...RENDERING FRIDAY ALSO A BIT COOLER. NOW...BY COOLER AND DRIER...NOT SPEAKING OF HIGHS IN THE 30S TO LOW 40S. RATHER...HIGH TEMPERATURES WILL LIKELY BE MORE LIKE 50S FOR TUESDAY AND WEDNESDAY /STILL ABOVE NORMAL/...A BIT WARMER FOR THURSDAY...AND THEN LIKELY BACK DOWN INTO THE 50S FOR FRIDAY. PRECIPITATION CHANCES ARE TRENDING DOWNWARD MONDAY NIGHT AND ALL BUT GONE ON TUESDAY...WITH DRY FORECAST CONDITIONS PERSISTING THROUGH THURSDAY. THERE MAY BE ENOUGH LIFT/FORCING AND MOISTURE AROUND THURSDAY NIGHT...ATTACHED TO THE COLD FROPA...TO SEE A FEW SHOWERS DEVELOP...MAINLY OVER NERN SODAK OVER INTO MN. THEN...THE FORECAST TIPS BACK OVER TO A DRY ONE ON FRIDAY. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE STILL EXPECTED AT MBG AND PIR THROUGH TODAY AND TONIGHT. THERE IS SOME POTENTIAL FOR STRATUS EARLY SUNDAY MORNING IN THE WEST...ADVECTING IN ON SE SFC WINDS...BUT STILL TOO UNCERTAIN TO ADD TO THE TAFS. LOW CLOUDS AND FOG WILL BREAK UP AND THEN FILL BACK IN THROUGH THE DAY WITH IFR CIGS LIFTING TO MVFR CIGS...BUT LIKELY NOT DISSIPATING COMPLETELY. LATER TONIGHT AFTER SUNSET...BKN COVERAGE OF LOW CIGS AND/OR FOG IS EXPECTED TO RE- ESTABLISH OVER CENTRAL AND EASTERN SOUTH DAKOTA. WINDS WILL INCREASE ON SUNDAY OUT OF THE SOUTH TO SOUTHEAST. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TO 10 PM CDT /9 PM MDT/ SUNDAY FOR LOWER BAD RIVER-MISSOURI COTEAU-UPPER CHEYENNE-UPPER MISSOURI COTEAU. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR UPPER JAMES RIVER. MN...NONE. && $$ UPDATE...WISE SHORT TERM...TMT LONG TERM...DORN AVIATION...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1125 AM CDT SAT MAR 17 2012 .UPDATE...REST OF TODAY UPDATED FIRE WEATHER WATCH TO RED FLAG WARNING ACROSS CENTRAL SOUTH DAKOTA FOR SUNDAY AFTERNOON. STRATUS CLOUDS ARE QUICKLY FILLING IN AND EXPANDING ACROSS THE EASTERN CWA AS LOW LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD. SEVERAL CHANGES NEEDED TO WEATHER ELEMENTS THIS MORNING TO ACCOUNT FOR THIS. INCREASED SKY COVER QUITE A BIT THROUGH THE MORNING AND INTO THE AFTERNOON. RUC SOUNDINGS ON BUFKIT PICKING UP ON THESE CLOUDS AND WOULD SUGGEST STRATUS STICKING AROUND INTO THE AFTERNOON BEFORE STRATOCU-ING OUT. THIS ALSO THROWS A WRENCH INTO THE TEMP RISE THIS MORNING SO ADJUSTED HOURLY READINGS. DID NOT MESS WITH HIGHS AT THIS TIME SINCE BY MID TO LATE AFTERNOON STILL EXPECTING CLOUDS TO BREAK UP AND TEMPS TO RISE. WILL MONITOR THIS THOUGH. DEWPOINTS RISING THROUGH THE 50S ACROSS THE EASTERN CWA. FOG STILL HANGING AROUND IN SPOTS AS WELL SO EXTENDED MENTION OF THIS FOR A COUPLE MORE HOURS. FARTHER WEST...PLENTY OF SUNSHINE ALL DAY WITH VERY LOW RH VALUES IN THE AFTERNOON LEADING TO HIGH TO VERY HIGH FIRE DANGER. STILL APPEARS WINDS WILL NOT BE STRONG ENOUGH TO WARRANT AND FIRE HEADLINES FOR THIS AFTERNOON. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH MONDAY PRESSURE GRADIENT CONTINUES TO RELAX...WHICH WILL RESULT IN LIGHTER WINDS TODAY...LESS EFFICIENT MIXING...AND HIGHER HUMIDITY. A POCKET OF HIGHER MOISTURE AIR SITS ACROSS THE EAST AND WILL EXPAND WESTWARDS WITH SOUTH/SOUTHEAST WINDS TODAY...SO TEMPERATURES WILL BE SOMEWHAT LESS EXTREME DESPITE SIMILAR TEMPERATURES ALOFT. AS UPPER TROF CONTINUES TO SLOWLY PUSH EAST...WILL SEE LEE CYCLOGENISIS ACROSS WESTERN SOUTH DAKOTA...INCREASING THE GRADIENT OVERNIGHT ALONG WITH WEAK LOW LEVEL JET FORMATION. A TIGHT HUMIDITY GRADIENT WILL CONTINUE ACROSS THE AREA OVERNIGHT AS WELL. AS THE SYSTEM SHIFTS EAST SUNDAY...PRESSURE GRADIENT INTENSIFIES ALONG WITH A 50-60KT H85 JET MAX. HAVE ISSUED A FIRE WEATHER WATCH GIVEN DEEP MIXING WHICH WILL HELP MIX OUT SHALLOW MOISTURE IN THE WEST. THERE IS PLENTY OF UNCERTAINTY OVER HOW EFFICIENTLY THIS MOISTURE WILL MIX OUT IN THE EAST. WINDS WILL STAY UP OVERNIGHT SUNDAY/EARLY MONDAY AS WELL. AS FOR PRECIPITATION CHANCES...WITH WARM LOW LEVEL AIRMASS...WILL SEE STEEP LAPSE RATES ALOFT THROUGH MOST OF THE PERIOD. MOISTURE IS RELATIVELY SHALLOW AND DYNAMICS ARE LACKING FOR MOST OF THE PERIOD TO WARRANT MENTION OF THUNDER...UNTIL LATE SUNDAY. A WEAK WAVE IN SOUTHWEST FLOW COULD SUPPORT HIGH BASED ALTO CUMULUS. MORE WIDESPREAD CONVECTION IS POSSIBLE WITH A STRONGER WAVE LIFTING NORTH WITH A SLOW MOVING NORTH/SOUTH ORIENTED COLD FRONT PROVIDING THE FOCUS FOR THUNDERSTORMS. .LONG TERM...MONDAY NIGHT THROUGH FRIDAY THE THEME DURING THE EXTENDED IS COOL DOWN. MONDAY NIGHT...A COLD FRONT IS WORKING ACROSS THE EASTERN HALF OF FORECAST ZONES...WITH NOTABLY COOLER/DRIER AIR ADVECTING IN BEHIND FOR TUESDAY AND WEDNESDAY. FOLLOWED THE PREFERRED ECMWF SOLUTION FOR HANDLING THE CLOSED UPPER LOW ENERGY OVER THE LOWER/MID-MISSISSIPPI VALLEY REGION...WHICH IS TO PROPAGATE THE LOW EASTWARD AWAY FROM THIS REGION AS THE WEEK WEARS ON...VERSUS THE GFS SOLUTION THAT STILL TRIES TO DRAW THE CLOSED UPPER LOW NORTHWARD TOWARD IOWA. THE ECMWF ACTUALLY DOES TRY TO BRING A BIT OF RETURN FLOW WARMTH BACK INTO THE REGION ON THURSDAY BEFORE A LOW PRESSURE SYSTEM IN THE FAST WESTERLY FLOW ACROSS SOUTHERN CANADA DRAGS A COLD FRONT ACROSS THE CWA...MAINLY THURSDAY NIGHT...RENDERING FRIDAY ALSO A BIT COOLER. NOW...BY COOLER AND DRIER...NOT SPEAKING OF HIGHS IN THE 30S TO LOW 40S. RATHER...HIGH TEMPERATURES WILL LIKELY BE MORE LIKE 50S FOR TUESDAY AND WEDNESDAY /STILL ABOVE NORMAL/...A BIT WARMER FOR THURSDAY...AND THEN LIKELY BACK DOWN INTO THE 50S FOR FRIDAY. PRECIPITATION CHANCES ARE TRENDING DOWNWARD MONDAY NIGHT AND ALL BUT GONE ON TUESDAY...WITH DRY FORECAST CONDITIONS PERSISTING THROUGH THURSDAY. THERE MAY BE ENOUGH LIFT/FORCING AND MOISTURE AROUND THURSDAY NIGHT...ATTACHED TO THE COLD FROPA...TO SEE A FEW SHOWERS DEVELOP...MAINLY OVER NERN SODAK OVER INTO MN. THEN...THE FORECAST TIPS BACK OVER TO A DRY ONE ON FRIDAY. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE STILL EXPECTED AT MBG AND PIR THROUGH TODAY AND TONIGHT. LOW LEVEL MOISTURE HAS BEEN INCREASING EARLY THIS MORNING AND COULD BRING SOME LIGHT FOG AND LOW STRATUS TO PARTS OF NORTHEAST SOUTH DAKOTA THIS MORNING INCLUDING AT ABR AND ATY...BUT ESPECIALLY AT ATY. OTHERWISE...ANY LOW CLOUDS AND FOG WILL BREAK UP THROUGH THE LATE MORNING AND EARLY AFTERNOON WITH IFR CIGS LIFTING TO MVFR CIGS...BUT PROLLY NOT DISSIPATING COMPLETELY. LATER TONIGHT AFTER SUNSET...SCT-BKN COVERAGE OF LOW CIGS AND/OR FOG IS EXPECTED TO RE-ESTABLISH OVER CENTRAL AND EASTERN SOUTH DAKOTA. WILL NEED TO MONITOR AND ADJUST FOG/STRATUS COVERAGE LATER TONIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TO 10 PM CDT /9 PM MDT/ SUNDAY FOR LOWER BAD RIVER-MISSOURI COTEAU-UPPER CHEYENNE-UPPER MISSOURI COTEAU. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR UPPER JAMES RIVER. MN...NONE. && $$ UPDATE...TMT SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1017 AM CDT SAT MAR 17 2012 .UPDATE...REST OF TODAY STRATUS CLOUDS ARE QUICKLY FILLING IN AND EXPANDING ACROSS THE EASTERN CWA AS LOW LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD. SEVERAL CHANGES NEEDED TO WEATHER ELEMENTS THIS MORNING TO ACCOUNT FOR THIS. INCREASED SKY COVER QUITE A BIT THROUGH THE MORNING AND INTO THE AFTERNOON. RUC SOUNDINGS ON BUFKIT PICKING UP ON THESE CLOUDS AND WOULD SUGGEST STRATUS STICKING AROUND INTO EARLY AFTERNOON BEFORE STRATOCU-ING OUT. THIS ALSO THROWS A WRENCH INTO THE TEMP RISE THIS MORNING SO ADJUSTED HOURLY READINGS. DID NOT MESS WITH HIGHS AT THIS TIME SINCE BY MID TO LATE AFTERNOON STILL EXPECTING CLOUDS TO BREAK UP AND TEMPS TO RISE. WILL MONITOR THIS THOUGH. DEWPOINTS RISING THROUGH THE 50S ACROSS THE EASTERN CWA. FOG STILL HANGING AROUND IN SPOTS AS WELL SO EXTENDED MENTION OF THIS FOR A COUPLE MORE HOURS. FARTHER WEST...PLENTY OF SUNSHINE ALL DAY WITH VERY LOW RH VALUES IN THE AFTERNOON LEADING TO HIGH TO VERY HIGH FIRE DANGER. STILL APPEARS WINDS WILL NOT BE STRONG ENOUGH TO WARRANT ANY FIRE HEADLINES FOR THIS AFTERNOON. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH MONDAY PRESSURE GRADIENT CONTINUES TO RELAX...WHICH WILL RESULT IN LIGHTER WINDS TODAY...LESS EFFICIENT MIXING...AND HIGHER HUMIDITY. A POCKET OF HIGHER MOISTURE AIR SITS ACROSS THE EAST AND WILL EXPAND WESTWARDS WITH SOUTH/SOUTHEAST WINDS TODAY...SO TEMPERATURES WILL BE SOMEWHAT LESS EXTREME DESPITE SIMILAR TEMPERATURES ALOFT. AS UPPER TROF CONTINUES TO SLOWLY PUSH EAST...WILL SEE LEE CYCLOGENISIS ACROSS WESTERN SOUTH DAKOTA...INCREASING THE GRADIENT OVERNIGHT ALONG WITH WEAK LOW LEVEL JET FORMATION. A TIGHT HUMIDITY GRADIENT WILL CONTINUE ACROSS THE AREA OVERNIGHT AS WELL. AS THE SYSTEM SHIFTS EAST SUNDAY...PRESSURE GRADIENT INTENSIFIES ALONG WITH A 50-60KT H85 JET MAX. HAVE ISSUED A FIRE WEATHER WATCH GIVEN DEEP MIXING WHICH WILL HELP MIX OUT SHALLOW MOISTURE IN THE WEST. THERE IS PLENTY OF UNCERTAINTY OVER HOW EFFICIENTLY THIS MOISTURE WILL MIX OUT IN THE EAST. WINDS WILL STAY UP OVERNIGHT SUNDAY/EARLY MONDAY AS WELL. AS FOR PRECIPITATION CHANCES...WITH WARM LOW LEVEL AIRMASS...WILL SEE STEEP LAPSE RATES ALOFT THROUGH MOST OF THE PERIOD. MOISTURE IS RELATIVELY SHALLOW AND DYNAMICS ARE LACKING FOR MOST OF THE PERIOD TO WARRANT MENTION OF THUNDER...UNTIL LATE SUNDAY. A WEAK WAVE IN SOUTHWEST FLOW COULD SUPPORT HIGH BASED ALTO CUMULUS. MORE WIDESPREAD CONVECTION IS POSSIBLE WITH A STRONGER WAVE LIFTING NORTH WITH A SLOW MOVING NORTH/SOUTH ORIENTED COLD FRONT PROVIDING THE FOCUS FOR THUNDERSTORMS. .LONG TERM...MONDAY NIGHT THROUGH FRIDAY THE THEME DURING THE EXTENDED IS COOL DOWN. MONDAY NIGHT...A COLD FRONT IS WORKING ACROSS THE EASTERN HALF OF FORECAST ZONES...WITH NOTABLY COOLER/DRIER AIR ADVECTING IN BEHIND FOR TUESDAY AND WEDNESDAY. FOLLOWED THE PREFERRED ECMWF SOLUTION FOR HANDLING THE CLOSED UPPER LOW ENERGY OVER THE LOWER/MID-MISSISSIPPI VALLEY REGION...WHICH IS TO PROPAGATE THE LOW EASTWARD AWAY FROM THIS REGION AS THE WEEK WEARS ON...VERSUS THE GFS SOLUTION THAT STILL TRIES TO DRAW THE CLOSED UPPER LOW NORTHWARD TOWARD IOWA. THE ECMWF ACTUALLY DOES TRY TO BRING A BIT OF RETURN FLOW WARMTH BACK INTO THE REGION ON THURSDAY BEFORE A LOW PRESSURE SYSTEM IN THE FAST WESTERLY FLOW ACROSS SOUTHERN CANADA DRAGS A COLD FRONT ACROSS THE CWA...MAINLY THURSDAY NIGHT...RENDERING FRIDAY ALSO A BIT COOLER. NOW...BY COOLER AND DRIER...NOT SPEAKING OF HIGHS IN THE 30S TO LOW 40S. RATHER...HIGH TEMPERATURES WILL LIKELY BE MORE LIKE 50S FOR TUESDAY AND WEDNESDAY /STILL ABOVE NORMAL/...A BIT WARMER FOR THURSDAY...AND THEN LIKELY BACK DOWN INTO THE 50S FOR FRIDAY. PRECIPITATION CHANCES ARE TRENDING DOWNWARD MONDAY NIGHT AND ALL BUT GONE ON TUESDAY...WITH DRY FORECAST CONDITIONS PERSISTING THROUGH THURSDAY. THERE MAY BE ENOUGH LIFT/FORCING AND MOISTURE AROUND THURSDAY NIGHT...ATTACHED TO THE COLD FROPA...TO SEE A FEW SHOWERS DEVELOP...MAINLY OVER NERN SODAK OVER INTO MN. THEN...THE FORECAST TIPS BACK OVER TO A DRY ONE ON FRIDAY. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE STILL EXPECTED AT MBG AND PIR THROUGH TODAY AND TONIGHT. LOW LEVEL MOISTURE HAS BEEN INCREASING EARLY THIS MORNING AND COULD BRING SOME LIGHT FOG AND LOW STRATUS TO PARTS OF NORTHEAST SOUTH DAKOTA THIS MORNING INCLUDING AT ABR AND ATY...BUT ESPECIALLY AT ATY. OTHERWISE...ANY LOW CLOUDS AND FOG WILL BREAK UP THROUGH THE LATE MORNING AND EARLY AFTERNOON WITH IFR CIGS LIFTING TO MVFR CIGS...BUT PROLLY NOT DISSIPATING COMPLETELY. LATER TONIGHT AFTER SUNSET...SCT-BKN COVERAGE OF LOW CIGS AND/OR FOG IS EXPECTED TO RE-ESTABLISH OVER CENTRAL AND EASTERN SOUTH DAKOTA. WILL NEED TO MONITOR AND ADJUST FOG/STRATUS COVERAGE LATER TONIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR LOWER BAD RIVER-MISSOURI COTEAU-UPPER CHEYENNE-UPPER JAMES RIVER-UPPER MISSOURI COTEAU. MN...NONE. && $$ UPDATE...TMT SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1143 PM CDT FRI MAR 16 2012 .UPDATE... HAVE UPDATED GRIDS REDUCING POPS AND ADDING MENTION OF AREAS OF FOG PRIMARILY WEST OF A CHILDRESS TO POST LINE AS MOIST AIR STREAMS INTO THE REGION ONCE AGAIN. IT IS POSSIBLE THAT IF THE WINDS CONTINUE TO DIMINISH AS IS EVIDENT ACROSS THE SOUTHEAST......PARTICULARLY ACROSS THE LLANO ESTACADO...DENSE FOG WILL BE POSSIBLE. && .AVIATION... FOG WILL BE PRIMARY CONCERN AND IFR TO LIFR CONDITIONS ARE CERTAINLY POSSIBLE AT BOTH SITES THIS MORNING. LOW LEVEL MOISTURE CONTINUES TO STREAM IN UNDER CLEARING SKIES. IF DECOUPLING OF LLJ CAN INCREASE WITH THE NEAR-SURFACE INVERSION SETTING UP...CONDITIONS COULD DETERIORATE RAPIDLY. && PREV DISCUSSION... /ISSUED 358 PM CDT FRI MAR 16 2012/ SHORT TERM... THE FORECAST AND SEVERE WEATHER PARAMETERS ARE PROGRESSING AS EXPECTED FROM THIS MORNINGS UPDATE. LATEST RUC ANALYSIS INDICATES 3500 J/KG OF SURFACE INSTABILITY NOSING INTO THE AREA WITH AREAS OF HIGH THETA-E AIR AND NO SURFACE BASED CIN. DEEP LAYER SHEAR CONTINUES TO INCREASE OVER THE AREA WITH ABOUT 30KT OBSERVED. ADDITIONALLY...A LARGE AREA OF ACCAS HAS BEEN OBSERVED SOUTH AND SOUTHWEST OF THE LUBBOCK AREA. WILL CONTINUE TO EXPECT AN INITIATION TIME AFTER 21Z. THE PRIMARY SEVERE THREAT REMAINS AS LARGE HAIL AND DAMAGING WINDS. DESPITE SUPERCELLULAR STRUCTURE EXPECTED WITH STORMS...TORNADOES ARE NOT AS LIKELY DUE TO THE VERY WEAK LOW LEVEL SHEAR. FOG IS AGAIN EXPECTED TONIGHT AND COULD BECOME DENSE AGAIN ON THE CAPROCK. THE DRYLINE IS EXPECTED TO MIX FURTHER EAST SATURDAY AFTERNOON. THE CAP IS PROGGED TO BE NEARLY ZERO OFF THE CAPROCK WITH VERY STRONG SURFACED BASED CAPE IN EXCESS OF 3 KJ/KG. HOWEVER...THERE WILL BE A LACK OF LARGE SCALE LIFT TOMORROW AFTERNOON WITH ONLY WEAK LOW LEVEL CONVERGENCE ALONG THE DRYLINE. WILL KEEP THE SLIGHT CHANCE GOING FOR SATURDAY AFTERNOON GIVEN THESE PARAMETERS IN PLACE. JDV LONG TERM... ANOTHER WEAK DISTURBANCE LOOKS TO MOVE OVER THE AREA SATURDAY NIGHT INTO EARLY SUNDAY MORNING BUT POINT SOUNDINGS SHOW A PRETTY STRONG CAP IN PLACE THAT MAY LIMIT STORM CHANCES SOMEWHAT. CHANCES FOR STORMS...A FEW ONCE AGAIN POSSIBLY SEVERE...LOOKS TO BE BETTER SUNDAY NIGHT INTO MONDAY MORNING AS A COMBINATION OF THE APPROACH OF THE MAIN LOW...INCREASING DEEP LAYER SHEAR AND CURVED LOW-LEVEL HODOGRAPH...AND INCREASING MOISTURE IN THE LOWER ATMOSPHERE THANKS TO A LOW-LEVEL JET ALL CONTRIBUTE TO DECENT INSTABILITY LEVELS. DID INCREASE POPS FOR SUNDAY NIGHT THROUGH MONDAY MORNING AS THE DRYLINE/PACIFIC FRONT HELPS TO FOCUS SURFACE CONVERGENCE AND THEN CLEAR PRECIPITATION OUT FROM WEST TO EAST THROUGH THE MORNING. OTHER CONCERN WITH THE SYSTEM AS IT MOVES OUT ACROSS THE AREA WILL BE FIRE WEATHER FOR MONDAY. SEE FIRE WEATHER DISCUSSION SECTION FOR MORE DETAILS. DRY AIR WILL RAPIDLY SWEEP IN ON A BREEZY TO WINDY WESTERLY WIND DURING THE DAY MONDAY. MODELS HAVE COME INTO BETTER AGREEMENT ON DEVELOPING THE TROF INTO A CLOSED LOW AND TAKING IT FURTHER EAST RATHER THAN PREVIOUS RUNS KEEPING IT CLOSER TO THE FORECAST AREA. FORECAST PARAMETERS WILL DEPEND ON WHETHER WE WILL HAVE WEAK SHORTWAVE RIDGING OR ZONAL FLOW ACROSS THE AREA. DRY AIR WILL SLOWLY MODIFY AT THE SURFACE THROUGH THE END OF NEXT WEEK WHICH WILL KEEP THE FORECAST DRY. HOWEVER...FOCUS IS ON SEVERE WEATHER POTENTIAL FOR THE NEXT SEVERAL DAYS SO MOST OF THE EXTENDED FORECAST WAS NOT CHANGED. JORDAN FIRE WEATHER... ELEVATED TO LOW END CRITICAL FIRE WEATHER CONDITIONS WILL BE LIKELY SATURDAY AFTERNOON ACROSS THE WESTERN SOUTH PLAINS. A SURFACE TROUGH WILL STRENGTHEN SATURDAY AFTERNOON LEADING TO GUSTY SOUTHWEST WINDS ON THE WEST SIDE OF A DRYLINE. THIS DRYLINE WILL MOVE TO THE EDGE OF THE CAPROCK TOMORROW AFTERNOON WITH VERY DRY AIR TO THE WEST OF THIS FEATURE. GUSTY WINDS COMBINED WITH VERY WARM TEMPERATURES WILL LEAD TO THE ELEVATED OR LOW END CRITICAL FIRE WEATHER CONDITIONS. ANOTHER MORE WIDESPREAD FIRE WEATHER EVENT WILL BE POSSIBLE ON SUNDAY AS STRONG WESTERLY WINDS AND DRY AIR PUSH INTO THE REGION BEHIND A DEPARTING STORM SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 46 84 52 81 46 / 0 0 0 20 30 TULIA 53 83 58 80 49 / 10 10 20 30 40 PLAINVIEW 51 82 58 81 50 / 10 10 20 30 50 LEVELLAND 51 82 59 82 50 / 0 10 10 30 40 LUBBOCK 54 83 60 81 53 / 10 10 20 30 50 DENVER CITY 52 82 56 84 50 / 0 10 10 20 40 BROWNFIELD 53 83 60 83 51 / 0 10 20 30 40 CHILDRESS 57 84 62 80 60 / 10 20 20 30 60 SPUR 55 83 61 80 58 / 10 20 20 30 50 ASPERMONT 59 80 64 79 59 / 10 20 20 30 50 && .LUB WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR THE FOLLOWING ZONES: TXZ021>023-027-028-033-034-039-040. && $$ 99/99/26
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
129 AM EDT SAT MAR 17 2012 .SYNOPSIS... HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL MAINTAIN A MOIST SOUTHWEST FLOW OF AIR ACROSS THE REGION. WEAK UPPER LEVEL IMPULSES WILL PASS FROM THE OHIO VALLEY ACROSS THE MID ATLANTIC REGION HELPING TO TRIGGER SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL MOVE SOUTH THROUGH THE MID ATLANTIC STATES TONIGHT AND SATURDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 931 PM EDT FRIDAY... SHOWERS ARE JUST ABOUT OUT OF THE NW PIEDMONT OF NC. ANOTHER AREA OF SHRA/TSRA MOVING ACROSS E TN INTO WRN NC JUST SOUTH OF THE NC MTNS. LATEST HRRR AND LOCAL WRF TAKE THIS BATCH OF SHOWERS INTO THE MTNS OF NC AND FOOTHILLS THROUGH EARLY OVERNIGHT. WEAKENING TREND WITH LOSS OF HEATING WILL LEAD TO ONLY ISOLATED TSRA. WILL KEEP HIGHER POPS IN THE SOUTH...WITH LESS TO NONE IN THE NRN CWA. FOG WILL ALSO FORM TONIGHT AS THE GROUND/LOW LVLS STAY MOIST. BACKDOOR FRONT OVER NRN/ERN VA WILL SLIDE SW TOWARD THE AREA BY EARLY MORNING...ALTHOUGH MODELS KEEP STABLE LAYER ACROSS THE PIEDMONT NE OF LYH THROUGH DAWN. EXPECT TO SEE TEMPS DROP TOWARD THE UPPER 40S IN THE NW/N AND ALONG THE MTNS OF NC LATE...WITH 50S ELSEWHERE. TEMPERATURES TRICKY FOR TOMORROW. EASTERLY FLOW SHOULD KEEP TEMPERATURES ALONG AND EAST OF THE BLUE RIDGE COOL AND BELOW GUIDANCE. THAT IS...IF THE AREA CAN MAINTAIN CLOUD COVER. DEW POINTS BEHIND THE BOUNDARY ARE STILL MUGGY AND IN THE UPPER 40S TO MID 50S. THEREFORE...IT LOOKS AS IF THE CLOUDS WILL REMAIN THROUGH MOST OF TOMORROW. THE UPPER LEVEL TROUGH AND ASSOCIATED SHORT WAVES SHOULD ALSO HELP MAINTAIN CLOUD COVER AND PROVIDE RAIN IN THE AFTERNOON. DID WARM TEMPERATURES UP FROM PREVIOUS FORECAST BUT KEPT IT COOLER THAN GUIDANCE ALONG AND EAST OF THE BLUE RIDGE. DOWNSLOPING FLOW WILL HELP THE WESTERN SLOPES WARM ABOVE NORMAL...ESPECIALLY AS RAIN PULLS OUT BY AFTERNOON. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 310 PM EDT FRIDAY... FORECAST WILL BE DOMINATED BY SUB-SYNOPTIC SCALE PHENOMENA SUNDAY-MONDAY AS SEVERAL SHORT-WAVES TRANSIT THROUGH THE BROAD UPPER RIDGE LOCATED OVER THE EASTERN STATES. EXPECT THIS ENERGY TO INTERACT WITH A MOIST AND FAIRLY UNSTABLE AIR MASS TO BRING CHANCES FOR SHOWERS AND A FEW THUNDERSTORMS THROUGH MUCH OF THE PERIOD. WENT MAINLY WITH DIURNAL/TERRAIN DRIVEN POP TRENDS WITH HIGHEST IN THE MOUNTAINS AND IN THE AFTERNOON. TEMPS WILL REMAIN VERY WARM AS HEIGHTS/THICKNESSES CONTINUE IN THE LATE SPRING/EARLY SUMMER PATTERN THAT HAS BROUGHT WIDESPREAD RECORD WARMTH TO MUCH OF THE EASTERN CONUS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 250 PM EDT THURSDAY... EXTENDED FORECAST IS LITTLE CHANGED IN THE OVERALL SYNOPTIC PATTERN WITH THE DEEP WESTERN TROUGH AND STRONG UPPER RIDGE STILL DOMINANT OVER THE CONUS. THE TENDENCY IS FOR THE TROUGH TO EDGE EASTWARD AS THE WEEK PROGRESSES. GFS ENSEMBLES SHOW VERY LITTLE SPREAD IN THE H5 HEIGHT FIELD INTO WEDNESDAY WITH INCREASING SPREAD AMONG THE MEMBERS AS NORTHERN STREAM ENERGY EVENTUALLY BEGINS TO CARVE OUT A CLOSED LOW OVER THE WESTERN PLAINS BY LATE WED/THU WHICH IS THEN EJECTED SLOWLY EASTWARD REACHING THE OH VALLEY BY AROUND FRIDAY DEPENDING ON YOUR MODEL OF CHOICE. THE MID-WEEK PERIOD WILL BE CHARACTERIZED BY A SCATTERED DIURNAL SHOWER REGIME DRIVEN BY WEAK SHORT-WAVES AND PROBABLE OUTFLOW BOUNDARIES. AGAIN DIFFICULT TO PINPOINT COHERENT SPATIAL/TEMPORAL COVERAGE PATTERN OTHER THAN HIGHER LIKELIHOOD OF TYPICAL MOUNTAIN AND AFTERNOON TO EARLY EVENING ENHANCEMENT OF POPS. INCREASING DEEP LAYER SOUTHERLY FLOW AHEAD OF THE ADVANCING UPPER LOW SYSTEM WILL BRING INCREASED CHANCES FOR MORE ORGANIZED PRECIPITATION LATE IN THE WEEK. TEMPS REMAINING IN THE WELL ABOVE NORMAL (FOR MID-MARCH) RANGE THROUGHOUT THE WEEK RUNNING AT LEAST 10 TO 15F OVER SEASONAL NORMS. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 115 AM EST SATURDAY... STILL SEEING ISOLATED -SHRA IN SPOTS OVER THE SOUTH AND WEST BUT MAINLY STILL VFR WITH MOSTLY MID DECK AROUND. HOWEVER WITH A HIGH LEVEL OF MOISTURE ON THE GROUND...AND SOME CLEARING ALONG WITH A BACK DOOR FRONT ARRIVING LATE...MAY SEE SOME FOG DEVELOPMENT AS WELL AS LOW STRATUS. THIS IS THE MAIN AVIATION ISSUE INTO SAT MORNING...AND FORECAST CONFIDENCE IS MODERATE ON WHICH WILL BE MORE IMPACTED. ATTM...WILL LEAN TOWARD MORE FOG AS THINK ENOUGH CLOUD COVER FROM AC/CS WILL KEEP STRATUS FROM FORMING BUT DID BEEF UP FOG MENTION AT KDAN OVERNIGHT. THE FOG STABILITY OFF THE SOUNDINGS SUGGEST BETTER FOG THREAT. WITH THIS IN MIND WILL HAVE ROA/LYH/DAN DROP TO MVFR VSBYS FROM 08Z UNTIL 13Z. LYH COULD SEE SOME STRATUS...BUT NOT ENOUGH CONFIDENCE FOR ADDING IT. IN THE MTNS THINK BLF/LWB/BCB WILL SEE BETTER FOG THREAT ALTHOUGH SOME MORE CLOUDINESS ARRIVING LATE COULD SEND VSBYS BACK UP AROUND 10-12Z. FOR NOW WILL BE BRING CIGS DOWN TO IFR OR LOWER AT BLF/LWB WITH SCT LOWER CLOUDS IN BCB. VSBYS WILL DROP TO 1 TO 4SM. THE FOG/LOWER CLOUDS WILL BE ERODING BY MID MORNING WITH THE FLOW VARYING FROM NE IN THE LYH AREA TO SOUTH IN THE FAR WEST. ANOTHER SHORTWAVE MOVES ACROSS SATURDAY INTERACTING WITH SFC BOUNDARY TO SPARK ANOTHER ROUND OF SHOWERS/TSRA. ATTM...THE FAVORED AREAS WILL BE SOUTH OF A LWB-ROA-DAN LINE...AND WILL ADD SHRA OR VCSH/CB INTO BLF/BCB AND PERAHPS KROA FOR NOW. WILL SEE VFR CONDITIONS AFTER LATE MORNING AT ALL SITES. AN EASTERLY FLOW LOOKS TO PERSIST INTO SUNDAY. THIS MAY BRING SUB- VFR CONDITIONS TO THE AREA IF THE AIR MASS IS ABLE TO BECOME SATURATED IN THE BOUNDARY LAYER FROM EASTERLY UPSLOPE FLOW. SCATTERED AFTERNOON SHOWERS AND STORMS MAY ALSO OCCUR ESPCLY ALONG/WEST OF THE BLUE RIDGE WITH MVFR OR WORSE CONDITIONS NEAR ANY CONVECTION. STRONG HIGH PRESSURE WILL BUILD ACROSS THE REGION EARLY NEXT WEEK RESULTING IN WIDESPREAD VFR OUTSIDE OF ISOLATED MAINLY AFTERNOON MOUNTAIN SHOWERS MONDAY THRU WEDNESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...RCS/WP NEAR TERM...RCS/WP SHORT TERM...PC LONG TERM...PC AVIATION...JH/RCS/WP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
324 PM CDT SAT MAR 17 2012 .SHORT TERM...TONIGHT AND SUNDAY...FORECAST CONFIDENCE MEDIUM MAIN STORY CONTINUES TO BE THE UNSEASONABLE HEAT ACROSS SOUTHERN WI. THE WARM PUMP JUST KEEPS ON PUMPING WITH MORE RECORD WARMTH ON TAP FOR SUNDAY. RECORD HIGH MINIMUMS WILL BE SHATTERED TONIGHT WITH MORE RECORDS SHATTERED ON SUNDAY. ON THE PRECIP END OF THINGS...PER WATER VAPOR RUC COMBO...WATCHING A COUPLE OF WAVES RIDING NORTHEAST FROM MISSOURI. APPEARS TO BE A DOUBLE VORT STRUCTURE WITH ONE VORT IN SC MO AND THE OTHER IN THE NW. THIS MORE NW VORT IS OF GREATEST CONCERN AS IT HAS THE POTENTIAL TO REPEAT THE CONVECTION IN A SIMILAR FASHION TO WHAT TRANSPIRED SATURDAY MORNING. SEEING EVIDENCE OF SOME INCREASED 850 MOISTURE ADVECTION AROUND 12Z SUNDAY WITH DEW POINTS INCREASING A BIT ON THE EASTERN EDGE OF THE 850 LOW LEVEL JET AXIS. WEAK 700 WARM ADVECTION NOTED WITH SOME FRONTOGENETICAL FORCING. PER MODELS...BELIEVE GREATER COVERAGE AND POTENTIAL WILL BE TO OUR SOUTH WITH THE STRONGER SOUTHERN VORT. ONCE ANY OF THIS CONVECTION GETS OUT OF THE WAY...SHAPING UP TO BE ANOTHER WARM DAY. 925 TEMPS SUPPORT TEMPS SIMILAR TO SATURDAY WITH A FEW READINGS EXCEEDING 80 DEGREES. SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM UPPER RIDGING WILL BE OCCURRING FROM SUN AFT INTO SUN NT AS STRONG LOW PRESSURE AND THE UPPER WAVE OVER THE NRN HIGH PLAINS LIFTS NWD INTO CANADA. MEANWHILE THE SRN PORTION OF THE LARGE UPPER TROUGH OVER THE WEST WILL SLOWLY PROGRESS INTO THE SRN HIGH PLAINS AND TX INTO TUE. THE WARM CONVEYOR BELT AHEAD OF THE UPPER TROUGH WILL EXTEND WELL NWD WITH THE ERN PERIPHERY AFFECTING THE WEST HALF OF WI FOR MON-TUE. THE WEAKENING COLD FRONT OVER THE PLAINS WILL STAY TO THE WEST DURING THIS PERIOD. THUS POPS INCREASE FROM EAST TO WEST ACROSS THE CWA WITH BEST CHANCES FOR PCPN ON MON. THE WARM CONVEYOR BELT MAY ACTUALLY SHIFT SLIGHTLY WWD FOR MON NT AND TUE SO LESSER POPS ARE FORECAST. KEPT TEMPS A LITTLE COOLER FOR MON DUE TO MORE CLOUDS AND PCPN CHANCES BUT INCREASED THEM AGAIN FOR TUE WITH LESS CLOUDS/PCPN CHANCES. .LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM THE LARGE CLOSED LOW OVER TX FOR TUE/TUE NT IS THEN DEPICTED BY THE EXTENDED MODELS TO SLOWLY EJECT NEWD...REACHING THE OHIO RIVER VALLEY BY FRI AND THE EAST COAST LATER ON SAT. THE WEAK COLD FRONT WILL SLOWLY PROGRESS ACROSS SRN WI WED-THU WITH THE WARM CONVEYOR BELT OVERHEAD. DECENT CHANCES OF SHOWERS AND TSTORMS IS FORECAST WITH PCPN CHANCES DECREASING FOR THE END OF THE WEEK AS THE SYSTEM MOVES AWAY. A CANADIAN COLD FRONT WILL THEN ARRIVE FRI NT IN RESPONSE TO CYCLOGENESIS MOVING EWD ACROSS SRN CANADA. SOME DIFFERENCES ON MODELS ON THE STRENGTH OF THE COOL AIR BUT BEST ESTIMATE AT THIS TIME IS FOR HIGHS IN THE 50S ON SAT WHICH IS STILL ABOVE NORMAL. && .AVIATION/00Z TAFS/...VFR THIS PERIOD WITH BROAD SOUTHERLY FLOW CONTINUING BETWEEN HIGH PRESSURE ON THE EAST COAST AND LOW PRESSURE SITUATED OVER THE NORTHERN PLAINS. CU FIELD WILL DISSIPATE WITH THE LOSS OF DAYTIME HEATING. LIGHT FOG POTENTIAL LATER TONIGHT AND EARLY SUNDAY BUT WILL NOT LATCH ONTO THE DENSE FOG PLAYED OUT BY MOS WITH MAIN SYNOPTIC WARM FRONT WELL NORTH. POPS ARE IN THE SINGLE DIGITS. WILL HAVE TO WATCH ANOTHER WAVE PROGGD TO TRACK SOUTH OF WI LATER TONIGHT AND SUNDAY MORNING. GFS MORE GENEROUS WITH QPF BUT GUID POPS ARE QUITE LOW. IF STORMS DEVELOP EXPECTING COVERAGE TO BE ISOLATED AT BEST...WILL LEAVE OUT MENTION FOR NOW UNTIL CONVECTIVE TRENDS IN TERMS OF TIMING AND COVERAGE BECOME MORE CLEAR. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1231 PM CDT SAT MAR 17 2012 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 310 AM CDT SAT MAR 17 2012 MAIN FORECAST CONCERNS ARE ON ANY CHANCES FOR PRECIPITATION THROUGH SUNDAY NIGHT...WINDS AND THE UNPRECEDENTED WARMTH. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING JUST OFF THE CALIFORNIA COAST WHILE BROAD RIDGING WAS BUILDING DOWNSTREAM OVER THE EASTERN TWO THIRDS OF THE U.S.. RIDGE AXIS SITS OVER THE GREAT LAKES...PLACING THE FORECAST AREA UNDER SOUTHWEST FLOW. WITHIN THIS SOUTHWEST FLOW...A WEAK SHORTWAVE COMBINED WITH A WARM FRONTAL BOUNDARY AND INCREASING LOW LEVEL JET TO PRODUCE A CLUSTER OF STRONG TO SEVERE SHOWERS AND THUNDERSTORMS LAST EVENING OVER CENTRAL WISCONSIN. THESE HAVE SINCE LIFTED INTO UPPER MICHIGAN THANKS TO THE SHORTWAVE MOVING NORTHEAST AND A 30-40 KT SOUTHWEST JET AT 850MB. WITHIN THIS SOUTHWEST FLOW...THE ONLY SHORTWAVES OF NOTE ARE WEAK ONES IN NEBRASKA...AND THESE ARE NOT PRODUCING MUCH CLOUDS AT ALL. WITH THE FORECAST AREA UNDER THAT STRONG SOUTHWEST JET AND A RELATIVELY TIGHT PRESSURE GRADIENT AT THE SURFACE AHEAD OF A TROUGH IN THE DAKOTAS... TEMPERATURES HAVE STRUGGLED TO FALL. READINGS ARE ONLY IN THE 60S. DEWPOINTS ARE ALSO STAYING UP IN THE MID TO UPPER 50S. AIRMASS IS ALSO SEMI-CAPPED AND DRY...LOOKING AT THE 00Z DVN SOUNDING. GOING FARTHER SOUTHWEST TO OAX AND IT DRIES OUT EVEN MORE. DESPITE THE DRIER AIR...THERE IS ENOUGH INSTABILITY WHEN LIFTED FROM 800MB /APPROX 700 J/KG/ TO PRODUCE PRECIPITATION. A ZONE OF 800MB SPEED CONVERGENCE IN SOUTHWEST WISCONSIN AND NORTHWEST ILLINOIS HAS PRODUCED SOME SHOWERS DOWN THERE. TODAY THROUGH SUNDAY NIGHT...UPPER TROUGHING APPROACHING THE WEST COAST OF THE U.S. RIGHT NOW IS PROGGED BY ALL MODELS TO MOVE INTO THE ROCKIES BY 12Z MONDAY. A FAIRLY DEEP LOW PRESSURE SYSTEM ENDS UP DEVELOPING OVER EASTERN MONTANA AS THIS TROUGH MOVES EAST...ALLOWING FOR STRONG SOUTHERLY FLOW TO PERSIST DOWNSTREAM INTO OUR FORECAST AREA. A COUPLE OF IMPACTS FROM THIS STRONG SOUTHERLY FLOW INCLUDE: 1. HELPING TO MAINTAIN THE UNSEASONABLY HIGH DEWPOINTS...WHICH COULD EXCEED 60F AT TIMES BETWEEN 15-18Z BEFORE DROPPING DUE TO MIXING. 2. MAINTAIN THE UNSEASONABLY WARM 925 AND 850MB TEMPS...WHICH ARE PROGGED TO STAY BETWEEN 16-20C AND 12-14C RESPECTIVELY. THESE READINGS ARE VERY SIMILAR TO WHAT WAS SEEN FRIDAY...SO HIGH TEMPERATURES BOTH TODAY AND SUNDAY ARE LIKELY TO BE SIMILAR. SOME HINTS FROM MET GUIDANCE WHICH DID WELL YESTERDAY THAT SITES SUCH AS BOSCOBEL COULD HIT THE MID 80S. GENERALLY FOLLOWED THIS. 3. A LOT OF GUSTY WINDS THROUGHOUT. APPEARS THAT WHEN LOOKING AT SOUNDINGS...MIXING DEPTHS AT MOST APPROACH 850MB. MOMENTUM TRANSFER FROM THIS LEVEL KEEPS WINDS BELOW ADVISORY CRITERIA...EVEN AT RST. 4. RESULTING FROM ITEMS 1-3 ABOVE...LOW TEMPERATURES ARE GOING TO STAY VERY WARM FOR THIS TIME OF YEAR...LIKELY STRUGGLING TO GET MUCH BELOW 60. REGARDING PRECIPITATION...TRIGGERS ARE VERY HARD TO FIND THROUGH SUNDAY NIGHT. IN ADDITION...THE AIRMASS LOOKS A LITTLE MORE CAPPED PER RUC/GFS SOUNDINGS. WE DO HAVE THE WEAK SHORTWAVES IN NEBRASKA COMING ACROSS THE FORECAST AREA AT 18Z TODAY...BUT THERE IS NO SURFACE CONVERGENT FEATURE LIKE YESTERDAY WITH THE WARM FRONT. IN FACT...NO SURFACE CONVERGENT FEATURES ARE PRESENT THROUGH SUNDAY NIGHT. AFTER 06Z SUNDAY NIGHT...THERE ARE INDICATIONS OF A SHORTWAVE COMING ACROSS SOUTHEAST MINNESOTA...AS WELL AS ISENTROPIC LIFT ON THE 305-310 K SURFACES. THE 17.00Z GFS/CANADIAN BOTH HINT AT POTENTIAL FOR SOME CONVECTION IN THIS AREA...SO INCLUDED SOME 20 PERCENT CHANCES FOR NOW...GIVEN NAM/UKMET/ECMWF DRY. FOR THE REST OF THE PERIOD...ALL MODELS ARE PRETTY MUCH DRY THROUGH SUNDAY WHICH SEEMS REASONABLE. MONDAY AND MONDAY NIGHT...THE UPPER TROUGHING OVER THE ROCKIES IS FORECAST TO INCH EASTWARD...WITH ITS AXIS FROM EASTERN MONTANA INTO NEW MEXICO AT 12Z TUESDAY. ALTHOUGH THIS TROUGH IS FAR AWAY FROM THE AREA...WE WILL SEE 10-30 METER 500MB HEIGHT FALLS EACH 12 HOUR PERIOD OVER THE FORECAST AREA...HIGHEST WEST. THESE HEIGHT FALLS COMBINED WITH STRONG MOISTURE TRANSPORT ON A SOUTHERLY 40-60 KT 850MB JET WILL YIELD INCREASING PRECIPITATION CHANCES...ESPECIALLY AGAIN OVER THE WEST. PRECIPITABLE WATER VALUES CLIMB TO 1-1.4 INCHES WHICH WOULD SUPPORT SOME DECENT PRECIPITATION TOO. CAPE VALUES ARE RESTRICTED SOMEWHAT DUE TO CLOUD COVER...PERHAPS UP TO 500 J/KG OF VERY THIN MUCAPE. THIS SHOULD LIMIT THUNDER COVERAGE TOO. DESPITE THE INCREASED CLOUD COVER AND PRECIPITATION...STILL ANTICIPATING TEMPERATURES TO RISE INTO THE 70S ON MONDAY...WARMEST EAST WHERE SOME SUN COULD OCCUR. LOWS STAY UP TOO MONDAY NIGHT WITH THE SURFACE COLD FRONT STILL WAY OFF TO THE WEST IN THE EASTERN DAKOTAS. .LONG TERM...TUESDAY THROUGH FRIDAY NIGHT 310 AM CDT SAT MAR 17 2012 LONG TERM FORECAST IS BECOMING MORE UNCERTAIN...PRIMARILY BECAUSE MODELS ARE STRUGGLING ON HOW TO HANDLE THE WESTERN U.S. TROUGH FROM MONDAY NIGHT. 17.00Z ECMWF/GFS/CANADIAN AND MOST GFS ENSEMBLES ALL SUGGEST THE TROUGH WILL CUT-OFF AS IT CROSSES THE PLAINS TUESDAY AND WEDNESDAY...BUT EXACTLY WHEN AND THEN HOW TO HANDLE THIS UPPER LOW VARIES AMONG EVERY MODEL. THERE STILL REMAINS A FEW GFS ENSEMBLES AND THE 17.00Z UKMET THAT SUGGEST THE TROUGH STAYS TOGETHER... FOLLOWING THE 16.12Z ECMWF IDEA. HOWEVER...OVER THE LAST COUPLE DAYS OF MODEL RUNS...THESE SEEM TO BE AN OUTLIER. THEREFORE PREFERENCE IS TO FOLLOW THE MAJORITY 17.00Z GUIDANCE. AS THE UPPER TROUGH APPROACHES THE FORECAST AREA TUESDAY INTO WEDNESDAY...THE MOISTURE STREAM REFERENCED IN THE MONDAY/MONDAY NIGHT DISCUSSION WILL FULLY SHIFT OVERHEAD. SEEMS LIKE TUESDAY NIGHT IS THE BEST PERIOD FOR THE ENTIRE FORECAST AREA TO SEE RAIN. MODEL GUIDANCE CONSENSUS OF 60-70 PERCENT CHANCES ARE REASONABLE...BUT MAY NEED TO BE RAISED MORE IF THIS TIME PERIOD REMAINS CONSISTENT FOR PRECIPITATION. AFTER WEDNESDAY...ATTENTION TURNS TO THE SOUTHERN END OF THE SPLITTING UPPER TROUGH WHICH TURNS INTO AN UPPER LOW. SOME MODELS SUGGEST THE UPPER LOW COULD LIFT TOWARDS THE AREA ON FRIDAY. IF SO...THEN SOME SHOWERS COULD MOVE IN. FOR NOW...HAVE LOWER 20-40 PERCENT CHANCES FOR WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...ACCOUNTING FOR THE DIMINISHING MOISTURE STREAM AND THE APPROACH OF THE UPPER LOW. REGARDING THUNDER...REDUCED THESE PROBABILITIES TO 20 AND ONLY DURING THE DAYTIME HOURS FOR TUESDAY THROUGH THURSDAY...GIVEN LESS THAN 500 J/KG OF ONLY DAYTIME INSTABILITY SUGGESTED BY THE GFS. TEMPERATURES THROUGHOUT MUCH OF THE LONG TERM PERIOD WILL STAY WELL ABOVE NORMAL...UNTIL MAYBE FRIDAY NIGHT IF THE ECMWF IS RIGHT TRYING TO SHOW SOME COLDER AIR COMING DOWN FROM CANADA. IN ANY EVENT...850MB TEMPS DROP FROM 10-12C ON TUESDAY TO 6-8C BY 12Z FRIDAY. A BLEND OF MODEL GUIDANCE SEEMED REASONABLE. && .AVIATION...THIS AFTERNOON THROUGH SUNDAY 1231 PM CDT SAT MAR 17 2012 CONCERN THIS PERIOD IS THE INCREASING LOWER LEVEL MOISTURE/STRATUS OVER THE TAF SITES. VIS IMAGERY/SFC OBS SHOWED A BROAD AREA OF SCT TO OVC MVFR STRATUS ADVECTING NORTHEAST ACROSS IA AT MID-DAY...DUE INTO KRST AROUND 20Z AND KLSE AROUND 22Z. LEADING EDGE OF THE CIGS RISING WITH DIURNAL WARMING/MIXING TODAY TO NEAR MVFR/VFR THRESH- HOLD. WITH DIURNAL COOLING TONIGHT BKN CIGS TO LOWER BACK INTO MVFR. GIVEN THE EXTENT OF THE MOISTURE...THESE CLOUDS/CIGS LOOKING TO PERSIST THRU AT LEAST SUN MORNING. WITH ALL THE LOW LEVEL MOISTURE DIURNAL COOLING TONIGHT EXPECTED TO PRODUCE AREAS 3-5SM BR IN THE 08Z-15Z TIME-FRAME. PRESSURE GRADIENT OVER THE REGION WILL MAINTAIN SOUTH WINDS 10-20KTS G25-30KT DURING THE LATE MORNINGS/AFTERNOONS... WITH THE STRONGER/GUSTIER WINDS AT THE HIGHER ELEVATION OPEN COUNTRY SITES LIKE KRST/KAUM/KTOB. && .CLIMATE...TODAY THROUGH TUESDAY 310 AM CDT SAT MAR 17 2012 RECORD HIGHS AND RECORD WARM LOWS ARE POSSIBLE THROUGH TUESDAY... ESPECIALLY THIS WEEKEND...AS AN UNSEASONABLY WARM AND MOIST AIR MASS CONTINUES TO RESIDE ACROSS THE UPPER MIDWEST. TEMPERATURES SHOULD BEGIN COOLING MON/TUE AS CLOUDS/ -SHRA INCREASE ACROSS THE AREA. HOWEVER...RECORDS ON THOSE DAYS COMPARED TO FORECASTS STILL SUGGEST SOME POTENTIAL TO BREAK THEM. && .ARX WATCHES/WARNINGS/ADVISORIES... 310 AM CDT SAT MAR 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DAS CLIMATE......AJ/RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1229 PM CDT SAT MAR 17 2012 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY THROUGH SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SURFACE WARM FRONT LIFTING NORTHWARD OVER CENTRAL WISCONSIN EARLY THIS MORNING. TEMPS ARE IN THE LOW TO MID 50S NORTH OF THE FRONT...AND IN THE MID TO UPPER 60S SOUTH OF THE BOUNDARY. TEMPS ARE LOCALLY COOLER NEAR LAKE MICHIGAN WITH SOME OF THAT MARINE AIR CURLING AROUND INTO SHAWANO WHERE TEMPS ARE IN THE LOWER 40S WITHIN DENSE FOG. WIDELY SCT SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER NORTH-CENTRAL WISCONSIN HAVE BEEN WEAKENING AND WILL LIKELY EXIT THE AREA BY PRESS TIME. ADDITIONAL ECHOES HAVE POPPED UP WITHIN THE INSTABILITY AXIS OVER SW WISCONSIN AND NORTHWEST ILLINOIS...AND WILL ADD ISOLATED SHOWERS AND THUNDERSTORMS NEARLY EVERYWHERE THROUGH MID-MORNING. WITH VERY WARM AND UNSTABLE AIR MOVING INTO THE REGION TODAY...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN...FOLLOWED BY TEMPS AND MARINE FOG. TODAY...SURFACE WARM FRONT...WHICH SNAKES ACROSS WISCONSIN FROM NW TO SE...WILL LIFT NORTH OF THE AREA THIS MORNING...WHICH WILL TURN WINDS TO THE SOUTH EXCEPT ACROSS FAR NE WISCONSIN. SE WINDS HERE...ENHANCED BY THE LAKE BREEZE THIS AFTERNOON...WILL KEEP WAVES OF MARINE STRATUS AND FOG PROCEEDING INLAND AT TIMES. OTHERWISE...850MB MOISTURE AND INSTABILITY AXIS WILL BE OVERHEAD TODAY...WITH ML CAPES REACHING CLOSE TO 2500 J/KG WITH NO CIN THIS AFTERNOON. TOUGH TO IDENTIFY A TRIGGER UPSTREAM THAT COULD TAP INTO THIS INSTABILITY FOR THUNDERSTORM DEVELOPMENT...AND MAY JUST END UP WITH BUBBLY CU...WHICH OCCURRED UPSTREAM TODAY. THERE ARE A COUPLE WEAK IMPULSES UPSTREAM...OVER NW IOWA AND ANOTHER OVER WESTERN NEBRASKA...BUT TOUGH TO SAY IF THEY WILL BE STRONG ENOUGH TO TRIGGER CONVECTION. THE BEST THING TO LATCH ONTO IS THE SE FLOW OVER THE DOOR...WHICH COULD GET ENHANCED BY THE LAKE BREEZE COMPONENT TO CREATE CONVERGENCE OVER NE WISCONSIN. SYNOPTIC FLOW WILL BE OUT OF THE SOUTH...NOT OUT OF THE SOUTHWEST OR WEST WHICH WOULD BE MORE PREFERRED. STILL THOUGH...THAT MAGNITUDE OF CAPE CANNOT BE IGNORED SO WILL KEEP AN ISOLATED MENTION OF SHOWERS AND THUNDERSTORMS OVER NE WISCONSIN FOR THIS AFTERNOON. 925MB TEMPS 18C TO 20C CALL FOR HIGHS IN THE UPPER 70S TO LOWER 80S. TONIGHT...850MB MOISTURE AND INSTABILITY AXIS WILL REMAIN OVERHEAD. LLJ WILL DEVELOP OVER WESTERN WISCONSIN WITH A NOSE POINTED INTO LAKE SUPERIOR. ANY KIND OF WEAK SHORTWAVE IMPULSE COULD INITIATE CONVECTION WITH MID-LEVEL LAPSE RATES GREATER THAN 8C...BUT TOUGH TO IDENTIFY ANY FEATURES ON SATELLITE OR IN THE MODELS. IF SOMETHING WERE TO POP...WESTERN WISCONSIN LOOKS BETTER ON PAPER. BUT UNCERTAINTY IS TOO HIGH TO INCLUDE IN THE FORECAST. OTHERWISE...SOUTH FLOW WILL AGAIN SEND WAVES OF MARINE STRATUS AND FOG NORTH ALONG THE LAKESHORE AND ACROSS DOOR COUNTY AND FAR NE WISCONSIN. A WARM NIGHT AHEAD WITH LOWS IN THE MID TO UPPER 50S. SUNDAY...SHORTWAVE ENERGY WILL PASS SOUTH OF THE AREA WHILE MID-LEVEL HEIGHTS BUILD OVERHEAD. AS A RESULT...SEEING STRONGER CAPPING ON PROGGED SOUNDINGS WHICH SHOULD KEEP A LID ON SHOWER AND THUNDERSTORM DEVELOPMENT. WILL GO DRY ONCE AGAIN. HIGHS AGAIN IN THE UPPER 70S TO LOWER 80S...BUT COOLER NEAR LAKE MICHIGAN WHERE THE ONSHORE COMPONENT WILL BE A LITTLE STRONGER. .LONG TERM...SUNDAY NIGHT THRU FRIDAY. MAIN FORECAST CHALLENGES ARE TEMPS...PRECIP CHANCES...AND FOG POTENTIAL. SUMMER-LIKE PATTERN CONTINUES INTO EARLY NEXT WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN U.S. AND SOUTHERLY FLOW USHERS IN WARM AIR AND RELATIVELY HIGH DEWPOINTS. TROUGH ACROSS THE WESTERN U.S. WILL CROSS INTO THE PLAINS ON WEDNESDAY...AND TRANSITION INTO A CUT OFF LOW THAT SLOWLY MOVES SOUTH OF THE GREAT LAKES LATE NEXT WEEK. MODELS DISAGREE ON THE EVOLUTION FROM A LONGWAVE TROUGH TO A CUT OFF LOW...BOTH WITH LOCATION AND TIMING...BRINGING PLENTY OF UNCERTAINTY INTO THE FORECAST. IN GENERAL...PLAN TO FOLLOW A GFS/ECMWF BLEND. SUNDAY NIGHT IS STILL LOOKING DRY...AS THE AREA REMAINS UNDER UPPER RIDGING AND NO OBVIOUS TRIGGER FOR CONVECTION. CANNOT TOTALLY RULE OUT A STRAY SHOWER OR STORM AS STEEP LAPSE RATES REMAIN OVER THE AREA...BUT PREFER TO STAY WITH A DRY FORECAST. CLOUDS WILL BE ON THE INCREASE OVERNIGHT AND ON MONDAY MORNING THOUGH...AS MOISTURE INCREASES ALOFT. WILL START TO INCREASE POPS ON MONDAY AND MONDAY NIGHT OVER THE AREA AS UPPER TROUGH AND SHORTWAVE ENERGY APPROACH THE AREA. STILL BELIEVE THE MAJORITY OF THE ACTIVITY WILL STAY TO OUR WEST...WHERE THE BETTER MOISTURE/FORCING AND BAROCLINIC ZONE IS LOCATED...BUT WILL CARRY LOW CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL WI...WITH SLIGHT CHANCE POPS BUFFERING THIS AREA TO THE EAST. THE EXTENDED DRY SPELL (AT LEAST FOR MOST LOCATIONS) WILL COME TO AN END TUESDAY OR WEDNESDAY...AS THE UPPER TROUGH AND A NORTHERN PLAINS SHORTWAVE CONVERGE ON THE AREA. POPS WILL NEED TO BE ADJUSTED FOR TUESDAY AS THE TIMING IS PINNED DOWN...BUT PLAN TO STICK WITH CHANCE POPS WEST AND SLIGHTS EAST TO COVER FOR NOW. HIGHEST POPS WILL BE PLACED ON WEDNESDAY...AS THERE IS ENOUGH MODEL CONSENSUS SHOWING PRECIP OVER THE AREA. THE UNSETTLED WEATHER LOOKS TO CONTINUE INTO THE END OF THE WEEK AS THE UPPER LOW DRIFTS SOUTH OF THE AREA...HOWEVER CONFIDENCE IS LOW ON THE OVERALL PATTERN. WITH MODELS DIFFERING ON THE TIMING AND LOCATION OF THE CUT OFF LOW...AS WELL AS A POSSIBLE SHORTWAVE OVER THE NORTHERN PLAINS...IT WILL BE HARD TO SAY WITH CONFIDENCE WHERE THE BEST CHANCES FOR PRECIP RESIDE AND WHEN TO GO DRY. HAVE LOW CHANCE AND SLIGHT POPS TO COVER THIS UNCERTAINTY. DOWNPLAYED THUNDER POTENTIAL FOR MANY OF THE PERIODS...ESPECIALLY AT NIGHT...AS CONVECTIVE PARAMETERS ARE NOT OVERLY IMPRESSIVE. AS FOR FOG...WILL CONTINUE TO HIGHLIGHT ON LAKE MICHIGAN AND MUCH OF THE BAY THROUGH MID-WEEK AS UNSEASONABLY HIGH DEWPOINTS TRAVEL ACROSS THE RELATIVELY COOLER WATERS. WILL ALSO MENTION FOG ALONG THE IMMEDIATE SHORELINE AS ANY FOG BANK THAT DEVELOPS COULD DRIFT INLAND. WITH DEWPOINTS IN THE 50S TO NEAR 60 THROUGH MID- WEEK...DO EXPECT PATCHY FOG ELSEWHERE SOME NIGHTS IF WINDS CAN DECOUPLE AND SKIES ARE CLEAR. BEST CHANCE FOR THIS WILL BE SUNDAY NIGHT...SO WILL CONTINUE TO MENTION FOG ACROSS THE ENTIRE CWA. WINDS LOOK TO STAY UP THE REST OF THE NIGHTS TO KEEP THE THREAT OF FOG LOW. RECORD OR NEAR RECORD WARMTH WILL CONTINUE ON MONDAY AND TUESDAY AS PERSISTENT SOUTHERLY FLOW CONTINUES TO USHER IN WELL ABOVE NORMAL TEMPS. TUESDAY LOOKS TO BE THE LAST DAY IN THE 70S FOR PORTIONS OF CENTRAL AND EAST-CENTRAL WISCONSIN...BEFORE THE CLOUDS AND PRECIP HOLD TEMPS IN THE MID/UPPER 50S NORTH AND LOW 60S SOUTH FOR THE END OF THE WORK WEEK. THESE MAY BE A LITTLE GENEROUS IF PRECIP/CLOUD COVER ARE WIDESPREAD ENOUGH. ALTHOUGH TEMPS WILL BE SIGNIFICANTLY COOLER LATE IN THE WEEK COMPARED TO EARLY IN THE WEEK...THEY WILL REMAIN ABOVE NORMAL. && .AVIATION...VFR CONDITIONS EXPECTED THRU THIS EVENING AND THEN QUESTIONS ARISE AS TO HOW MUCH FOG WL BE ABLE TO DVLP DURING THE OVERNIGHT HOURS. PREVAILING SOUTHERLY WINDS WL CONT TO PUMP WARM/ MOIST AIR INTO NE WI AND WITH SURFACE WINDS DIMINISHING TO 5 TO 10 KTS LATER TNGT...AT LEAST PATCHY FOG/STRATUS DECK SHOULD FORM. FOR NOW...HAVE MENTIONED MVFR VSBYS MAINLY AFTER MIDNGT AND CONTINUING THRU 14Z SUNDAY. AN ISOLATED TSTM COULD ALSO POP TNGT AS A SHORTWAVE LIFTS NE TOWARD SRN SECTIONS OF THE GREAT LKS. BELIEVE ANY TSTM ACTIVITY TO BE TOO ISOLATED TO MENTION IN TAFS. LASTLY...HAVE KEPT SOME MENTION OF LLWS TONIGHT AS WINDS JUST ABOVE THE SURFACE COULD REACH 35 KTS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ AK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
710 AM CDT SAT MAR 17 2012 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 310 AM CDT SAT MAR 17 2012 MAIN FORECAST CONCERNS ARE ON ANY CHANCES FOR PRECIPITATION THROUGH SUNDAY NIGHT...WINDS AND THE UNPRECEDENTED WARMTH. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING JUST OFF THE CALIFORNIA COAST WHILE BROAD RIDGING WAS BUILDING DOWNSTREAM OVER THE EASTERN TWO THIRDS OF THE U.S.. RIDGE AXIS SITS OVER THE GREAT LAKES...PLACING THE FORECAST AREA UNDER SOUTHWEST FLOW. WITHIN THIS SOUTHWEST FLOW...A WEAK SHORTWAVE COMBINED WITH A WARM FRONTAL BOUNDARY AND INCREASING LOW LEVEL JET TO PRODUCE A CLUSTER OF STRONG TO SEVERE SHOWERS AND THUNDERSTORMS LAST EVENING OVER CENTRAL WISCONSIN. THESE HAVE SINCE LIFTED INTO UPPER MICHIGAN THANKS TO THE SHORTWAVE MOVING NORTHEAST AND A 30-40 KT SOUTHWEST JET AT 850MB. WITHIN THIS SOUTHWEST FLOW...THE ONLY SHORTWAVES OF NOTE ARE WEAK ONES IN NEBRASKA...AND THESE ARE NOT PRODUCING MUCH CLOUDS AT ALL. WITH THE FORECAST AREA UNDER THAT STRONG SOUTHWEST JET AND A RELATIVELY TIGHT PRESSURE GRADIENT AT THE SURFACE AHEAD OF A TROUGH IN THE DAKOTAS... TEMPERATURES HAVE STRUGGLED TO FALL. READINGS ARE ONLY IN THE 60S. DEWPOINTS ARE ALSO STAYING UP IN THE MID TO UPPER 50S. AIRMASS IS ALSO SEMI-CAPPED AND DRY...LOOKING AT THE 00Z DVN SOUNDING. GOING FARTHER SOUTHWEST TO OAX AND IT DRIES OUT EVEN MORE. DESPITE THE DRIER AIR...THERE IS ENOUGH INSTABILITY WHEN LIFTED FROM 800MB /APPROX 700 J/KG/ TO PRODUCE PRECIPITATION. A ZONE OF 800MB SPEED CONVERGENCE IN SOUTHWEST WISCONSIN AND NORTHWEST ILLINOIS HAS PRODUCED SOME SHOWERS DOWN THERE. TODAY THROUGH SUNDAY NIGHT...UPPER TROUGHING APPROACHING THE WEST COAST OF THE U.S. RIGHT NOW IS PROGGED BY ALL MODELS TO MOVE INTO THE ROCKIES BY 12Z MONDAY. A FAIRLY DEEP LOW PRESSURE SYSTEM ENDS UP DEVELOPING OVER EASTERN MONTANA AS THIS TROUGH MOVES EAST...ALLOWING FOR STRONG SOUTHERLY FLOW TO PERSIST DOWNSTREAM INTO OUR FORECAST AREA. A COUPLE OF IMPACTS FROM THIS STRONG SOUTHERLY FLOW INCLUDE: 1. HELPING TO MAINTAIN THE UNSEASONABLY HIGH DEWPOINTS...WHICH COULD EXCEED 60F AT TIMES BETWEEN 15-18Z BEFORE DROPPING DUE TO MIXING. 2. MAINTAIN THE UNSEASONABLY WARM 925 AND 850MB TEMPS...WHICH ARE PROGGED TO STAY BETWEEN 16-20C AND 12-14C RESPECTIVELY. THESE READINGS ARE VERY SIMILAR TO WHAT WAS SEEN FRIDAY...SO HIGH TEMPERATURES BOTH TODAY AND SUNDAY ARE LIKELY TO BE SIMILAR. SOME HINTS FROM MET GUIDANCE WHICH DID WELL YESTERDAY THAT SITES SUCH AS BOSCOBEL COULD HIT THE MID 80S. GENERALLY FOLLOWED THIS. 3. A LOT OF GUSTY WINDS THROUGHOUT. APPEARS THAT WHEN LOOKING AT SOUNDINGS...MIXING DEPTHS AT MOST APPROACH 850MB. MOMENTUM TRANSFER FROM THIS LEVEL KEEPS WINDS BELOW ADVISORY CRITERIA...EVEN AT RST. 4. RESULTING FROM ITEMS 1-3 ABOVE...LOW TEMPERATURES ARE GOING TO STAY VERY WARM FOR THIS TIME OF YEAR...LIKELY STRUGGLING TO GET MUCH BELOW 60. REGARDING PRECIPITATION...TRIGGERS ARE VERY HARD TO FIND THROUGH SUNDAY NIGHT. IN ADDITION...THE AIRMASS LOOKS A LITTLE MORE CAPPED PER RUC/GFS SOUNDINGS. WE DO HAVE THE WEAK SHORTWAVES IN NEBRASKA COMING ACROSS THE FORECAST AREA AT 18Z TODAY...BUT THERE IS NO SURFACE CONVERGENT FEATURE LIKE YESTERDAY WITH THE WARM FRONT. IN FACT...NO SURFACE CONVERGENT FEATURES ARE PRESENT THROUGH SUNDAY NIGHT. AFTER 06Z SUNDAY NIGHT...THERE ARE INDICATIONS OF A SHORTWAVE COMING ACROSS SOUTHEAST MINNESOTA...AS WELL AS ISENTROPIC LIFT ON THE 305-310 K SURFACES. THE 17.00Z GFS/CANADIAN BOTH HINT AT POTENTIAL FOR SOME CONVECTION IN THIS AREA...SO INCLUDED SOME 20 PERCENT CHANCES FOR NOW...GIVEN NAM/UKMET/ECMWF DRY. FOR THE REST OF THE PERIOD...ALL MODELS ARE PRETTY MUCH DRY THROUGH SUNDAY WHICH SEEMS REASONABLE. MONDAY AND MONDAY NIGHT...THE UPPER TROUGHING OVER THE ROCKIES IS FORECAST TO INCH EASTWARD...WITH ITS AXIS FROM EASTERN MONTANA INTO NEW MEXICO AT 12Z TUESDAY. ALTHOUGH THIS TROUGH IS FAR AWAY FROM THE AREA...WE WILL SEE 10-30 METER 500MB HEIGHT FALLS EACH 12 HOUR PERIOD OVER THE FORECAST AREA...HIGHEST WEST. THESE HEIGHT FALLS COMBINED WITH STRONG MOISTURE TRANSPORT ON A SOUTHERLY 40-60 KT 850MB JET WILL YIELD INCREASING PRECIPITATION CHANCES...ESPECIALLY AGAIN OVER THE WEST. PRECIPITABLE WATER VALUES CLIMB TO 1-1.4 INCHES WHICH WOULD SUPPORT SOME DECENT PRECIPITATION TOO. CAPE VALUES ARE RESTRICTED SOMEWHAT DUE TO CLOUD COVER...PERHAPS UP TO 500 J/KG OF VERY THIN MUCAPE. THIS SHOULD LIMIT THUNDER COVERAGE TOO. DESPITE THE INCREASED CLOUD COVER AND PRECIPITATION...STILL ANTICIPATING TEMPERATURES TO RISE INTO THE 70S ON MONDAY...WARMEST EAST WHERE SOME SUN COULD OCCUR. LOWS STAY UP TOO MONDAY NIGHT WITH THE SURFACE COLD FRONT STILL WAY OFF TO THE WEST IN THE EASTERN DAKOTAS. .LONG TERM...TUESDAY THROUGH FRIDAY NIGHT 310 AM CDT SAT MAR 17 2012 LONG TERM FORECAST IS BECOMING MORE UNCERTAIN...PRIMARILY BECAUSE MODELS ARE STRUGGLING ON HOW TO HANDLE THE WESTERN U.S. TROUGH FROM MONDAY NIGHT. 17.00Z ECMWF/GFS/CANADIAN AND MOST GFS ENSEMBLES ALL SUGGEST THE TROUGH WILL CUT-OFF AS IT CROSSES THE PLAINS TUESDAY AND WEDNESDAY...BUT EXACTLY WHEN AND THEN HOW TO HANDLE THIS UPPER LOW VARIES AMONG EVERY MODEL. THERE STILL REMAINS A FEW GFS ENSEMBLES AND THE 17.00Z UKMET THAT SUGGEST THE TROUGH STAYS TOGETHER... FOLLOWING THE 16.12Z ECMWF IDEA. HOWEVER...OVER THE LAST COUPLE DAYS OF MODEL RUNS...THESE SEEM TO BE AN OUTLIER. THEREFORE PREFERENCE IS TO FOLLOW THE MAJORITY 17.00Z GUIDANCE. AS THE UPPER TROUGH APPROACHES THE FORECAST AREA TUESDAY INTO WEDNESDAY...THE MOISTURE STREAM REFERENCED IN THE MONDAY/MONDAY NIGHT DISCUSSION WILL FULLY SHIFT OVERHEAD. SEEMS LIKE TUESDAY NIGHT IS THE BEST PERIOD FOR THE ENTIRE FORECAST AREA TO SEE RAIN. MODEL GUIDANCE CONSENSUS OF 60-70 PERCENT CHANCES ARE REASONABLE...BUT MAY NEED TO BE RAISED MORE IF THIS TIME PERIOD REMAINS CONSISTENT FOR PRECIPITATION. AFTER WEDNESDAY...ATTENTION TURNS TO THE SOUTHERN END OF THE SPLITTING UPPER TROUGH WHICH TURNS INTO AN UPPER LOW. SOME MODELS SUGGEST THE UPPER LOW COULD LIFT TOWARDS THE AREA ON FRIDAY. IF SO...THEN SOME SHOWERS COULD MOVE IN. FOR NOW...HAVE LOWER 20-40 PERCENT CHANCES FOR WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...ACCOUNTING FOR THE DIMINISHING MOISTURE STREAM AND THE APPROACH OF THE UPPER LOW. REGARDING THUNDER...REDUCED THESE PROBABILITIES TO 20 AND ONLY DURING THE DAYTIME HOURS FOR TUESDAY THROUGH THURSDAY...GIVEN LESS THAN 500 J/KG OF ONLY DAYTIME INSTABILITY SUGGESTED BY THE GFS. TEMPERATURES THROUGHOUT MUCH OF THE LONG TERM PERIOD WILL STAY WELL ABOVE NORMAL...UNTIL MAYBE FRIDAY NIGHT IF THE ECMWF IS RIGHT TRYING TO SHOW SOME COLDER AIR COMING DOWN FROM CANADA. IN ANY EVENT...850MB TEMPS DROP FROM 10-12C ON TUESDAY TO 6-8C BY 12Z FRIDAY. A BLEND OF MODEL GUIDANCE SEEMED REASONABLE. && .AVIATION...TODAY AND TONIGHT 710 AM CDT SAT MAR 17 2012 THE AREA WILL REMAIN IN SOUTHERLY AIRFLOW THROUGH THE PERIOD...WITH GUSTY CONDITIONS EXPECTED TO DEVELOP BY LATE MORNING AND THEN SUBSIDING AROUND SUNSET. LOOK FOR SOUTHERLY WIND GUSTS IN THE 25-30KT RANGE. OTHERWISE...VFR CONDITION EXPECTED THROUGH THE PERIOD. LOOK FOR SOME CUMULUS DEVELOPMENT TODAY...BUT FAIRLY STRONG CAP ALOFT IN THE ATMOSPHERE EXPECTED TO INHIBIT DEEP CONVECTION SHRA/TS ACTIVITY. && .CLIMATE...TODAY THROUGH TUESDAY 310 AM CDT SAT MAR 17 2012 RECORD HIGHS AND RECORD WARM LOWS ARE POSSIBLE THROUGH TUESDAY... ESPECIALLY THIS WEEKEND...AS AN UNSEASONABLY WARM AND MOIST AIR MASS CONTINUES TO RESIDE ACROSS THE UPPER MIDWEST. TEMPERATURES SHOULD BEGIN COOLING MON/TUE AS CLOUDS/ -SHRA INCREASE ACROSS THE AREA. HOWEVER...RECORDS ON THOSE DAYS COMPARED TO FORECASTS STILL SUGGEST SOME POTENTIAL TO BREAK THEM. && .ARX WATCHES/WARNINGS/ADVISORIES... 310 AM CDT SAT MAR 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DAS CLIMATE......AJ/RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
622 AM CDT SAT MAR 17 2012 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY THROUGH SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SURFACE WARM FRONT LIFTING NORTHWARD OVER CENTRAL WISCONSIN EARLY THIS MORNING. TEMPS ARE IN THE LOW TO MID 50S NORTH OF THE FRONT...AND IN THE MID TO UPPER 60S SOUTH OF THE BOUNDARY. TEMPS ARE LOCALLY COOLER NEAR LAKE MICHIGAN WITH SOME OF THAT MARINE AIR CURLING AROUND INTO SHAWANO WHERE TEMPS ARE IN THE LOWER 40S WITHIN DENSE FOG. WIDELY SCT SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER NORTH-CENTRAL WISCONSIN HAVE BEEN WEAKENING AND WILL LIKELY EXIT THE AREA BY PRESS TIME. ADDITIONAL ECHOES HAVE POPPED UP WITHIN THE INSTABILITY AXIS OVER SW WISCONSIN AND NORTHWEST ILLINOIS...AND WILL ADD ISOLATED SHOWERS AND THUNDERSTORMS NEARLY EVERYWHERE THROUGH MID-MORNING. WITH VERY WARM AND UNSTABLE AIR MOVING INTO THE REGION TODAY...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN...FOLLOWED BY TEMPS AND MARINE FOG. TODAY...SURFACE WARM FRONT...WHICH SNAKES ACROSS WISCONSIN FROM NW TO SE...WILL LIFT NORTH OF THE AREA THIS MORNING...WHICH WILL TURN WINDS TO THE SOUTH EXCEPT ACROSS FAR NE WISCONSIN. SE WINDS HERE...ENHANCED BY THE LAKE BREEZE THIS AFTERNOON...WILL KEEP WAVES OF MARINE STRATUS AND FOG PROCEEDING INLAND AT TIMES. OTHERWISE...850MB MOISTURE AND INSTABILITY AXIS WILL BE OVERHEAD TODAY...WITH ML CAPES REACHING CLOSE TO 2500 J/KG WITH NO CIN THIS AFTERNOON. TOUGH TO IDENTIFY A TRIGGER UPSTREAM THAT COULD TAP INTO THIS INSTABILITY FOR THUNDERSTORM DEVELOPMENT...AND MAY JUST END UP WITH BUBBLY CU...WHICH OCCURRED UPSTREAM TODAY. THERE ARE A COUPLE WEAK IMPULSES UPSTREAM...OVER NW IOWA AND ANOTHER OVER WESTERN NEBRASKA...BUT TOUGH TO SAY IF THEY WILL BE STRONG ENOUGH TO TRIGGER CONVECTION. THE BEST THING TO LATCH ONTO IS THE SE FLOW OVER THE DOOR...WHICH COULD GET ENHANCED BY THE LAKE BREEZE COMPONENT TO CREATE CONVERGENCE OVER NE WISCONSIN. SYNOPTIC FLOW WILL BE OUT OF THE SOUTH...NOT OUT OF THE SOUTHWEST OR WEST WHICH WOULD BE MORE PREFERRED. STILL THOUGH...THAT MAGNITUDE OF CAPE CANNOT BE IGNORED SO WILL KEEP AN ISOLATED MENTION OF SHOWERS AND THUNDERSTORMS OVER NE WISCONSIN FOR THIS AFTERNOON. 925MB TEMPS 18C TO 20C CALL FOR HIGHS IN THE UPPER 70S TO LOWER 80S. TONIGHT...850MB MOISTURE AND INSTABILITY AXIS WILL REMAIN OVERHEAD. LLJ WILL DEVELOP OVER WESTERN WISCONSIN WITH A NOSE POINTED INTO LAKE SUPERIOR. ANY KIND OF WEAK SHORTWAVE IMPULSE COULD INITIATE CONVECTION WITH MID-LEVEL LAPSE RATES GREATER THAN 8C...BUT TOUGH TO IDENTIFY ANY FEATURES ON SATELLITE OR IN THE MODELS. IF SOMETHING WERE TO POP...WESTERN WISCONSIN LOOKS BETTER ON PAPER. BUT UNCERTAINTY IS TOO HIGH TO INCLUDE IN THE FORECAST. OTHERWISE...SOUTH FLOW WILL AGAIN SEND WAVES OF MARINE STRATUS AND FOG NORTH ALONG THE LAKESHORE AND ACROSS DOOR COUNTY AND FAR NE WISCONSIN. A WARM NIGHT AHEAD WITH LOWS IN THE MID TO UPPER 50S. SUNDAY...SHORTWAVE ENERGY WILL PASS SOUTH OF THE AREA WHILE MID-LEVEL HEIGHTS BUILD OVERHEAD. AS A RESULT...SEEING STRONGER CAPPING ON PROGGED SOUNDINGS WHICH SHOULD KEEP A LID ON SHOWER AND THUNDERSTORM DEVELOPMENT. WILL GO DRY ONCE AGAIN. HIGHS AGAIN IN THE UPPER 70S TO LOWER 80S...BUT COOLER NEAR LAKE MICHIGAN WHERE THE ONSHORE COMPONENT WILL BE A LITTLE STRONGER. .LONG TERM...SUNDAY NIGHT THRU FRIDAY. MAIN FORECAST CHALLENGES ARE TEMPS...PRECIP CHANCES...AND FOG POTENTIAL. SUMMER-LIKE PATTERN CONTINUES INTO EARLY NEXT WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN U.S. AND SOUTHERLY FLOW USHERS IN WARM AIR AND RELATIVELY HIGH DEWPOINTS. TROUGH ACROSS THE WESTERN U.S. WILL CROSS INTO THE PLAINS ON WEDNESDAY...AND TRANSITION INTO A CUT OFF LOW THAT SLOWLY MOVES SOUTH OF THE GREAT LAKES LATE NEXT WEEK. MODELS DISAGREE ON THE EVOLUTION FROM A LONGWAVE TROUGH TO A CUT OFF LOW...BOTH WITH LOCATION AND TIMING...BRINGING PLENTY OF UNCERTAINTY INTO THE FORECAST. IN GENERAL...PLAN TO FOLLOW A GFS/ECMWF BLEND. SUNDAY NIGHT IS STILL LOOKING DRY...AS THE AREA REMAINS UNDER UPPER RIDGING AND NO OBVIOUS TRIGGER FOR CONVECTION. CANNOT TOTALLY RULE OUT A STRAY SHOWER OR STORM AS STEEP LAPSE RATES REMAIN OVER THE AREA...BUT PREFER TO STAY WITH A DRY FORECAST. CLOUDS WILL BE ON THE INCREASE OVERNIGHT AND ON MONDAY MORNING THOUGH...AS MOISTURE INCREASES ALOFT. WILL START TO INCREASE POPS ON MONDAY AND MONDAY NIGHT OVER THE AREA AS UPPER TROUGH AND SHORTWAVE ENERGY APPROACH THE AREA. STILL BELIEVE THE MAJORITY OF THE ACTIVITY WILL STAY TO OUR WEST...WHERE THE BETTER MOISTURE/FORCING AND BAROCLINIC ZONE IS LOCATED...BUT WILL CARRY LOW CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL WI...WITH SLIGHT CHANCE POPS BUFFERING THIS AREA TO THE EAST. THE EXTENDED DRY SPELL (AT LEAST FOR MOST LOCATIONS) WILL COME TO AN END TUESDAY OR WEDNESDAY...AS THE UPPER TROUGH AND A NORTHERN PLAINS SHORTWAVE CONVERGE ON THE AREA. POPS WILL NEED TO BE ADJUSTED FOR TUESDAY AS THE TIMING IS PINNED DOWN...BUT PLAN TO STICK WITH CHANCE POPS WEST AND SLIGHTS EAST TO COVER FOR NOW. HIGHEST POPS WILL BE PLACED ON WEDNESDAY...AS THERE IS ENOUGH MODEL CONSENSUS SHOWING PRECIP OVER THE AREA. THE UNSETTLED WEATHER LOOKS TO CONTINUE INTO THE END OF THE WEEK AS THE UPPER LOW DRIFTS SOUTH OF THE AREA...HOWEVER CONFIDENCE IS LOW ON THE OVERALL PATTERN. WITH MODELS DIFFERING ON THE TIMING AND LOCATION OF THE CUT OFF LOW...AS WELL AS A POSSIBLE SHORTWAVE OVER THE NORTHERN PLAINS...IT WILL BE HARD TO SAY WITH CONFIDENCE WHERE THE BEST CHANCES FOR PRECIP RESIDE AND WHEN TO GO DRY. HAVE LOW CHANCE AND SLIGHT POPS TO COVER THIS UNCERTAINTY. DOWNPLAYED THUNDER POTENTIAL FOR MANY OF THE PERIODS...ESPECIALLY AT NIGHT...AS CONVECTIVE PARAMETERS ARE NOT OVERLY IMPRESSIVE. AS FOR FOG...WILL CONTINUE TO HIGHLIGHT ON LAKE MICHIGAN AND MUCH OF THE BAY THROUGH MID-WEEK AS UNSEASONABLY HIGH DEWPOINTS TRAVEL ACROSS THE RELATIVELY COOLER WATERS. WILL ALSO MENTION FOG ALONG THE IMMEDIATE SHORELINE AS ANY FOG BANK THAT DEVELOPS COULD DRIFT INLAND. WITH DEWPOINTS IN THE 50S TO NEAR 60 THROUGH MID- WEEK...DO EXPECT PATCHY FOG ELSEWHERE SOME NIGHTS IF WINDS CAN DECOUPLE AND SKIES ARE CLEAR. BEST CHANCE FOR THIS WILL BE SUNDAY NIGHT...SO WILL CONTINUE TO MENTION FOG ACROSS THE ENTIRE CWA. WINDS LOOK TO STAY UP THE REST OF THE NIGHTS TO KEEP THE THREAT OF FOG LOW. RECORD OR NEAR RECORD WARMTH WILL CONTINUE ON MONDAY AND TUESDAY AS PERSISTENT SOUTHERLY FLOW CONTINUES TO USHER IN WELL ABOVE NORMAL TEMPS. TUESDAY LOOKS TO BE THE LAST DAY IN THE 70S FOR PORTIONS OF CENTRAL AND EAST-CENTRAL WISCONSIN...BEFORE THE CLOUDS AND PRECIP HOLD TEMPS IN THE MID/UPPER 50S NORTH AND LOW 60S SOUTH FOR THE END OF THE WORK WEEK. THESE MAY BE A LITTLE GENEROUS IF PRECIP/CLOUD COVER ARE WIDESPREAD ENOUGH. ALTHOUGH TEMPS WILL BE SIGNIFICANTLY COOLER LATE IN THE WEEK COMPARED TO EARLY IN THE WEEK...THEY WILL REMAIN ABOVE NORMAL. && .AVIATION...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE MAKING THERE WAY EAST ACROSS THE EASTERN HALF OF WISCONSIN THIS MORNING. THESE STORMS ARE EXPECTED TO DISSIPATE BY LATE MORNING. PATCHY MVFR VSBYS IN MIST OVER NORTH-CENTRAL WISCONSIN WILL QUICKLY TURN VFR WITH DAYTIME HEATING AN HOUR OR TWO AFTER THE 12Z ISSUANCE. OTHERWISE VFR CONDITIONS THROUGH THE TAF PERIOD. LLWS DEVELOPS AGAIN TONIGHT OVER NORTH-CENTRAL WISCONSIN. MPC && .MARINE...AREAS OF DENSE MARINE FOG SEEM MOST CONCENTRATED ADJACENT TO THE DOOR PENINSULA...AND THE CENTRAL AND NORTHERN PORTIONS OF GREEN BAY. WITH COORD FROM MKX...WILL CANCEL THE MARINE DENSE FOG ADVISORY FOR AREAS SOUTH OF THE DOOR. WILL LEAVE A MENTION OF PATCHY DENSE FOG THROUGH SUNDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
350 AM CDT SAT MAR 17 2012 .SHORT TERM...TODAY THROUGH SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SURFACE WARM FRONT LIFTING NORTHWARD OVER CENTRAL WISCONSIN EARLY THIS MORNING. TEMPS ARE IN THE LOW TO MID 50S NORTH OF THE FRONT...AND IN THE MID TO UPPER 60S SOUTH OF THE BOUNDARY. TEMPS ARE LOCALLY COOLER NEAR LAKE MICHIGAN WITH SOME OF THAT MARINE AIR CURLING AROUND INTO SHAWANO WHERE TEMPS ARE IN THE LOWER 40S WITHIN DENSE FOG. WIDELY SCT SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER NORTH-CENTRAL WISCONSIN HAVE BEEN WEAKENING AND WILL LIKELY EXIT THE AREA BY PRESS TIME. ADDITIONAL ECHOES HAVE POPPED UP WITHIN THE INSTABILITY AXIS OVER SW WISCONSIN AND NORTHWEST ILLINOIS...AND WILL ADD ISOLATED SHOWERS AND THUNDERSTORMS NEARLY EVERYWHERE THROUGH MID-MORNING. WITH VERY WARM AND UNSTABLE AIR MOVING INTO THE REGION TODAY...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN...FOLLOWED BY TEMPS AND MARINE FOG. TODAY...SURFACE WARM FRONT...WHICH SNAKES ACROSS WISCONSIN FROM NW TO SE...WILL LIFT NORTH OF THE AREA THIS MORNING...WHICH WILL TURN WINDS TO THE SOUTH EXCEPT ACROSS FAR NE WISCONSIN. SE WINDS HERE...ENHANCED BY THE LAKE BREEZE THIS AFTERNOON...WILL KEEP WAVES OF MARINE STRATUS AND FOG PROCEEDING INLAND AT TIMES. OTHERWISE...850MB MOISTURE AND INSTABILITY AXIS WILL BE OVERHEAD TODAY...WITH ML CAPES REACHING CLOSE TO 2500 J/KG WITH NO CIN THIS AFTERNOON. TOUGH TO IDENTIFY A TRIGGER UPSTREAM THAT COULD TAP INTO THIS INSTABILITY FOR THUNDERSTORM DEVELOPMENT...AND MAY JUST END UP WITH BUBBLY CU...WHICH OCCURRED UPSTREAM TODAY. THERE ARE A COUPLE WEAK IMPULSES UPSTREAM...OVER NW IOWA AND ANOTHER OVER WESTERN NEBRASKA...BUT TOUGH TO SAY IF THEY WILL BE STRONG ENOUGH TO TRIGGER CONVECTION. THE BEST THING TO LATCH ONTO IS THE SE FLOW OVER THE DOOR...WHICH COULD GET ENHANCED BY THE LAKE BREEZE COMPONENT TO CREATE CONVERGENCE OVER NE WISCONSIN. SYNOPTIC FLOW WILL BE OUT OF THE SOUTH...NOT OUT OF THE SOUTHWEST OR WEST WHICH WOULD BE MORE PREFERRED. STILL THOUGH...THAT MAGNITUDE OF CAPE CANNOT BE IGNORED SO WILL KEEP AN ISOLATED MENTION OF SHOWERS AND THUNDERSTORMS OVER NE WISCONSIN FOR THIS AFTERNOON. 925MB TEMPS 18C TO 20C CALL FOR HIGHS IN THE UPPER 70S TO LOWER 80S. TONIGHT...850MB MOISTURE AND INSTABILITY AXIS WILL REMAIN OVERHEAD. LLJ WILL DEVELOP OVER WESTERN WISCONSIN WITH A NOSE POINTED INTO LAKE SUPERIOR. ANY KIND OF WEAK SHORTWAVE IMPULSE COULD INITIATE CONVECTION WITH MID-LEVEL LAPSE RATES GREATER THAN 8C...BUT TOUGH TO IDENTIFY ANY FEATURES ON SATELLITE OR IN THE MODELS. IF SOMETHING WERE TO POP...WESTERN WISCONSIN LOOKS BETTER ON PAPER. BUT UNCERTAINTY IS TOO HIGH TO INCLUDE IN THE FORECAST. OTHERWISE...SOUTH FLOW WILL AGAIN SEND WAVES OF MARINE STRATUS AND FOG NORTH ALONG THE LAKESHORE AND ACROSS DOOR COUNTY AND FAR NE WISCONSIN. A WARM NIGHT AHEAD WITH LOWS IN THE MID TO UPPER 50S. SUNDAY...SHORTWAVE ENERGY WILL PASS SOUTH OF THE AREA WHILE MID-LEVEL HEIGHTS BUILD OVERHEAD. AS A RESULT...SEEING STRONGER CAPPING ON PROGGED SOUNDINGS WHICH SHOULD KEEP A LID ON SHOWER AND THUNDERSTORM DEVELOPMENT. WILL GO DRY ONCE AGAIN. HIGHS AGAIN IN THE UPPER 70S TO LOWER 80S...BUT COOLER NEAR LAKE MICHIGAN WHERE THE ONSHORE COMPONENT WILL BE A LITTLE STRONGER. .LONG TERM...SUNDAY NIGHT THRU FRIDAY. MAIN FORECAST CHALLENGES ARE TEMPS...PRECIP CHANCES...AND FOG POTENTIAL. SUMMER-LIKE PATTERN CONTINUES INTO EARLY NEXT WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN U.S. AND SOUTHERLY FLOW USHERS IN WARM AIR AND RELATIVELY HIGH DEWPOINTS. TROUGH ACROSS THE WESTERN U.S. WILL CROSS INTO THE PLAINS ON WEDNESDAY...AND TRANSITION INTO A CUT OFF LOW THAT SLOWLY MOVES SOUTH OF THE GREAT LAKES LATE NEXT WEEK. MODELS DISAGREE ON THE EVOLUTION FROM A LONGWAVE TROUGH TO A CUT OFF LOW...BOTH WITH LOCATION AND TIMING...BRINGING PLENTY OF UNCERTAINTY INTO THE FORECAST. IN GENERAL...PLAN TO FOLLOW A GFS/ECMWF BLEND. SUNDAY NIGHT IS STILL LOOKING DRY...AS THE AREA REMAINS UNDER UPPER RIDGING AND NO OBVIOUS TRIGGER FOR CONVECTION. CANNOT TOTALLY RULE OUT A STRAY SHOWER OR STORM AS STEEP LAPSE RATES REMAIN OVER THE AREA...BUT PREFER TO STAY WITH A DRY FORECAST. CLOUDS WILL BE ON THE INCREASE OVERNIGHT AND ON MONDAY MORNING THOUGH...AS MOISTURE INCREASES ALOFT. WILL START TO INCREASE POPS ON MONDAY AND MONDAY NIGHT OVER THE AREA AS UPPER TROUGH AND SHORTWAVE ENERGY APPROACH THE AREA. STILL BELIEVE THE MAJORITY OF THE ACTIVITY WILL STAY TO OUR WEST...WHERE THE BETTER MOISTURE/FORCING AND BAROCLINIC ZONE IS LOCATED...BUT WILL CARRY LOW CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL WI...WITH SLIGHT CHANCE POPS BUFFERING THIS AREA TO THE EAST. THE EXTENDED DRY SPELL (AT LEAST FOR MOST LOCATIONS) WILL COME TO AN END TUESDAY OR WEDNESDAY...AS THE UPPER TROUGH AND A NORTHERN PLAINS SHORTWAVE CONVERGE ON THE AREA. POPS WILL NEED TO BE ADJUSTED FOR TUESDAY AS THE TIMING IS PINNED DOWN...BUT PLAN TO STICK WITH CHANCE POPS WEST AND SLIGHTS EAST TO COVER FOR NOW. HIGHEST POPS WILL BE PLACED ON WEDNESDAY...AS THERE IS ENOUGH MODEL CONSENSUS SHOWING PRECIP OVER THE AREA. THE UNSETTLED WEATHER LOOKS TO CONTINUE INTO THE END OF THE WEEK AS THE UPPER LOW DRIFTS SOUTH OF THE AREA...HOWEVER CONFIDENCE IS LOW ON THE OVERALL PATTERN. WITH MODELS DIFFERING ON THE TIMING AND LOCATION OF THE CUT OFF LOW...AS WELL AS A POSSIBLE SHORTWAVE OVER THE NORTHERN PLAINS...IT WILL BE HARD TO SAY WITH CONFIDENCE WHERE THE BEST CHANCES FOR PRECIP RESIDE AND WHEN TO GO DRY. HAVE LOW CHANCE AND SLIGHT POPS TO COVER THIS UNCERTAINTY. DOWNPLAYED THUNDER POTENTIAL FOR MANY OF THE PERIODS...ESPECIALLY AT NIGHT...AS CONVECTIVE PARAMETERS ARE NOT OVERLY IMPRESSIVE. AS FOR FOG...WILL CONTINUE TO HIGHLIGHT ON LAKE MICHIGAN AND MUCH OF THE BAY THROUGH MID-WEEK AS UNSEASONABLY HIGH DEWPOINTS TRAVEL ACROSS THE RELATIVELY COOLER WATERS. WILL ALSO MENTION FOG ALONG THE IMMEDIATE SHORELINE AS ANY FOG BANK THAT DEVELOPS COULD DRIFT INLAND. WITH DEWPOINTS IN THE 50S TO NEAR 60 THROUGH MID- WEEK...DO EXPECT PATCHY FOG ELSEWHERE SOME NIGHTS IF WINDS CAN DECOUPLE AND SKIES ARE CLEAR. BEST CHANCE FOR THIS WILL BE SUNDAY NIGHT...SO WILL CONTINUE TO MENTION FOG ACROSS THE ENTIRE CWA. WINDS LOOK TO STAY UP THE REST OF THE NIGHTS TO KEEP THE THREAT OF FOG LOW. RECORD OR NEAR RECORD WARMTH WILL CONTINUE ON MONDAY AND TUESDAY AS PERSISTENT SOUTHERLY FLOW CONTINUES TO USHER IN WELL ABOVE NORMAL TEMPS. TUESDAY LOOKS TO BE THE LAST DAY IN THE 70S FOR PORTIONS OF CENTRAL AND EAST-CENTRAL WISCONSIN...BEFORE THE CLOUDS AND PRECIP HOLD TEMPS IN THE MID/UPPER 50S NORTH AND LOW 60S SOUTH FOR THE END OF THE WORK WEEK. THESE MAY BE A LITTLE GENEROUS IF PRECIP/CLOUD COVER ARE WIDESPREAD ENOUGH. ALTHOUGH TEMPS WILL BE SIGNIFICANTLY COOLER LATE IN THE WEEK COMPARED TO EARLY IN THE WEEK...THEY WILL REMAIN ABOVE NORMAL. && .AVIATION...ISOLD CONVECTION WILL BE PASSING OVER NORTHERN WISCONSIN OVERNIGHT. OTHERWISE AFTER SOME PATCHY MVFR VSBYS DUE TO FOG...MAINLY VFR CONDITIONS EXPECTED SATURDAY. TDH && .MARINE...AREAS OF DENSE MARINE FOG SEEM MOST CONCENTRATED ADJACENT TO THE DOOR PENINSULA...AND THE CENTRAL AND NORTHERN PORTIONS OF GREEN BAY. WITH COORD FROM MKX...WILL CANCEL THE MARINE DENSE FOG ADVISORY FOR AREAS SOUTH OF THE DOOR. WILL LEAVE A MENTION OF PATCHY DENSE FOG THROUGH SUNDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/BERSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 AM CDT SAT MAR 17 2012 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 310 AM CDT SAT MAR 17 2012 MAIN FORECAST CONCERNS ARE ON ANY CHANCES FOR PRECIPITATION THROUGH SUNDAY NIGHT...WINDS AND THE UNPRECEDENTED WARMTH. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING JUST OFF THE CALIFORNIA COAST WHILE BROAD RIDGING WAS BUILDING DOWNSTREAM OVER THE EASTERN TWO THIRDS OF THE U.S.. RIDGE AXIS SITS OVER THE GREAT LAKES...PLACING THE FORECAST AREA UNDER SOUTHWEST FLOW. WITHIN THIS SOUTHWEST FLOW...A WEAK SHORTWAVE COMBINED WITH A WARM FRONTAL BOUNDARY AND INCREASING LOW LEVEL JET TO PRODUCE A CLUSTER OF STRONG TO SEVERE SHOWERS AND THUNDERSTORMS LAST EVENING OVER CENTRAL WISCONSIN. THESE HAVE SINCE LIFTED INTO UPPER MICHIGAN THANKS TO THE SHORTWAVE MOVING NORTHEAST AND A 30-40 KT SOUTHWEST JET AT 850MB. WITHIN THIS SOUTHWEST FLOW...THE ONLY SHORTWAVES OF NOTE ARE WEAK ONES IN NEBRASKA...AND THESE ARE NOT PRODUCING MUCH CLOUDS AT ALL. WITH THE FORECAST AREA UNDER THAT STRONG SOUTHWEST JET AND A RELATIVELY TIGHT PRESSURE GRADIENT AT THE SURFACE AHEAD OF A TROUGH IN THE DAKOTAS... TEMPERATURES HAVE STRUGGLED TO FALL. READINGS ARE ONLY IN THE 60S. DEWPOINTS ARE ALSO STAYING UP IN THE MID TO UPPER 50S. AIRMASS IS ALSO SEMI-CAPPED AND DRY...LOOKING AT THE 00Z DVN SOUNDING. GOING FARTHER SOUTHWEST TO OAX AND IT DRIES OUT EVEN MORE. DESPITE THE DRIER AIR...THERE IS ENOUGH INSTABILITY WHEN LIFTED FROM 800MB /APPROX 700 J/KG/ TO PRODUCE PRECIPITATION. A ZONE OF 800MB SPEED CONVERGENCE IN SOUTHWEST WISCONSIN AND NORTHWEST ILLINOIS HAS PRODUCED SOME SHOWERS DOWN THERE. TODAY THROUGH SUNDAY NIGHT...UPPER TROUGHING APPROACHING THE WEST COAST OF THE U.S. RIGHT NOW IS PROGGED BY ALL MODELS TO MOVE INTO THE ROCKIES BY 12Z MONDAY. A FAIRLY DEEP LOW PRESSURE SYSTEM ENDS UP DEVELOPING OVER EASTERN MONTANA AS THIS TROUGH MOVES EAST...ALLOWING FOR STRONG SOUTHERLY FLOW TO PERSIST DOWNSTREAM INTO OUR FORECAST AREA. A COUPLE OF IMPACTS FROM THIS STRONG SOUTHERLY FLOW INCLUDE: 1. HELPING TO MAINTAIN THE UNSEASONABLY HIGH DEWPOINTS...WHICH COULD EXCEED 60F AT TIMES BETWEEN 15-18Z BEFORE DROPPING DUE TO MIXING. 2. MAINTAIN THE UNSEASONABLY WARM 925 AND 850MB TEMPS...WHICH ARE PROGGED TO STAY BETWEEN 16-20C AND 12-14C RESPECTIVELY. THESE READINGS ARE VERY SIMILAR TO WHAT WAS SEEN FRIDAY...SO HIGH TEMPERATURES BOTH TODAY AND SUNDAY ARE LIKELY TO BE SIMILAR. SOME HINTS FROM MET GUIDANCE WHICH DID WELL YESTERDAY THAT SITES SUCH AS BOSCOBEL COULD HIT THE MID 80S. GENERALLY FOLLOWED THIS. 3. A LOT OF GUSTY WINDS THROUGHOUT. APPEARS THAT WHEN LOOKING AT SOUNDINGS...MIXING DEPTHS AT MOST APPROACH 850MB. MOMENTUM TRANSFER FROM THIS LEVEL KEEPS WINDS BELOW ADVISORY CRITERIA...EVEN AT RST. 4. RESULTING FROM ITEMS 1-3 ABOVE...LOW TEMPERATURES ARE GOING TO STAY VERY WARM FOR THIS TIME OF YEAR...LIKELY STRUGGLING TO GET MUCH BELOW 60. REGARDING PRECIPITATION...TRIGGERS ARE VERY HARD TO FIND THROUGH SUNDAY NIGHT. IN ADDITION...THE AIRMASS LOOKS A LITTLE MORE CAPPED PER RUC/GFS SOUNDINGS. WE DO HAVE THE WEAK SHORTWAVES IN NEBRASKA COMING ACROSS THE FORECAST AREA AT 18Z TODAY...BUT THERE IS NO SURFACE CONVERGENT FEATURE LIKE YESTERDAY WITH THE WARM FRONT. IN FACT...NO SURFACE CONVERGENT FEATURES ARE PRESENT THROUGH SUNDAY NIGHT. AFTER 06Z SUNDAY NIGHT...THERE ARE INDICATIONS OF A SHORTWAVE COMING ACROSS SOUTHEAST MINNESOTA...AS WELL AS ISENTROPIC LIFT ON THE 305-310 K SURFACES. THE 17.00Z GFS/CANADIAN BOTH HINT AT POTENTIAL FOR SOME CONVECTION IN THIS AREA...SO INCLUDED SOME 20 PERCENT CHANCES FOR NOW...GIVEN NAM/UKMET/ECMWF DRY. FOR THE REST OF THE PERIOD...ALL MODELS ARE PRETTY MUCH DRY THROUGH SUNDAY WHICH SEEMS REASONABLE. MONDAY AND MONDAY NIGHT...THE UPPER TROUGHING OVER THE ROCKIES IS FORECAST TO INCH EASTWARD...WITH ITS AXIS FROM EASTERN MONTANA INTO NEW MEXICO AT 12Z TUESDAY. ALTHOUGH THIS TROUGH IS FAR AWAY FROM THE AREA...WE WILL SEE 10-30 METER 500MB HEIGHT FALLS EACH 12 HOUR PERIOD OVER THE FORECAST AREA...HIGHEST WEST. THESE HEIGHT FALLS COMBINED WITH STRONG MOISTURE TRANSPORT ON A SOUTHERLY 40-60 KT 850MB JET WILL YIELD INCREASING PRECIPITATION CHANCES...ESPECIALLY AGAIN OVER THE WEST. PRECIPITABLE WATER VALUES CLIMB TO 1-1.4 INCHES WHICH WOULD SUPPORT SOME DECENT PRECIPITATION TOO. CAPE VALUES ARE RESTRICTED SOMEWHAT DUE TO CLOUD COVER...PERHAPS UP TO 500 J/KG OF VERY THIN MUCAPE. THIS SHOULD LIMIT THUNDER COVERAGE TOO. DESPITE THE INCREASED CLOUD COVER AND PRECIPITATION...STILL ANTICIPATING TEMPERATURES TO RISE INTO THE 70S ON MONDAY...WARMEST EAST WHERE SOME SUN COULD OCCUR. LOWS STAY UP TOO MONDAY NIGHT WITH THE SURFACE COLD FRONT STILL WAY OFF TO THE WEST IN THE EASTERN DAKOTAS. .LONG TERM...TUESDAY THROUGH FRIDAY NIGHT 310 AM CDT SAT MAR 17 2012 LONG TERM FORECAST IS BECOMING MORE UNCERTAIN...PRIMARILY BECAUSE MODELS ARE STRUGGLING ON HOW TO HANDLE THE WESTERN U.S. TROUGH FROM MONDAY NIGHT. 17.00Z ECMWF/GFS/CANADIAN AND MOST GFS ENSEMBLES ALL SUGGEST THE TROUGH WILL CUT-OFF AS IT CROSSES THE PLAINS TUESDAY AND WEDNESDAY...BUT EXACTLY WHEN AND THEN HOW TO HANDLE THIS UPPER LOW VARIES AMONG EVERY MODEL. THERE STILL REMAINS A FEW GFS ENSEMBLES AND THE 17.00Z UKMET THAT SUGGEST THE TROUGH STAYS TOGETHER... FOLLOWING THE 16.12Z ECMWF IDEA. HOWEVER...OVER THE LAST COUPLE DAYS OF MODEL RUNS...THESE SEEM TO BE AN OUTLIER. THEREFORE PREFERENCE IS TO FOLLOW THE MAJORITY 17.00Z GUIDANCE. AS THE UPPER TROUGH APPROACHES THE FORECAST AREA TUESDAY INTO WEDNESDAY...THE MOISTURE STREAM REFERENCED IN THE MONDAY/MONDAY NIGHT DISCUSSION WILL FULLY SHIFT OVERHEAD. SEEMS LIKE TUESDAY NIGHT IS THE BEST PERIOD FOR THE ENTIRE FORECAST AREA TO SEE RAIN. MODEL GUIDANCE CONSENSUS OF 60-70 PERCENT CHANCES ARE REASONABLE...BUT MAY NEED TO BE RAISED MORE IF THIS TIME PERIOD REMAINS CONSISTENT FOR PRECIPITATION. AFTER WEDNESDAY...ATTENTION TURNS TO THE SOUTHERN END OF THE SPLITTING UPPER TROUGH WHICH TURNS INTO AN UPPER LOW. SOME MODELS SUGGEST THE UPPER LOW COULD LIFT TOWARDS THE AREA ON FRIDAY. IF SO...THEN SOME SHOWERS COULD MOVE IN. FOR NOW...HAVE LOWER 20-40 PERCENT CHANCES FOR WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...ACCOUNTING FOR THE DIMINISHING MOISTURE STREAM AND THE APPROACH OF THE UPPER LOW. REGARDING THUNDER...REDUCED THESE PROBABILITIES TO 20 AND ONLY DURING THE DAYTIME HOURS FOR TUESDAY THROUGH THURSDAY...GIVEN LESS THAN 500 J/KG OF ONLY DAYTIME INSTABILITY SUGGESTED BY THE GFS. TEMPERATURES THROUGHOUT MUCH OF THE LONG TERM PERIOD WILL STAY WELL ABOVE NORMAL...UNTIL MAYBE FRIDAY NIGHT IF THE ECMWF IS RIGHT TRYING TO SHOW SOME COLDER AIR COMING DOWN FROM CANADA. IN ANY EVENT...850MB TEMPS DROP FROM 10-12C ON TUESDAY TO 6-8C BY 12Z FRIDAY. A BLEND OF MODEL GUIDANCE SEEMED REASONABLE. && .AVIATION... 1100 PM CDT FRI MAR 16 2012 WINDS WILL STAY UP TONIGHT...WITH BUFKIT SOUNDINGS INDICATING 10 TO 15 KTS BY 100-200 FT AND LITTLE IF ANY NOCTURNAL INVERSION TO HELP LIGHTEN SFC WINDS. THE RELATIVELY MOIST AIR MASS FOR MID MARCH WILL REMAIN IN PLACE...WITH SFC TDS IN THE UPPER 50S TO AROUND 60 THROUGH THE WEEKEND. STILL...FEEL THE WINDS SHOULD MITIGATE THE FOG POTENTIAL EARLY THIS MORNING...AND WILL TREND P6SM FOR NOW. AFTERNOON INSTABILITY WITH NEARLY 300 PERCENT OF NORMAL PW IS AMPLE FUEL FOR SHRA/TS...BUT HAVING A HARD TIME FINDING A KICKER. A WARM FRONT IS WELL NORTH NOW...AND FCST SOUNDINGS SUGGEST MOST OF THE INSTABILITY IS HOUSED ABOVE A LOW/MID LEVEL INVERSION THAT HANGS THROUGH SAT-SUN. SO...THINK THE PCPN THREAT WILL BE VERY LOW UNTIL EARLY NEXT WEEK. WILL KEEP TAF PCPN FREE...BUT IF A FOCUS FOR SHRA/TS CAN BE FOUND...SOME INCLUSION IN THE TAFS MAY BE NEEDED. A TIGHT PRESSURE GRADIENT WILL HOLD ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THIS WEEKEND...AND BREEZY SOUTHERLY WINDS WILL CONTINUE. MIXING VIA BUFKIT SOUNDINGS SUGGEST AFTERNOON GUSTS UPWARDS OF 30 KTS AT KRST. && .CLIMATE...TODAY THROUGH TUESDAY 310 AM CDT SAT MAR 17 2012 RECORD HIGHS AND RECORD WARM LOWS ARE POSSIBLE THROUGH TUESDAY... ESPECIALLY THIS WEEKEND...AS AN UNSEASONABLY WARM AND MOIST AIR MASS CONTINUES TO RESIDE ACROSS THE UPPER MIDWEST. TEMPERATURES SHOULD BEGIN COOLING MON/TUE AS CLOUDS/ -SHRA INCREASE ACROSS THE AREA. HOWEVER...RECORDS ON THOSE DAYS COMPARED TO FORECASTS STILL SUGGEST SOME POTENTIAL TO BREAK THEM. && .ARX WATCHES/WARNINGS/ADVISORIES... 310 AM CDT SAT MAR 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK CLIMATE......AJ/RRS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
435 AM EDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT MUCH OF THE SAME FOR BEGINNING OF THE WEEK...WITH FORECAST ATTENTION CENTERED ON RECORD BREAKING WARMTH AND CONVECTIVE POTENTIAL. IN THE VERY NEAR TERM...HAVE ISSUED A DENSE FOG ADVISORY FOR NORTHERN NORTHWEST OHIO COUNTIES AND HILLSDALE COUNTY MICHIGAN. STRONGER RADIATIONAL COOLING ACROSS THESE LOCATIONS EARLIER...COMBINED WITH WEAK EAST SOUTHEAST LOW LEVEL FLOW COMPONENT HAS BEEN CONDUCIVE FOR SOME WESTWARD EXPANSION OF DENSE FOG THAT FORMED WEST OF LAKE ERIE. THIS DENSE FOG MAY NOT MAKE IT AS FAR WEST AS THE FAR WESTERN PORTIONS OF THE COUNTIES IN THE DENSE FOG ADVISORY BUT FOG SATELLITE PRODUCT AND OBSERVATIONS SUGGEST A SLOW WESTWARD EXPANSION OF DENSE FOG OVERNIGHT. THE SLOW MOVING CONVECTIVELY ENHANCED VORT MAX THAT BROUGHT YESTERDAYS PRECIPITATION HAS EXITED INTO EASTERN OHIO THIS MORNING. SOME ISOLATED SHOWERS TRYING TO DEVELOP IN NARROW AXIS OF ENHANCED LOW/MID LEVEL WARM ADVECTION BEHIND THIS DEPARTING VORT MAX FROM SOUTH CENTRAL LOWER MICHIGAN INTO NORTHWEST OHIO. RUC INITIALIZATION SOUNDINGS SUGGEST THESE SHOWERS ARE ELEVATED TO AN EXTENT MAKING IT DIFFICULT TO REALIZE MUCH ELEVATED INSTABILITY. SIMILAR CONCERNS IN TERMS OF MAGNITUDE OF ELEVATED INSTABILITY PERSIST ACROSS WESTERN PORTIONS OF THE AREA...ALTHOUGH SHORT TERM PROGS FROM NAM/RUC SUGGEST WEAK AREA OF SECONDARY LOW LEVEL MOISTURE/THETAE ADVECTION SHIFTING INTO NORTHWEST INDIANA THIS MORNING THAT MAY HELP TO ENHANCE ELEVATED INSTABILITY. A WEAK SHEARED VORT MAX ALSO LIFTING NORTHEASTWARD DOWNSTREAM OF LARGE SCALE WESTERN CONUS TROUGH MAY ALSO PROVIDE SOME WEAK MID/UPPER LEVEL SUPPORT TO GENERATE SOME ISOLD ELEVATED STORMS OVER THE NEXT FEW HOURS. A BETTER CHANCE OF THUNDERSTORMS EXISTS THIS AFTERNOON AND HAVE MADE NO CHANGES TO TSRA CHANCE POPS WEST/SLIGHT CHANCE EAST AS CONTINUED WEAK EMBEDDED WAVES LIFT INTO THE AREA. THE MOST NOTABLE OF THESE SHORT WAVES APPEARS TO BE SITUATED FROM EASTERN MISSOURI INTO NORTHERN ARKANSAS EARLY THIS MORNING. MID LEVEL LAPSE RATES ARE EXPECTED TO STEEPEN TOWARD MIDDAY AS AN ELEVATED MIXED LAYER ADVECTS NORTHEAST INTO THE AREA. SFC TEMPERATURES WARMING TO AROUND 80 THIS AFTERNOON SHOULD COMBINE WITH THESE STEEPER MID LEVEL LAPSE RATES FOR SBCAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. PRESENCE OF MID LEVEL RIDGE/LOW SHEAR WILL KEEP SEVERE THREAT LOW...WITH PERHAPS SLIGHTLY MORE RESPECTABLE 0 TO 6 KM BULK SHEAR VALUES INTO THE 20 TO 25 KNOT RANGE ACROSS WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. WILL MENTION JUST AN ISOLD HAIL/WIND THREAT IN THIS MORNINGS HWO. IN TERMS OF TEMPERATURES...MIXING TO AROUND 900 HPA SHOULD SUPPORT HIGHS FROM THE UPPER 70S TO AROUND 80 WHICH WOULD ONCE AGAIN BREAK THE RECORD HIGHS FOR THE DATE...76 AT FORT WAYNE AND 77 AT SOUTH BEND...BOTH SET IN 1921. UPPER LEVEL TROUGH DIGGING/AMPLIFICATION ACROSS THE ROCKIES WILL RESULT IN DOWNSTREAM MID LEVEL HEIGHT RISES ACROSS THE GREAT LAKES REGION TONIGHT/TUESDAY. MODEL GUIDANCE IS ALSO IN REASONABLE AGREEMENT IN A DRIER POCKET OF LOW LEVEL AIR ADVECTING NORTHWARD LATER TONIGHT AS THIS RIDGE AMPLIFIES...EFFECTIVELY SUPPRESSING ELEVATED CONVECTION. THUS...WILL KEEP FORECAST DRY TONIGHT. TUESDAY SHAPING UP TO BE ANOTHER DAY OF RECORD BREAKING WARMTH WITH DEEPER MIXING THAN MONDAY...THAT SHOULD SUPPORT HIGHS IN THE LOWER 80S MOST LOCATIONS. THIS DEEPER MIXING AND SLIGHTLY DRIER LOW LEVEL AIR SHOULD LIMIT DIURNAL INSTABILITY...AND WITH LARGE SCALE RIDGE IN PLACE...WILL KEEP REMAINDER OF SHORT TERM DRY. && .LONG TERM... / WEDNESDAY THROUGH SUNDAY / TREND IN MODEL GUIDANCE HAS BEEN TO SLOW THE EASTERN PROGRESSION OF A SOUTHERN PLAINS CUT-OFF UPPER LOW LATE THIS WEEK INTO SATURDAY. THIS IS NOT SURPRISING GIVEN THE NATURE OF CUT-OFFS AND EXPECTED AMPLIFICATION OF A HIGHLY ANOMALOUS EASTERN CONUS UPPER RIDGE. AS A RESULT OPTED TO BUY INTO THIS SLOWER SOLUTION WITH THIS DEEP TROPOSPHERIC CIRCULATION NOW PROGGED TO DRIFT TO THE MID MS VALLEY BY FRIDAY...AND THE OH VALLEY BY SATURDAY. RAISED HIGHS SEVERAL DEGREES...ESPECIALLY THURSDAY AND FRIDAY GIVEN THE SLOWER SOLUTION. A COOL DOWN IN STILL IN THE WORKS FRIDAY INTO THIS WEEKEND PER HEIGHT FALLS AND INCREASING CLOUDS/RAIN?...STILL LIKELY REMAINING AROUND 10 DEGREES OR SO ABOVE NORMAL BY THIS WEEKEND (COMPARED TO EXPECTED RECORD HIGH TEMPS AROUND 30 DEGREES ABOVE NORMAL TO START THE PERIOD). SYSTEM WILL MATURE AND FILL A BIT WITH EWD DRIFT AS IT COLLIDES WITH THE RIDGE...GETTING ITS KICK FROM ANOTHER LONGWAVE TROUGH PROGGED TO DIG TOWARDS THE WEST COAST. GIVEN THIS EXPECT FORCING TO WEAKEN A BIT AS IT FINALLY MAKES ITS WAY INTO THE OH VALLEY AND SRN GREAT LAKES. HOWEVER...THERE STILL SHOULD BE A MORE ORGANIZED BAND OF SHOWERS TO ACCOMPANY THE WEAKENING LOW LEVEL BAROCLINIC ZONE/OCCLUDED FRONT...WITH A MODEL CONSENSUS FAVORING THE FRIDAY-FRIDAY NIGHT PERIOD FOR MEASURABLE RAINFALL LOCALLY. RAINFALL AMOUNTS ARE NOT LOOKING OVERLY IMPRESSIVE ALTHOUGH SOME LOCALIZED HEAVIER RAIN APPEARS POSSIBLE GIVEN SUFFICIENT MOISTURE/WEAK INSTABILITY. CHANCES FOR SHOWERS LINGER INTO SATURDAY AS THE UPPER LOW AND ASSOCIATED COLD POOL ALOFT SHIFTS INTO REGION. OVERALL... CHANGES TO POPS/WX WERE TO REMOVE LOWER CHC POPS WEDNESDAY NIGHT AND LOWER THURSDAY POPS TO SLIGHT CHC. ONLY MINOR TWEAKS OTHERWISE. && .AVIATION... 06Z TAFS...OVERALL VERY FEW CHANGES TO THE 06Z TAFS FROM PREVIOUS ISSUANCE WITH CONTINUED CONCERNS CENTERED ON FOG AND CONVECTIVE POTENTIAL. IN TERMS OF CONVECTION...RUC INITIALIZATION SOUNDINGS SUGGEST MODERATE AMOUNTS OF ELEVATED INSTABILITY ACROSS MUCH OF NORTHERN INDIANA...BUT QUESTION CONTINUES TO BE IF ENOUGH ELEVATED LOW LEVEL MOISTURE WILL BE PRESENT TO OVERCOME ANY CONVECTIVE INHIBITION. AN UPPER LEVEL SHORT WAVE ACROSS CENTRAL ILLINOIS WILL LIFT INTO NORTHERN INDIANA THROUGH 09Z...AND WILL HAVE TO WATCH FOR SOME ISOLATED CELLS DEVELOPING ACROSS EAST CENTRAL ILLINOIS/NORTH CENTRAL INDIANA OVER NEXT 2 TO 4 HOUR PERIOD. WITH LOW CONFIDENCE IN THIS SCENARIO...HAVE KEPT TAFS DRY WITH JUST A CB CLOUD GROUP MENTION FROM 10Z-15Z AT KSBN. ADDITIONAL WEAK DISTURBANCES TO EJECT NORTHEAST INTO THE NORTHERN INDIANA ON MONDAY WITH MODERATE INSTABILITY DEVELOPING AGAIN DURING THE AFTERNOON. WILL KEEP TAFS DRY THROUGH THE AFTERNOON AT THIS FORECAST DISTANCE GIVEN EXPECTED LIMITED COVERAGE. FOG ALSO WILL NEED TO BE MONITORED TONIGHT...BUT PRESENT INDICATIONS SUGGEST MOST SIGNIFICANT FOG TO AFFECT AREAS ACROSS EXTREME NORTHEAST INDIANA/SOUTHEAST LOWER MICHIGAN. THUS...HAVE KEPT MVFR VSBYS IN FOG FOR BOTH KSBN AND KFWA IN THE 10-14Z TIMEFRAME. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MIZ081. OH...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR OHZ001-002- 004-005. LM...NONE. && $$ SHORT TERM...MARSILI LONG TERM...STEINWEDEL AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
238 AM CDT MON MAR 19 2012 ...UPDATED FOR EXTENDED DISCUSSION... .UPDATE... ISSUED AT 1123 PM CDT SUN MAR 18 2012 HAVE UPDATED POPS AND WEATHER THROUGH THE OVERNIGHT TO ACCOUNT FOR EXPECTED PRECIPITATION TREND. THE HRRR HAS A DECENT TREND ON POPS EVOLUTION. A NARROW LINE OF THUNDERSTORMS ARE RAPIDLY DEVELOPING ALONG THE COLD FRONT SPREADING ACROSS THE TEXAS PANHANDLE NORTHEASTWARD FROM AMARILLO. THE LINE SHOULD GROW UPSCALE INTO THE NOW WEAKENING INSTABILITY FIELD OVER CENTRAL KANSAS THROUGH THE OVERNIGHT. THE ARW AND NMM NAM/WRF RUNS ARE SUPPORTIVE OF SUCH AN EVOLUTION WITH SOME DIFFERENCES IN PLACEMENT. THE NAM SURFACE WIND FIELD INDICATES WINDS SHOULD VEER AND WEAKEN IN THE COMING HOURS AS THE SURFACE TROUGH OVER EASTERN COLORADO MOVES EAST. AT THIS TIME ONLY A COUPLE OF METAR OBSERVATIONS ARE CLOSE TO OR MEETING WIND ADVISORY CRITERIA. WE PLAN TO ALLOW THE CURRENT WIND ADVISORY TO EXPIRE AT MIDNIGHT. UPDATE ISSUED AT 640 PM CDT SUN MAR 18 2012 WILL GO AHEAD AND LET THE RED FLAG WARNING FOR MORTON AND STANTON COUNTY EXPIRE ON TIME AT 7 PM CDT. HUMIDITIES ARE RISING ABOVE 15 PERCENT. A FEW THUNDERSTORMS WERE FORMING ALONG THE DRYLINE AND MOVING NORTH NORTHEAST AT AROUND 45 MPH FROM GARDEN CITY TO SCOTT CITY. SOME STORM SPLITTING WAS OCCURRING BUT UPDRAFTS SO FAR HAVE NOT BEEN ABLE TO SUSTAIN THEMSELVES LONG ENOUGH FOR SEVERE THRESHOLDS. AS THE SUN SETS THE PROBABILITY FOR SEVERE THUNDERSTORMS WILL DECREASE. HOWEVER LATER TONIGHT AROUND OR AFTER MIDNIGHT AS THE UPPER TROUGH AND COLD POOL ALOFT MOVES INTO WESTERN KANSAS A MARGINALLY SEVERE MCS MAY FORM WITH HAIL LESS THAN OR UP TO DIME AND QUARTER SIZE. A LOW LEVEL JET OF 60 KTS WILL CONTINUE WITH STRONG SURFACE WINDS THROUGH AROUND MIDNIGHT. THERE MAY BE A BRIEF LULL IN THE STRONG WINDS AROUND SUNSET THEN THEY SHOULD PICK BACK UP AGAIN. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 325 PM CDT SUN MAR 18 2012 A DEEP UPPER-LEVEL TROUGH WAS MOVING TROUGH THE INTERMOUNTAIN WEST THIS AFTERNOON. AHEAD OF THIS FEATURE, STRONG LEE TROUGHING WAS OCCURRING ALONG THE HIGH PLAINS. A SURFACE DRYLINE WAS LOCATED ACROSS FAR WESTERN KANSAS. TO THE EAST OF THE DRYLINE, LOW LEVEL MOISTURE WAS IN PLACE AND CAPPING WAS BEING ERODED THROUGH STRONG DAYTIME HEATING. HOWEVER, A STRONG CAP WAS STILL IN PLACE WELL AHEAD OF THE DRYLINE AT DODGE CITY PER MODEL SOUNDINGS. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE DRYLINE BY 5 PM WITH INTENSE DAYTIME HEATING. GIVEN THE STRONG SHEAR AND CAPE AROUND 2000 J/KG, LARGE HAIL WILL ACCOMPANY THE STRONGEST STORMS. DURING THE EVENING HOURS AS THE LOWER LEVELS COOL, CLOUD HEIGHTS WILL DECREASE AS THE STORMS MOVE EAST OF THE DRYLINE. THEREFORE, A TORNADO OR TWO CAN`T BE RULED OUT DURING THE EVENING BEFORE THE LOWER LEVELS STABILIZE TOO MUCH AND SURFACE BASED STORMS DIMINISH. LATER TONIGHT, MID-LEVEL COOLING ASSOCIATED WITH THE UPPER-LEVEL SYSTEM WILL APPROACH, ALONG WITH A NORTH TO SOUTH ORIENTED COLD FRONT. SO ADDITIONAL THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT, ESPECIALLY OVER SOUTH CENTRAL KANSAS WHERE THE DEEPEST MOISTURE WILL RESIDE. THESE STORMS SHOULD NOT BE AS SEVERE SINCE THE LOWER TO MID-LEVEL WINDS WILL BE UNIDIRECTIONAL BY THAT TIME, ALONG WITH MUCH LOWER CAPE VALUES DUE TO THE LOSS OF DAYTIME HEATING. NEVERTHELESS, MARGINALLY SEVERE HAIL IS POSSIBLE. WARM OVERNIGHT LOWS IN THE LOWER 60S CAN BE EXPECTED AROUND MEDICINE LODGE AND PRATT WHERE 60F DEWPOINTS AND 15KT WINDS WILL BE LOCATED. COOLER TEMPERATURES IN THE 40S CAN BE EXPECTED IN FAR WESTERN KANSAS IN THE DRIER AIR. CLEARING CAN BE EXPECTED ON MONDAY AS THE COLD FRONT SWEEPS ACROSS SOUTHWEST KANSAS IN THE MORNING. DESPITE THE FRONTAL PASSAGE, TEMPERATURES WILL NOT BE ALL THAT COLD SINCE THIS IS NOT AN ARCTIC AIRMASS AND SINCE SURFACE WINDS WILL HAVE A DOWNSLOPE COMPONENT. THE COOLEST TEMPERATURES SHOULD BE ALONG THE COLORADO BORDER ON THE HIGHER TERRAIN, WITH WARMER TEMPERATURES IN CENTRAL KANSAS WHERE DOWNSLOPE WARMING WILL BE GREATER. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 232 AM CDT MON MAR 19 2012 SHORT DISCUSSION TODAY DUE TO ACTIVE RADAR WATCH. LOADED THE CREXTENDFCST_INIT TOOL, CHECKED FOR INTERSITE COORDINATION COMPLIANCE AND RAN THE INTEGRITY TOOL. ALL GRIDS LOOK FINE, REASONABLE AND IN LINE WITH OTHER OFFICES. THE UPPER LEVEL CUT OFF LOW WILL TRACK INTO CENTRAL KANSAS WEDNESDAY INTO THURSDAY. AS IT DOES, DEEP MOISTURE WILL BE TRANSPORTED INTO WESTERN KANSAS ON THE NORTH AND NORTHWEST SIDE OF THE LOW. THEREFORE, POPS HAVE INCREASED TO 40 PERCENT WEDNESDAY ACROSS OUR SOUTHEAST, BUMP UP TO 60 LIKELY POPS WEDNESDAY NIGHT IN OUR EAST AND 40 TO 50 POPS IN OUR WEST, THEN DECREASE TO 40 POPS ON THURSDAY. QPF FROM THE HPC GIVES OUR SOUTHEAST AND CENTRAL ZONES 0.35-0.40 INCH THROUGH THE EVENT, AND OUR SOUTHWEST ZONES 0.30-0.35 INCH, THE NORTH WILL SEE LESS THAN THAN, PERHAPS 0.10 TO 0.15 INCH. NO POPS AFTER FRIDAY AS AN UPPER RIDGE WILL BUILD IN FROM THE SOUTHWEST AND DRY THINGS OUT. TEMPERATURES WILL BE MODERATE TO SEASONAL TUESDAY THROUGH THURSDAY, WITH HIGHS IN AROUND 60 DEGREES. FRIDAY WILL START A WARMING TREND WITH MOSTLY SUNNY SKIES AND WARMING AFFECT FROM THE HIGH PRESSURE RIDGE. MAX TEMPS WILL BE IN THE MID TO UPPER 60S FRIDAY, WARMING TO THE MID TO UPPER 70S BY SUNDAY. MIN TEMPERATURES DID NOT CHANGE, BEING THE COLDEST WEDNESDAY MORNING IN THE UPPER 20S WEST RANGING TO NEAR 41F DEGREES IN THE SOUTHEAST. THURSDAY, FRIDAY AND SATURDAY WILL SEE LOWS IN THE UPPER 30SS WEST TO THE MID 40S EAST, THEN SUNDAY SHOULD WARM MIN TEMPERATURES INTO THE MID TO UPPER 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1248 AM CDT MON MAR 19 2012 88D COMPOSITE REFLECTIVITY SHOWS A SHARP LINE OF THUNDERSTORMS MOVING EASTWARD ACROSS THE TEXAS PANHANDLE THIS MORNING. THE MODELS DEVELOP THIS LINE UPSCALE INTO PARTS OF SOUTHWEST AND CENTRAL KANSAS THROUGH THE EARLY MORNING. THE SITE WITH THE GREATEST ODDS OF RECEIVING SOME SMALL HAIL WOULD BE KDDC, BUT TEMPO TSRA CANNOT BE RULED OUT AT EITHER GARDEN CITY OR HAYS THROUGH 12 TO 15 UTC. && .FIRE WEATHER... ISSUED AT 640 PM CDT SUN MAR 18 2012 CRITICAL FIRE WEATHER CONDITIONS MAY DEVELOP MONDAY AFTERNOON FROM GARDEN CITY AND LIBERAL WESTWARD. HOWEVER, SURFACE WINDS WILL BE MARGINAL. NO WATCH OR WARNING WAS ISSUED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 39 59 36 / 60 10 10 10 GCK 63 34 56 34 / 10 10 10 10 EHA 59 33 53 32 / 10 0 10 10 LBL 63 33 57 34 / 10 0 10 10 HYS 71 41 59 37 / 50 10 10 10 P28 69 46 61 41 / 60 10 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...RUSSELL SHORT TERM...FINCH LONG TERM....BURKE AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1250 AM CDT MON MAR 19 2012 ...UPDATED FOR AVIATION... .UPDATE... ISSUED AT 1123 PM CDT SUN MAR 18 2012 HAVE UPDATED POPS AND WEATHER THROUGH THE OVERNIGHT TO ACCOUNT FOR EXPECTED PRECIPITATION TREND. THE HRRR HAS A DECENT TREND ON POPS EVOLUTION. A NARROW LINE OF THUNDERSTORMS ARE RAPIDLY DEVELOPING ALONG THE COLD FRONT SPREADING ACROSS THE TEXAS PANHANDLE NORTHEASTWARD FROM AMARILLO. THE LINE SHOULD GROW UPSCALE INTO THE NOW WEAKENING INSTABILITY FIELD OVER CENTRAL KANSAS THROUGH THE OVERNIGHT. THE ARW AND NMM NAM/WRF RUNS ARE SUPPORTIVE OF SUCH AN EVOLUTION WITH SOME DIFFERENCES IN PLACEMENT. THE NAM SURFACE WIND FIELD INDICATES WINDS SHOULD VEER AND WEAKEN IN THE COMING HOURS AS THE SURFACE TROUGH OVER EASTERN COLORADO MOVES EAST. AT THIS TIME ONLY A COUPLE OF METAR OBSERVATIONS ARE CLOSE TO OR MEETING WIND ADVISORY CRITERIA. WE PLAN TO ALLOW THE CURRENT WIND ADVISORY TO EXPIRE AT MIDNIGHT. UPDATE ISSUED AT 640 PM CDT SUN MAR 18 2012 WILL GO AHEAD AND LET THE RED FLAG WARNING FOR MORTON AND STANTON COUNTY EXPIRE ON TIME AT 7 PM CDT. HUMIDITIES ARE RISING ABOVE 15 PERCENT. A FEW THUNDERSTORMS WERE FORMING ALONG THE DRYLINE AND MOVING NORTH NORTHEAST AT AROUND 45 MPH FROM GARDEN CITY TO SCOTT CITY. SOME STORM SPLITTING WAS OCCURRING BUT UPDRAFTS SO FAR HAVE NOT BEEN ABLE TO SUSTAIN THEMSELVES LONG ENOUGH FOR SEVERE THRESHOLDS. AS THE SUN SETS THE PROBABILITY FOR SEVERE THUNDERSTORMS WILL DECREASE. HOWEVER LATER TONIGHT AROUND OR AFTER MIDNIGHT AS THE UPPER TROUGH AND COLD POOL ALOFT MOVES INTO WESTERN KANSAS A MARGINALLY SEVERE MCS MAY FORM WITH HAIL LESS THAN OR UP TO DIME AND QUARTER SIZE. A LOW LEVEL JET OF 60 KTS WILL CONTINUE WITH STRONG SURFACE WINDS THROUGH AROUND MIDNIGHT. THERE MAY BE A BRIEF LULL IN THE STRONG WINDS AROUND SUNSET THEN THEY SHOULD PICK BACK UP AGAIN. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 325 PM CDT SUN MAR 18 2012 A DEEP UPPER-LEVEL TROUGH WAS MOVING TROUGH THE INTERMOUNTAIN WEST THIS AFTERNOON. AHEAD OF THIS FEATURE, STRONG LEE TROUGHING WAS OCCURRING ALONG THE HIGH PLAINS. A SURFACE DRYLINE WAS LOCATED ACROSS FAR WESTERN KANSAS. TO THE EAST OF THE DRYLINE, LOW LEVEL MOISTURE WAS IN PLACE AND CAPPING WAS BEING ERODED THROUGH STRONG DAYTIME HEATING. HOWEVER, A STRONG CAP WAS STILL IN PLACE WELL AHEAD OF THE DRYLINE AT DODGE CITY PER MODEL SOUNDINGS. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE DRYLINE BY 5 PM WITH INTENSE DAYTIME HEATING. GIVEN THE STRONG SHEAR AND CAPE AROUND 2000 J/KG, LARGE HAIL WILL ACCOMPANY THE STRONGEST STORMS. DURING THE EVENING HOURS AS THE LOWER LEVELS COOL, CLOUD HEIGHTS WILL DECREASE AS THE STORMS MOVE EAST OF THE DRYLINE. THEREFORE, A TORNADO OR TWO CAN`T BE RULED OUT DURING THE EVENING BEFORE THE LOWER LEVELS STABILIZE TOO MUCH AND SURFACE BASED STORMS DIMINISH. LATER TONIGHT, MID-LEVEL COOLING ASSOCIATED WITH THE UPPER-LEVEL SYSTEM WILL APPROACH, ALONG WITH A NORTH TO SOUTH ORIENTED COLD FRONT. SO ADDITIONAL THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT, ESPECIALLY OVER SOUTH CENTRAL KANSAS WHERE THE DEEPEST MOISTURE WILL RESIDE. THESE STORMS SHOULD NOT BE AS SEVERE SINCE THE LOWER TO MID-LEVEL WINDS WILL BE UNIDIRECTIONAL BY THAT TIME, ALONG WITH MUCH LOWER CAPE VALUES DUE TO THE LOSS OF DAYTIME HEATING. NEVERTHELESS, MARGINALLY SEVERE HAIL IS POSSIBLE. WARM OVERNIGHT LOWS IN THE LOWER 60S CAN BE EXPECTED AROUND MEDICINE LODGE AND PRATT WHERE 60F DEWPOINTS AND 15KT WINDS WILL BE LOCATED. COOLER TEMPERATURES IN THE 40S CAN BE EXPECTED IN FAR WESTERN KANSAS IN THE DRIER AIR. CLEARING CAN BE EXPECTED ON MONDAY AS THE COLD FRONT SWEEPS ACROSS SOUTHWEST KANSAS IN THE MORNING. DESPITE THE FRONTAL PASSAGE, TEMPERATURES WILL NOT BE ALL THAT COLD SINCE THIS IS NOT AN ARCTIC AIRMASS AND SINCE SURFACE WINDS WILL HAVE A DOWNSLOPE COMPONENT. THE COOLEST TEMPERATURES SHOULD BE ALONG THE COLORADO BORDER ON THE HIGHER TERRAIN, WITH WARMER TEMPERATURES IN CENTRAL KANSAS WHERE DOWNSLOPE WARMING WILL BE GREATER. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 305 AM CDT SUN MAR 18 2012 THE LATEST MODEL RUNS OF THE ECMWF, GFS AND GEM ALL SHOW THE LARGE SCALE UPPER LEVEL TROUGH EXTENDING FROM CENTRAL WYOMING SOUTH TO NORTHERN ARIZONA BY 12Z MONDAY. STRONG UPPER LEVEL DYNAMICS WILL BE FLOWING THROUGH CENTRAL KANSAS, AND A COLD FRONT WILL BE DIVIDING OUR CWA FROM WEST TO EAST. MOISTURE WILL BE HIGH IN OUR EXTREME EASTERN COUNTIES, AND THERE WILL CONTINUE TO BE A GOOD CHANCE FOR THUNDERSTORMS ACROSS OUR EASTERN 2 TIER OF COUNTIES. THE PRECIPITATION SHOULD MOVE EAST OF OUR AREA BY 00Z TUESDAY, SO MONDAY NIGHT AND TUESDAY WILL NOT HAVE POPS IN. BY TUESDAY NIGHT, AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CUT OFF AND BE CENTERED OVER NORTH CENTRAL OKLAHOMA. THIS COULD BRING SOME WRAP AROUND RAIN SHOWERS TO OUR SOUTHEAST ZONES BOTH TUESDAY NIGHT AND WEDNESDAY. THE MOISTURE WILL GET DEEPER BY THURSDAY, SO THE NEW CR_EXTD_INIT OR CONSALL MODELS SHOW THURSDAY WITH 20 PERCENT CHANCES FOR SHOWERS, AS FAR WEST AS STANTON AND SCOTT COUNTIES. WENT ON THE LOWER SIDE FOR QPF AMOUNTS THURSDAY, AS THE SHOWERS WILL PROBABLY BE WIDELY SCATTERED AND HIGH BASED/ELEVATED. THE LARGE CUT OFF UPPER LOW PRESSURE WILL ADVANCE EAST THURSDAY NIGHT, BRINGING AN END TO THE PRECIP CHANCES. A RATHER LARGE SCALE UPPER LEVEL HIGH PRESSURE RIDGE WILL BUILD IN INTO THE WESTERN PLAINS FROM FRIDAY INTO SATURDAY. THIS WILL MEAN A WARMING TREND SETTING IN. MONDAY HIGHS WILL RANGE FROM THE MID 50S IN OUR SOUTHWEST TO THE UPPER 60S IN OUR SOUTHEAST. TUESDAY MAY BE THE COLDEST DAY IN THE EXTENDED PERIOD, WITH HIGHS ONLY IN THE LOWER 50S IN OUR WEST AND THE LOWER 60S ACROSS OUR SOUTHEAST COUNTIES. SO TECHNICALLY, THE WARMING TREND WILL BEGIN WEDNESDAY WHEN MAX TEMPS RISE TO THE LOWER 60S. MAXIMUM TEMPERATURES SHOULD WARM TO THE MID 60S BY THURSDAY, THE UPPER 60S TO LOWER 70S BY FRIDAY, AND THEN WITH THE UPPER LEVEL HIGH PRESSURE RIDGE IN FULL FORCE BY THE WEEKEND, HIGHS SATURDAY WILL TOP OUT IN THE 70F TO 75F DEGREE RANGE. MINIMUM TEMPERATURES THROUGH THE EXTENDED PERIOD WILL GO THROUGH A WIDE RANGE. TUESDAY MORNING WILL SEE THE INITIAL SURGE OF COLD AIR SNEAK INTO OUR WESTERN 1/3RD OF THE CWA, WITH MINS IN THE LOWER TO MID 30S. EASTERN COUNTIES TUESDAY WILL SEE ELEVATED MINS IN THE LOWER TO MID 40S DUE TO THE MOIST SOIL CONDITIONS. WEDNESDAY MORNING WILL LIKELY BE THE COLDEST MORNING AS COLDER AIR SEEPS EASTWARD, WITH MIN TEMPERATURES IN THE UPPER 20S IN OUR FAR WEST AND RANGING TO NEAR 40F DEGREES IN THE MEDICINE LODGE AREA. BY THURSDAY MORNING, SOME WRAP AROUND MOISTURE WILL BE FILTERING IN, AND LOWS WILL RANGE FROM 37F DEGREES IN HAMILTON COUNTY TO 44F DEGREES IN BARBER COUNTY. FRIDAY AND SATURDAY WILL SEE MORNING LOW TEMPERATURES IN THE LOWER 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1248 AM CDT MON MAR 19 2012 88D COMPOSITE REFLECTIVITY SHOWS A SHARP LINE OF THUNDERSTORMS MOVING EASTWARD ACROSS THE TEXAS PANHANDLE THIS MORNING. THE MODELS DEVELOP THIS LINE UPSCALE INTO PARTS OF SOUTHWEST AND CENTRAL KANSAS THROUGH THE EARLY MORNING. THE SITE WITH THE GREATEST ODDS OF RECEIVING SOME SMALL HAIL WOULD BE KDDC, BUT TEMPO TSRA CANNOT BE RULED OUT AT EITHER GARDEN CITY OR HAYS THROUGH 12 TO 15 UTC. && .FIRE WEATHER... ISSUED AT 640 PM CDT SUN MAR 18 2012 CRITICAL FIRE WEATHER CONDITIONS MAY DEVELOP MONDAY AFTERNOON FROM GARDEN CITY AND LIBERAL WESTWARD. HOWEVER, SURFACE WINDS WILL BE MARGINAL. NO WATCH OR WARNING WAS ISSUED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... DDC 39 59 36 59 / 10 10 10 30 GCK 34 56 34 60 / 10 10 10 20 EHA 33 53 32 59 / 0 10 10 20 LBL 33 57 34 60 / 0 10 10 30 HYS 41 59 37 60 / 10 10 10 20 P28 46 61 41 60 / 10 20 20 40 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ EARLY THIS MORNING FOR KSZ030-031-043>046-061>066-074>081-084>090. && $$ UPDATE...RUSSELL SHORT TERM...FINCH LONG TERM....GERARD AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1130 PM CDT SUN MAR 18 2012 ...UPDATE FOR THUNDERSTORM TRENDS AND WINDS... .UPDATE... ISSUED AT 1123 PM CDT SUN MAR 18 2012 HAVE UPDATED POPS AND WEATHER THROUGH THE OVERNIGHT TO ACCOUNT FOR EXPECTED PRECIPITATION TREND. THE HRRR HAS A DECENT TREND ON POPS EVOLUTION. A NARROW LINE OF THUNDERSTORMS ARE RAPIDLY DEVELOPING ALONG THE COLD FRONT SPREADING ACROSS THE TEXAS PANHANDLE NORTHEASTWARD FROM AMARILLO. THE LINE SHOULD GROW UPSCALE INTO THE NOW WEAKENING INSTABILITY FIELD OVER CENTRAL KANSAS THROUGH THE OVERNIGHT. THE ARW AND NMM NAM/WRF RUNS ARE SUPPORTIVE OF SUCH AN EVOLUTION WITH SOME DIFFERENCES IN PLACEMENT. THE NAM SURFACE WIND FIELD INDICATES WINDS SHOULD VEER AND WEAKEN IN THE COMING HOURS AS THE SURFACE TROUGH OVER EASTERN COLORADO MOVES EAST. AT THIS TIME ONLY A COUPLE OF METAR OBSERVATIONS ARE CLOSE TO OR MEETING WIND ADVISORY CRITERIA. WE PLAN TO ALLOW THE CURRENT WIND ADVISORY TO EXPIRE AT MIDNIGHT. UPDATE ISSUED AT 640 PM CDT SUN MAR 18 2012 WILL GO AHEAD AND LET THE RED FLAG WARNING FOR MORTON AND STANTON COUNTY EXPIRE ON TIME AT 7 PM CDT. HUMIDITIES ARE RISING ABOVE 15 PERCENT. A FEW THUNDERSTORMS WERE FORMING ALONG THE DRYLINE AND MOVING NORTH NORTHEAST AT AROUND 45 MPH FROM GARDEN CITY TO SCOTT CITY. SOME STORM SPLITTING WAS OCCURRING BUT UPDRAFTS SO FAR HAVE NOT BEEN ABLE TO SUSTAIN THEMSELVES LONG ENOUGH FOR SEVERE THRESHOLDS. AS THE SUN SETS THE PROBABILITY FOR SEVERE THUNDERSTORMS WILL DECREASE. HOWEVER LATER TONIGHT AROUND OR AFTER MIDNIGHT AS THE UPPER TROUGH AND COLD POOL ALOFT MOVES INTO WESTERN KANSAS A MARGINALLY SEVERE MCS MAY FORM WITH HAIL LESS THAN OR UP TO DIME AND QUARTER SIZE. A LOW LEVEL JET OF 60 KTS WILL CONTINUE WITH STRONG SURFACE WINDS THROUGH AROUND MIDNIGHT. THERE MAY BE A BRIEF LULL IN THE STRONG WINDS AROUND SUNSET THEN THEY SHOULD PICK BACK UP AGAIN. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 325 PM CDT SUN MAR 18 2012 A DEEP UPPER-LEVEL TROUGH WAS MOVING TROUGH THE INTERMOUNTAIN WEST THIS AFTERNOON. AHEAD OF THIS FEATURE, STRONG LEE TROUGHING WAS OCCURRING ALONG THE HIGH PLAINS. A SURFACE DRYLINE WAS LOCATED ACROSS FAR WESTERN KANSAS. TO THE EAST OF THE DRYLINE, LOW LEVEL MOISTURE WAS IN PLACE AND CAPPING WAS BEING ERODED THROUGH STRONG DAYTIME HEATING. HOWEVER, A STRONG CAP WAS STILL IN PLACE WELL AHEAD OF THE DRYLINE AT DODGE CITY PER MODEL SOUNDINGS. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE DRYLINE BY 5 PM WITH INTENSE DAYTIME HEATING. GIVEN THE STRONG SHEAR AND CAPE AROUND 2000 J/KG, LARGE HAIL WILL ACCOMPANY THE STRONGEST STORMS. DURING THE EVENING HOURS AS THE LOWER LEVELS COOL, CLOUD HEIGHTS WILL DECREASE AS THE STORMS MOVE EAST OF THE DRYLINE. THEREFORE, A TORNADO OR TWO CAN`T BE RULED OUT DURING THE EVENING BEFORE THE LOWER LEVELS STABILIZE TOO MUCH AND SURFACE BASED STORMS DIMINISH. LATER TONIGHT, MID-LEVEL COOLING ASSOCIATED WITH THE UPPER-LEVEL SYSTEM WILL APPROACH, ALONG WITH A NORTH TO SOUTH ORIENTED COLD FRONT. SO ADDITIONAL THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT, ESPECIALLY OVER SOUTH CENTRAL KANSAS WHERE THE DEEPEST MOISTURE WILL RESIDE. THESE STORMS SHOULD NOT BE AS SEVERE SINCE THE LOWER TO MID-LEVEL WINDS WILL BE UNIDIRECTIONAL BY THAT TIME, ALONG WITH MUCH LOWER CAPE VALUES DUE TO THE LOSS OF DAYTIME HEATING. NEVERTHELESS, MARGINALLY SEVERE HAIL IS POSSIBLE. WARM OVERNIGHT LOWS IN THE LOWER 60S CAN BE EXPECTED AROUND MEDICINE LODGE AND PRATT WHERE 60F DEWPOINTS AND 15KT WINDS WILL BE LOCATED. COOLER TEMPERATURES IN THE 40S CAN BE EXPECTED IN FAR WESTERN KANSAS IN THE DRIER AIR. CLEARING CAN BE EXPECTED ON MONDAY AS THE COLD FRONT SWEEPS ACROSS SOUTHWEST KANSAS IN THE MORNING. DESPITE THE FRONTAL PASSAGE, TEMPERATURES WILL NOT BE ALL THAT COLD SINCE THIS IS NOT AN ARCTIC AIRMASS AND SINCE SURFACE WINDS WILL HAVE A DOWNSLOPE COMPONENT. THE COOLEST TEMPERATURES SHOULD BE ALONG THE COLORADO BORDER ON THE HIGHER TERRAIN, WITH WARMER TEMPERATURES IN CENTRAL KANSAS WHERE DOWNSLOPE WARMING WILL BE GREATER. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 305 AM CDT SUN MAR 18 2012 THE LATEST MODEL RUNS OF THE ECMWF, GFS AND GEM ALL SHOW THE LARGE SCALE UPPER LEVEL TROUGH EXTENDING FROM CENTRAL WYOMING SOUTH TO NORTHERN ARIZONA BY 12Z MONDAY. STRONG UPPER LEVEL DYNAMICS WILL BE FLOWING THROUGH CENTRAL KANSAS, AND A COLD FRONT WILL BE DIVIDING OUR CWA FROM WEST TO EAST. MOISTURE WILL BE HIGH IN OUR EXTREME EASTERN COUNTIES, AND THERE WILL CONTINUE TO BE A GOOD CHANCE FOR THUNDERSTORMS ACROSS OUR EASTERN 2 TIER OF COUNTIES. THE PRECIPITATION SHOULD MOVE EAST OF OUR AREA BY 00Z TUESDAY, SO MONDAY NIGHT AND TUESDAY WILL NOT HAVE POPS IN. BY TUESDAY NIGHT, AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CUT OFF AND BE CENTERED OVER NORTH CENTRAL OKLAHOMA. THIS COULD BRING SOME WRAP AROUND RAIN SHOWERS TO OUR SOUTHEAST ZONES BOTH TUESDAY NIGHT AND WEDNESDAY. THE MOISTURE WILL GET DEEPER BY THURSDAY, SO THE NEW CR_EXTD_INIT OR CONSALL MODELS SHOW THURSDAY WITH 20 PERCENT CHANCES FOR SHOWERS, AS FAR WEST AS STANTON AND SCOTT COUNTIES. WENT ON THE LOWER SIDE FOR QPF AMOUNTS THURSDAY, AS THE SHOWERS WILL PROBABLY BE WIDELY SCATTERED AND HIGH BASED/ELEVATED. THE LARGE CUT OFF UPPER LOW PRESSURE WILL ADVANCE EAST THURSDAY NIGHT, BRINGING AN END TO THE PRECIP CHANCES. A RATHER LARGE SCALE UPPER LEVEL HIGH PRESSURE RIDGE WILL BUILD IN INTO THE WESTERN PLAINS FROM FRIDAY INTO SATURDAY. THIS WILL MEAN A WARMING TREND SETTING IN. MONDAY HIGHS WILL RANGE FROM THE MID 50S IN OUR SOUTHWEST TO THE UPPER 60S IN OUR SOUTHEAST. TUESDAY MAY BE THE COLDEST DAY IN THE EXTENDED PERIOD, WITH HIGHS ONLY IN THE LOWER 50S IN OUR WEST AND THE LOWER 60S ACROSS OUR SOUTHEAST COUNTIES. SO TECHNICALLY, THE WARMING TREND WILL BEGIN WEDNESDAY WHEN MAX TEMPS RISE TO THE LOWER 60S. MAXIMUM TEMPERATURES SHOULD WARM TO THE MID 60S BY THURSDAY, THE UPPER 60S TO LOWER 70S BY FRIDAY, AND THEN WITH THE UPPER LEVEL HIGH PRESSURE RIDGE IN FULL FORCE BY THE WEEKEND, HIGHS SATURDAY WILL TOP OUT IN THE 70F TO 75F DEGREE RANGE. MINIMUM TEMPERATURES THROUGH THE EXTENDED PERIOD WILL GO THROUGH A WIDE RANGE. TUESDAY MORNING WILL SEE THE INITIAL SURGE OF COLD AIR SNEAK INTO OUR WESTERN 1/3RD OF THE CWA, WITH MINS IN THE LOWER TO MID 30S. EASTERN COUNTIES TUESDAY WILL SEE ELEVATED MINS IN THE LOWER TO MID 40S DUE TO THE MOIST SOIL CONDITIONS. WEDNESDAY MORNING WILL LIKELY BE THE COLDEST MORNING AS COLDER AIR SEEPS EASTWARD, WITH MIN TEMPERATURES IN THE UPPER 20S IN OUR FAR WEST AND RANGING TO NEAR 40F DEGREES IN THE MEDICINE LODGE AREA. BY THURSDAY MORNING, SOME WRAP AROUND MOISTURE WILL BE FILTERING IN, AND LOWS WILL RANGE FROM 37F DEGREES IN HAMILTON COUNTY TO 44F DEGREES IN BARBER COUNTY. FRIDAY AND SATURDAY WILL SEE MORNING LOW TEMPERATURES IN THE LOWER 40S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY) ISSUED AT 600 PM CDT SUN MAR 18 2012 STRONG SOUTHEAST WINDS WILL CONTINUE THIS EVENING WITH GUSTS TO 35 KTS. VFR CIGS WILL CONTINUE WITH A FEW THUNDERSTORMS, SOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. AN ISOLATED TORNADO CANNOT BE RULED OUT AS A LOW LEVEL JET STRENGTHENS TO 60 KTS BY THROUGH 03Z. HOWEVER THE BOUNDARY LAYER WILL BE COOLING WITH MORE CLOUDS MOVING IN. AFTER MIDNIGHT LOOK FOR GENERAL MCS WITH MARGINAL SEVERE HAIL POSSIBLE THROUGH ABOUT 12-15Z TONIGHT WITH UPPER LEVEL COOLING AS AN UPPER TROUGH MOVES INTO WESTERN KANSAS. && .FIRE WEATHER... ISSUED AT 640 PM CDT SUN MAR 18 2012 CRITICAL FIRE WEATHER CONDITIONS MAY DEVELOP MONDAY AFTERNOON FROM GARDEN CITY AND LIBERAL WESTWARD. HOWEVER, SURFACE WINDS WILL BE MARGINAL. NO WATCH OR WARNING WAS ISSUED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 66 39 59 / 80 20 10 10 GCK 46 63 34 56 / 30 10 10 10 EHA 44 59 33 53 / 40 0 0 10 LBL 47 63 33 57 / 70 0 0 10 HYS 57 71 41 59 / 70 40 10 10 P28 62 69 46 61 / 40 70 10 20 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ MONDAY FOR KSZ030- 031-043>046-061>066-074>081-084>090. && $$ UPDATE...RUSSELL SHORT TERM...FINCH LONG TERM....GERARD AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
158 AM EDT MON MAR 19 2012 .SYNOPSIS... A SLOW MOVING UPPER LEVEL TROUGH WILL BRING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT. SUNSHINE MAY HELP DEVELOP ISOLATED THUNDERSTORMS MONDAY AFTERNOON, AS WARM TEMPERATURES WILL CONTINUE THIS WEEK. && .NEAR TERM /THROUGH TODAY/... UPDATED TO REMOVE THUNDER FOR ALL BUT THE SOUTHERN COUNTIES WHERE THE RISK OF THUNDER REMAINS MAINLY SOUTH OF THE MASON DIXON LINE. RAIN SHOWERS IN THE NORTH WILL SLOWLY END FROM WEST TO EAST AS THE SHORT WAVE MOVES EAST OF THE DISTRICT TOWARD DAYBREAK. NOCTURNAL COOLING OF A RAIN- MOISTENED SURFACE LAYER CAN RESULT IN PATCHY FOG OVERNIGHT INTO MONDAY MORNING. CLOUDS WILL ERODE DURING MONDAY MORNING, TO PROVIDE SOME SUNSHINE BY AFTERNOON. THIS MAY GIVE RISE TO ENOUGH INSTABILITY FOR ISOLATED AFTERNOON THUNDERSTORMS. TWEAKED TEMPERATURES USING RECENT HRRR AND GFS LAMP MODEL OUTPUT. THESE SHOW LOWS TONIGHT SIMILAR TO SATURDAY NIGHT, AND HIGHS MONDAY A TAD WARMER THAN SUNDAY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... EXPECT SHOWER CHANCES TO DECREASE MONDAY NIGHT WITH NOCTURNAL COOLING OF THE SURFACE LAYER REDUCING INSTABILITY. WITH UPPER LEVEL SHORT-WAVE TROUGH HAVING PAST EAST OF THE MOUNTAINS TUESDAY, HAVE FORECASTED DRY CONDITIONS TUESDAY AND WEDNESDAY. BOTH MAV/MET GUIDANCE HAVE TEMPERATURES REACHING VERY CLOSE TO 80 BY MIDWEEK AND WITH STRONG RIDGE STATIONED TO THE EAST AND SOUTHERLY FLOW...FELT NO REASON TO STRAY FROM THESE NUMBERS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... REGION WILL BE UNDER AN UPPER LEVEL RIDGE INTO THURSDAY WITH MILD TEMPERATURES. THERE MAY BE ENOUGH LOW LEVEL MOISTURE THAT A DIURNAL SHOWER IS POSSIBLE THURSDAY...BUT OVERALL A DRY FORECAST. LARGE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL GRADUALLY COME EAST BY FRIDAY WITH SHOWERS INTO SATURDAY. MODELS HAVE TIMING DIFFERENCES BY THE DAY 7 TIME PERIOD WITH A SHOT OF COLDER AIR MOVING DOWN FROM THE NORTHERN PLAINS BEHIND THE SATURDAY SYSTEM. USED HPC GUIDANCE FOR CONSISTENCY. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... A MID-LEVEL DISTURBANCE WILL CROSS THE TERMINALS, BRINGING SHOWERS AND ISOLATED THUNDERSTORMS TO THE AREA THROUGH DAWN. AT THIS TIME, HAVE LEFT OUT MENTION OF CB AND -TSRA AS STORMS ARE FORECAST TO MISS KZZV/KHLG/KMGW. THUS, VFR CONDITIONS ARE FORECAST ACROSS THE TERMINALS UNTIL THE PRE-DAWN HOURS. CLEARING BEHIND THE MID- LEVEL WAVE MAY ALLOW FOR FOG TO DEVELOP NEAR DAWN. MVFR VISIBILITIES WITH FOG ARE FORECAST AT KPIT/KAGC/KBVI/KHLG WITH IFR POSSIBLE AT KZZV. VFR CONDITIONS WILL PREVAIL MUCH OF THE DAY TODAY WITH ISOLATED CONVECTION POSSIBLE IN THE LATE AFTERNOON. CONFIDENCE IS TOO LOW AT THIS TIME TO MENTION THIS IN TAFS. WINDS THROUGHOUT THE MAJORITY OF THE FORECAST PERIOD WILL BE SOUTHWESTERLY AROUND 5KTS. OUTLOOK...TUESDAY THROUGH FRIDAY... HIGH PRESSURE ALOFT WILL DOMINATE INTO THURSDAY WITH GENERAL VFR CONDITIONS. SHOWERS AND POSSIBLE RESTRICTIONS WILL RETURN FRIDAY AS A STORM SYSTEM MOVES EAST FROM THE CENTRAL PLAINS STATES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1250 AM EDT MON MAR 19 2012 .SYNOPSIS... A SLOW MOVING UPPER LEVEL TROUGH WILL BRING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT. SUNSHINE MAY HELP DEVELOP ISOLATED THUNDERSTORMS MONDAY AFTERNOON, AS WARM TEMPERATURES WILL CONTINUE THIS WEEK. && .NEAR TERM /THROUGH TODAY/... UPDATED TO REMOVE THUNDER FOR ALL BUT THE SOUTHERN COUNTIES WHERE THE RISK OF THUNDER REMAINS MAINLY SOUTH OF THE MASON DIXON LINE. RAIN SHOWERS IN THE NORTH WILL SLOWLY END FROM WEST TO EAST AS THE SHORT WAVE MOVES EAST OF THE DISTRICT TOWARD DAYBREAK. NOCTURNAL COOLING OF A RAIN- MOISTENED SURFACE LAYER CAN RESULT IN PATCHY FOG OVERNIGHT INTO MONDAY MORNING. CLOUDS WILL ERODE DURING MONDAY MORNING, TO PROVIDE SOME SUNSHINE BY AFTERNOON. THIS MAY GIVE RISE TO ENOUGH INSTABILITY FOR ISOLATED AFTERNOON THUNDERSTORMS. TWEAKED TEMPERATURES USING RECENT HRRR AND GFS LAMP MODEL OUTPUT. THESE SHOW LOWS TONIGHT SIMILAR TO SATURDAY NIGHT, AND HIGHS MONDAY A TAD WARMER THAN SUNDAY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... EXPECT SHOWER CHANCES TO DECREASE MONDAY NIGHT WITH NOCTURNAL COOLING OF THE SURFACE LAYER REDUCING INSTABILITY. WITH UPPER LEVEL SHORT-WAVE TROUGH HAVING PAST EAST OF THE MOUNTAINS TUESDAY, HAVE FORECASTED DRY CONDITIONS TUESDAY AND WEDNESDAY. BOTH MAV/MET GUIDANCE HAVE TEMPERATURES REACHING VERY CLOSE TO 80 BY MIDWEEK AND WITH STRONG RIDGE STATIONED TO THE EAST AND SOUTHERLY FLOW...FELT NO REASON TO STRAY FROM THESE NUMBERS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... REGION WILL BE UNDER AN UPPER LEVEL RIDGE INTO THURSDAY WITH MILD TEMPERATURES. THERE MAY BE ENOUGH LOW LEVEL MOISTURE THAT A DIURNAL SHOWER IS POSSIBLE THURSDAY...BUT OVERALL A DRY FORECAST. LARGE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL GRADUALLY COME EAST BY FRIDAY WITH SHOWERS INTO SATURDAY. MODELS HAVE TIMING DIFFERENCES BY THE DAY 7 TIME PERIOD WITH A SHOT OF COLDER AIR MOVING DOWN FROM THE NORTHERN PLAINS BEHIND THE SATURDAY SYSTEM. USED HPC GUIDANCE FOR CONSISTENCY. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... MAIN FORECAST CONCERN WILL BE EASTWARD PASSAGE OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT, THAT CAN RESULT IN MAINLY MVFR CONDITIONS. SUBSEQUENT NIGHTTIME COOLING OF A RAIN-MOISTENED SURFACE LAYER MAY RESULT IN PATCHES OF IFR FOG THROUGH 14Z. AFTER FOG DISSIPATES MONDAY MORNING, EXPECT VFR CONDITIONS FOR THE REMAINDER OF THE DAY. ISOLATED THUNDERSTORMS MAY DEVELOP DURING THE AFTERNOON BUT HAVE LOW CONFIDENCE ANY TAF SITES WILL BE AFFECTED. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... HIGH PRESSURE WILL DOMINATE INTO THURSDAY WITH GENERAL VFR CONDITIONS. SHOWERS AND POSSIBLE RESTRICTIONS WILL RETURN FRIDAY AS A STORM SYSTEM MOVES EAST FROM THE CENTRAL PLAINS STATES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1240 AM EDT MON MAR 19 2012 .SYNOPSIS... A SLOW MOVING UPPER LEVEL TROUGH WILL BRING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT. SUNSHINE MAY HELP DEVELOP ISOLATED THUNDERSTORMS MONDAY AFTERNOON, AS WARM TEMPERATURES WILL CONTINUE THIS WEEK. && .NEAR TERM /THROUGH TODAY/... UPDATED TO REMOVE THUNDER FOR ALL BUT THE SOUTHERN MOST COUNTIES WHERE THE RISK OF THUNDER REMAINS MAINLY SOUTH OF THE MASON DIXON LINE. RAIN SHOWERS IN THE NORTH WILL SLOWLY END FROM WEST TO EAST AS THE SHORT WAVE MOVES EAST OF THE DISTRICT TOWARD DAYBREAK. NOCTURNAL COOLING OF A RAIN- MOISTENED SURFACE LAYER CAN RESULT IN PATCHY FOG OVERNIGHT INTO MONDAY MORNING. CLOUDS WILL ERODE DURING MONDAY MORNING, TO PROVIDE SOME SUNSHINE BY AFTERNOON. THIS MAY GIVE RISE TO ENOUGH INSTABILITY FOR ISOLATED AFTERNOON THUNDERSTORMS. TWEAKED TEMPERATURES USING RECENT HRRR AND GFS LAMP MODEL OUTPUT. THESE SHOW LOWS TONIGHT SIMILAR TO SATURDAY NIGHT, AND HIGHS MONDAY A TAD WARMER THAN SUNDAY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... EXPECT SHOWER CHANCES TO DECREASE MONDAY NIGHT WITH NOCTURNAL COOLING OF THE SURFACE LAYER REDUCING INSTABILITY. WITH UPPER LEVEL SHORT-WAVE TROUGH HAVING PAST EAST OF THE MOUNTAINS TUESDAY, HAVE FORECASTED DRY CONDITIONS TUESDAY AND WEDNESDAY. BOTH MAV/MET GUIDANCE HAVE TEMPERATURES REACHING VERY CLOSE TO 80 BY MIDWEEK AND WITH STRONG RIDGE STATIONED TO THE EAST AND SOUTHERLY FLOW...FELT NO REASON TO STRAY FROM THESE NUMBERS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... REGION WILL BE UNDER AN UPPER LEVEL RIDGE INTO THURSDAY WITH MILD TEMPERATURES. THERE MAY BE ENOUGH LOW LEVEL MOISTURE THAT A DIURNAL SHOWER IS POSSIBLE THURSDAY...BUT OVERALL A DRY FORECAST. LARGE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL GRADUALLY COME EAST BY FRIDAY WITH SHOWERS INTO SATURDAY. MODELS HAVE TIMING DIFFERENCES BY THE DAY 7 TIME PERIOD WITH A SHOT OF COLDER AIR MOVING DOWN FROM THE NORTHERN PLAINS BEHIND THE SATURDAY SYSTEM. USED HPC GUIDANCE FOR CONSISTENCY. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... MAIN FORECAST CONCERN WILL BE EASTWARD PASSAGE OF SHOWERS AND SCATTERED THUNDERSTORMS OVERNIGHT, THAT CAN RESULT IN MAINLY MVFR CONDITIONS. SUBSEQUENT NIGHTTIME COOLING OF A RAIN-MOISTENED SURFACE LAYER MAY RESULT IN PATCHES OF IFR FOG THROUGH 14Z. AFTER FOG DISSIPATES MONDAY MORNING, EXPECT VFR CONDITIONS FOR THE REMAINDER OF THE DAY. ISOLATED THUNDERSTORMS MAY DEVELOP DURING THE AFTERNOON BUT HAVE LOW CONFIDENCE ANY TAF SITES WILL BE AFFECTED. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... HIGH PRESSURE WILL DOMINATE INTO THURSDAY WITH GENERAL VFR CONDITIONS. SHOWERS AND POSSIBLE RESTRICTIONS WILL RETURN FRIDAY AS A STORM SYSTEM MOVES EAST FROM THE CENTRAL PLAINS STATES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS GLASGOW MT
359 AM MDT MON MAR 19 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY... STRONG LATE WINTER STORM IS UNDERWAY ACROSS CENTRAL AND EASTERN MONTANA. NATIONAL ATTENTION GIVEN BY SPC MESOSCALE DISCUSSION AND SATELLITE PRECIPITATION ESTIMATES. SHORT TERM MODEL QPF DEPICTIONS HAVE CONVERGED ON A VERY WET AND HEAVY PRECIPITATION EVENT FOR TODAY. SIGNIFICANT GRADIENT OF MANY WEATHER ELEMENTS WILL OCCUR ACROSS THE CWA TODAY. NEAR NOTHING IN OUR EASTERN ZONES...TO A FULL OUT BLIZZARD IN OUR WESTERN ZONES. TIGHT SURFACE LOW PRESSURE OVER SOUTHEASTERN MONTANA WILL PUSH NORTH AND EAST...ALLOWING STRONG WINDS TO WRAP AROUND THE WESTERN SIDE OF THE LOW. WINDS HAVE ALREADY INCREASED EARLY THIS MORNING MORE THAN ANTICIPATED. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE LIKELY TODAY. MODERATE TO HEAVY SNOW ALONG WITH NORTHWESTERLY WINDS OF 30 TO 40 MPH WILL EASILY RESULT IN BLIZZARD CONDITIONS FOR SOUTHWEST PHILLIPS COUNTY AND PETROLEUM COUNTY. FELT IT WAS BEST TO UPGRADE TO A BLIZZARD WARNING FOR THOSE ZONES AND GIVE BUFFER ZONES OF WINTER STORM WARNING AND WINTER WEATHER ADVISORY FURTHER EAST THROUGH OUR CENTRAL CWA. RECENT HRRR MODEL RUNS HAVE BEEN SLIDING THE PRECIPITATION PROGRESSIVELY FURTHER EAST THAN PREVIOUS MODEL RUNS. GREATEST PRECIPITATION IMPACT WILL BE WITH HEAVY SNOW BETWEEN 12Z AND 18Z. GREATEST WIND IMPACT WILL BE NORTHWESTERLY WINDS IN THE 30G40KT RANGE THROUGHOUT THE DAY. STORM WILL DIMINISH QUICKLY TONIGHT AND DISAPPEAR ENTIRELY AFTER MIDNIGHT AS THE LOW PRESSURE SYSTEM EXITS NORTHEASTWARD INTO CANADA...TAKING THE MAIN FORCING AND MOISTURE WITH IT. TUESDAY THROUGH WEDNESDAY...UPPER LEVEL FLOW BECOMES MORE ZONAL WITH A SLIGHT SOUTHWESTERLY COMPONENT TO IT. ENOUGH OF A HIGH PRESSURE INFLUENCE FROM THE SOUTH WILL KEEP PRECIPITATION AWAY AS TEMPERATURES BEGIN TO SLOWLY REBOUND TO ABOVE NORMAL LEVELS AGAIN INTO MID WEEK. BMICKELSON .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SOUTHWEST FLOW ALOFT WILL PREVAIL FOR THURSDAY AND FRIDAY WITH AN UPPER TROUGH TO THE WEST AND RIDGE TO THE EAST. NORTHEAST MONTANA WILL BE WARM AND DRY BEING CLOSER TO THE RIDGE THAN THE TROUGH. A SLOW MOVING COLD FRONT DROP SOUTH ACROSS THE FORECAST AREA SATURDAY AND SUNDAY. MODELS BEGIN TO DIFFER IN THEIR SOLUTIONS AT THIS POINT BUT THEY POINT TOWARDS SOME MOISTURE WITH THIS FRONT AND POSSIBLY A SHORTWAVE OR TWO IN THE SOUTHWEST FLOW ALOFT. WILL MENTION A SLIGHT CHANCE OF SHOWERS. GFS IS FASTER THAN THE ECMWF WITH BRINGING THE UPPER TROUGH INLAND EARLY NEXT WEEK. WILL MENTION A SLIGHT CHANCE OF RAIN OR SNOW SHOWERS ON MONDAY DEPENDING ON TEMPERATURES. FORRESTER && .AVIATION... KGGW BEING IN OR NEAR THE MAIN BAND OF RAIN/SNOW THIS MORNING WILL SEE A MIX OF IFR/MVFR CONDITIONS THIS MORNING WITH STRONG NORTH WINDS. KOLF WILL SEE A VARIATION OF IFR/MVFR AND VFR CONDITIONS THIS MORNING WITH THE DEEP LOW PRESSURE SYSTEM EXPECT TO PASS NEAR KGGW AND KOLF THIS MORNING...A LULL IN THE WINDS IS EXPECTED IN THE LATE MORNING BEFORE STRONG WEST WINDS 20-30 KNOTS DEVELOP ON THE BACK SIDE OF THE LOW THIS AFTERNOON. KGGW AND KOLF WILL SEE A MIX OF IFR AND MVFR CONDITIONS THIS AFTERNOON WITH RAIN CHANGING TO SNOW BEFORE THE PRECIP ENDS AROUND 00Z AND CONDITIONS IMPROVE TO VFR BY 02Z. KSDY AND KGDV WILL BY ON THE DRY EAST SIDE OF THE LOW THIS MORNING WITH VFR CONDITIONS. LIGHT AND VARIABLE WINDS EARLY WILL BECOME SOUTH 15 TO 20 KNOTS THIS MORNING AND GRADUALLY TURN SOUTHWEST THIS AFTERNOON AND WEST 20-30 KNOTS BY EVENING AS THE SURFACE LOW LIFTS NORTH. KSDY AND KGDV WILL REMAIN VFR FOR THE MOST PART THIS AFTERNOON BUT SOME LOW CLOUDS IN THE WRAP AROUND MOISTURE MAY GIVE THEM BRIEF PERIODS OF MVFR CONDITIONS. FORRESTER && .GLASGOW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR CENTRAL AND SOUTHERN VALLEY...NORTHERN VALLEY. BLIZZARD WARNING UNTIL MIDNIGHT MDT TONIGHT FOR PETROLEUM... SOUTHWEST PHILLIPS. WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR CENTRAL AND SOUTHEAST PHILLIPS...GARFIELD...NORTHERN PHILLIPS. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
323 AM CDT MON MAR 19 2012 .DISCUSSION... TIMING OF PERIODS OF SHOWERS AND THUNDERSTORMS WILL BE THE MAIN FORECAST CONCERN IN THE SHORT TERM AS UPPER WAVE CUTS OFF OVER SOUTHERN TEXAS AND LINGERS THERE THROUGH THE PERIOD. A SURFACE TROUGH WAS LOCATED ACROSS WESTERN NEBRASKA AT 07Z SEPARATING DRY AIR TO THE WEST FROM MOIST AIR TO THE EAST. ISOLATED SEVERE STORMS HAD DEVELOPED JUST EAST OF THE TROUGH EARLIER IN THE EVENING. MAIN AREA OF CONVECTION EARLY THIS MORNING WAS OVER THE TEXAS PANHANDLE INTO SOUTHWEST KANSAS. SHORT RANGE HRRR GRADUALLY LIFTS THE STORMS NORTHEAST THROUGH THE MORNING WITH CURRENT TIMING BRINGING INITIAL ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS INTO EASTERN NEBRASKA AROUND 15Z. WEAK MID LEVEL INSTABILITY INDICATED BY FORECAST SOUNDINGS THROUGH THE MORNING WITH BETTER FORCING AND DEEPER MOISTURE IN THE AFTERNOON FROM SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA. EASTERN PORTION OF THE CWA IS INCLUDED IN SLIGHT RISK FOR SEVERE TODAY WITH STRONG SHEAR BUT LIMITED CAPE INDICATED BY CURRENT FORECAST SOUNDINGS. THIS INITIAL WAVE THEN SHIFTS EAST INTO THE MISSISSIPPI VALLEY TONIGHT WITH POPS DECREASING ACROSS THE AREA. A SECONDARY SURFACE WAVE LIFTS NORTH FROM THE SOUTHERN PLAINS ON TUESDAY BRINGING ANOTHER CHANCE OF THUNDERSTORMS TO THE AREA... ESPECIALLY TUESDAY AFTERNOON AND TUESDAY EVENING. SURFACE FRONT ASSOCIATED WITH THIS WAVE BECOMES QUASI-STATIONARY OVER WESTERN IOWA DURING THIS TIME WITH SOME POTENTIAL FOR LOCALLY HEAVY RAIN FROM EXTREME SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA...ALTHOUGH CURRENT FORECAST TRENDS PLACE AXIS OF HEAVY RAIN JUST EAST OF THE AREA. POPS AGAIN DECREASE TUESDAY NIGHT OVER THE AREA AS SURFACE WAVE LIFTS NORTHEAST AND WEAKENS. CLOSED UPPER LOW OVER TEXAS BEGINS TO IMPACT THE AREA ON WEDNESDAY AND WEDNESDAY NIGHT AS THE SYSTEM LIFTS NORTH BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS INTO THE AREA. TEMPERATURES EXPECTED TO STAY ON THE MILD SIDE ALTHOUGH THE CLOUD COVER AND PRECIP WILL KEEP READINGS COOLER THAN SEEN THE PAST FEW DAYS. && .AVIATION... 06Z TAFS FOR KOFK...KLNK AND KOMA. DEVELOPING MVFR CIGS NEAR FL025 WILL SPREAD ACROSS ALL EASTERN NEBRASKA TAF SITES SHORTLY AFTER 06Z. STRONG SOUTH WINDS GUSTING NEAR 30KTS WILL ALSO CONTINUE OVERNIGHT AND MUCH OF MONDAY. RAIN AND CIGS NEAR FL015 ARE EXPECTED TO DEVELOP AROUND 12Z AND PERSIST MUCH OF THE MORNING. A FEW THUNDERSTORMS ARE POSSIBLE NEAR KLNK AND KOMA...MAINLY DURING THE 16Z TO 22Z TIME FRAME MONDAY...WITH THESE STORMS SHIFTING EAST OF THE AREA BY 00Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ FOBERT/DERGAN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
112 AM CDT MON MAR 19 2012 .AVIATION... CLEARING SKIES OVER WESTERN NEBRASKA THROUGH THE EARLY MORNING HOURS THEN MID AND HIGH CLOUDS BUILD BACK IN BY SUNRISE. SOME LOWER STRATUS AT BKN025 TO THE EAST OF HIGHWAY 83 WILL CONTINUE INTO THE MORNING. STRONG SOUTHEAST FLOW WILL CONTINUE OVER WESTERN NEBRASKA THROUGH THE EARLY MORNING HOURS AND THEN GRADUALLY SHIFT TO THE SOUTHWEST THROUGH THE DAY MONDAY. && .PREV DISCUSSION... /ISSUED 742 PM CDT SUN MAR 18 2012/ UPDATE... DISCUSSION... WIND ADVISORY CONDITIONS SHOULD CONTINUE NEARLY UNABATED THIS EVENING AS THE LOW LEVEL JET INCREASES...A PACIFIC COLD FRONT PUSHES INTO THE PANHANDLE AND 985 MB LOW PRESSURE ACROSS WY LIFTS NORTH INTO WRN SD/ERN MT AND DEEPENS TO NEAR 980 MB TONIGHT. A HIGH WIND WARNING CONTINUES ACROSS WRN NEB AS THIS AREA IS MOST PRONE TO HIGH WIND GUSTS AND THE RUC SUGGESTED A 65KT 850 MB JET. THE RED FLAG WARNING HAS BEEN EXTENDED UNTIL 06Z AS EARLIER SOLNS OF THE RUC INDICATED VERY LOW RH...LESS THAN 25 PERCENT UNTIL 06Z BUT THE MODEL HAS SINCE BACKED OFF AS THE DRYLINE CONTINUES TO RETREAT WEST THROUGH KOGA. PREV DISCUSSION... /ISSUED 621 PM CDT SUN MAR 18 2012/ UPDATE... AVIATION... VFR IS EXPECTED WEST OF HIGHWAY 83 TONIGHT AND MONDAY. A POWERFUL PACIFIC COLD FRONT WILL MOVE EAST THROUGH THE FCST OVERNIGHT. ISOLATED STRONG OR SEVERE THUNDERSTORMS ARE POSSIBLE...MAINLY ALONG AND EAST OF HIGHWAY 83. MVFR CIGS MAY DEVELOP ALONG AND EAST OF HIGHWAY 83 TONIGHT THROUGH 15Z AHEAD OF THE COLD FRONT. VFR IS EXPECTED AFTER 15Z ALL AREAS. WINDS AT 18030G45KT WILL SUBSIDE TO BY ROUGHLY 06Z. PREV DISCUSSION... /ISSUED 325 PM CDT SUN MAR 18 2012/ SYNOPSIS... H5 HAND ANALYSIS THIS MORNING INDICATING A TROUGH OF LOW PRESSURE EXTENDING ALONG THE PACIFIC COAST FROM WASHINGTON TO SRN CALIFORNIA. HT FALLS WERE GREATEST OVER FAR SRN CA AND ARIZONA WITH 120 METER FALLS AT FLAGSTAFF AND 110 METER FALLS AT TUSCON. WINDS HAVE FINALLY BEGUN TO PICK UP ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON WITH OGALLALA GUSTING TO 45 MPH LAST HOUR AND IMPERIAL 43 MPH. RECORD HIGHS HAVE ALREADY BEEN SET AT IMPERIAL AND VALENTINE THIS AFTERNOON. AS OF 3 PM CDT...NORTH PLATTE TIED ITS RECORD OF 84 DEGREES. RED FLAG CONDS WERE BEING MET ACROSS ALL FIRE WEATHER FORECAST ZONES BUT 209 THIS AFTERNOON...AND WITH THE STRENGTH OF THE WINDS...GLAD WE HAVE A RED FLAG WARNING IN PLACE EVERYWHERE. DISCUSSION... NEAR TERM...TONIGHT THROUGH WEDNESDAY...FORECAST CHALLENGES THROUGH WEDNESDAY...DEAL WITH WIND AND CONVECTION TONIGHT...FIRE WEATHER CONCERNS TOMORROW...A COLD FROPA TOMORROW NIGHT...THEN THE THREAT FOR PRECIPITATION INTO WEDS AS A CLOSED UPPER LEVEL LOW MEANDERS ACROSS THE SRN PLAINS. FOR TONIGHT...WINDS AND THUNDERSTORM CHANCES WILL BE THE MAIN FORECASTING CONCERNS. WITH RESPECT TO WINDS...SURFACE LOW PRESSURE WILL DEEPEN ACROSS NERN WYOMING LATER THIS AFTERNOON AND THIS EVENING...THEN LIFT NORTH INTO SERN MT AND WRN ND OVERNIGHT. THE LOW LEVEL PRESSURE GRADIENT WILL STEEPEN EAST OF THE PANHANDLE LATE THIS AFTERNOON AND THIS EVENING...BEFORE RELAXING TOWARD MORNING...AS A SURFACE TROUGH TRANSITIONS EAST. H85 WINDS INCREASE TO 40 TO 60 KTS EAST OF THE PANHANDLE LATER THIS EVENING...PEAKING AROUND 06Z. IF WE COULD MIX THE BULK OF THIS OUT...THE HIGH WIND WARNING UNTIL 01Z MAY NEED TO BE EXTENDED THIS EVENING. H925 AND H85 WINDS ARE UNIDIRECTIONAL THROUGH ABOUT 03Z...THEN DIVERGE TOWARD LATE EVENING. THIS WOULD LESSEN MIXING AND LEAD TO SLIGHTLY LOWER BOUNDARY LAYER WINDS. FOR NOW...WILL LET THE HIGH WIND WARNING RIDE TILL 8 PM CDT AND LET THE EVENING CREW DECIDE ON WEATHER OR NOT TO EXTEND THE WARNING OR ISSUE A WIND ADVZY. POPS THIS EVENING WERE TRIMMED OUT OF THE WESTERN ZONES AND WILL BE CONFINED TO THE CENTRAL AND SERN ZONES THIS EVENING. THE CHANGE WAS MADE TO ACCOMMODATE THE DRY LINE POSITION WHICH IS ALREADY EAST OF HIGHWAY 83 AS OF 2 PM CDT. SLIGHT CHANCE POPS WERE RETAINED IN THESE AREAS IF CONVECTION DECIDES TO FIRE ALONG THE DRYLINE LATE THIS AFTERNOON. BETTER CHANCES FOR PRECIPITATION IN EASTERN AREAS WILL ARRIVE OVERNIGHT AS TSRAS FROM WRN KS LIFT NEWD INTO THE CENTRAL AND EASTERN ZONES. INITIATION FORCING IS MUCH MORE FAVORABLE IN WRN KS AND THE TX AND OK PANHANDLES THIS EVENING AND ANY STORMS IN THE ERN ZONES WILL HAVE TO ORIGINATE IN THESE AREAS. WITH TIMING BEING IN THE OVERNIGHT...SEVERE THREAT IS EXPECTED TO BE MINIMAL...THOUGH GUSTY WINDS MAY BE POSSIBLE INVOF OF ANY THUNDERSTORMS...THANKS TO DECENT H85 WINDS. FIRE WEATHER CONCERNS AND PRECIPITATION CHANCES IN THE EAST HIGHLIGHT THE MONDAY FORECAST. BY MONDAY AFTERNOON...THE DRYLINE WILL PUSH EAST OF HIGHWAY 83...WITH VERY LOW DEW POINTS NOTED WEST OF THIS FEATURE IN THE WRN SANDHILLS AND ERN PANHANDLE. EVEN WITH COOLER HIGHS IE. 60S...FCST DEW POINTS IN THE HIGH SINGLE DIGITS AND LOWER TEENS WILL LEAD TO MIN RH`S AROUND 15 PERCENT MONDAY AFTERNOON WHICH IS NEAR CRITICAL CRITERIA. WINDS WILL BE THE WILD CARD IN ALL OF THIS AS LIGHTER WINDS ARE EXPECTED WEST OF THE DRYLINE TOMORROW. GUIDANCE FOR OGA HAS AFTERNOON WINDS RANGING FROM 10 TO 20 KTS WHICH WOULD BE BLO RED FLAG CRITERIA. WINDS ARE A TAD HIGHER IN THE PANHANDLE AND ACTUALLY APPROACH 25 MPH BRIEFLY BY MID AFTERNOON. ATTM THE GREATEST THREAT FOR RFW CONDS IS IN THE EASTERN PANHANDLE...BUT NOT ENOUGH CONFIDENCE YET TO PUSH OUT A FIRE WEATHER WATCH. BY MONDAY NIGHT...A COLD FRONT WILL TRACK ACROSS THE FORECAST AREA...JOINING THE DRYLINE ACROSS EASTERN PORTIONS OF NEBRASKA. DECIDED TO HOLD ONTO SOME POPS IN EASTERN AREAS MONDAY EVENING EAST OF THE APPG FRONT AND INVOF OF THE DRY LINE...WITH DRY CONDS EXPECTED FURTHER WEST. H85 TEMPS WILL STRUGGLE TO GET OUT OF THE SINGLE DIGITS TUESDAY...WHICH WILL LEAD TO HIGHS IN THE 50S...AND WILL BE THE COOLEST DAY OF THE PERIOD. IRONICALLY...TUESDAY...WILL HAVE HIGH TEMPS AROUND OR SLIGHTLY ABOVE NORMAL. DRY CONDS WILL CARRY OVER INTO WEDNESDAY AS THE CENTRAL PLAINS ARE CAUGHT BETWEEN EXITING LOW PRESSURE TO THE NORTH AND A DEVELOPING CLOSED LOW OFF TO THE SOUTH. THE SECOND FEATURE WILL MEANDER...THEN DRIFT NORTH TOWARD THE END OF THE WEEK...POSING A PLETHORA OF FORECASTING ISSUES TO THE AREA WEDNESDAY NIGHT AND THURSDAY AS THIS SYSTEM DRIFTS NORTH INTO KANSAS AND SRN NEBRASKA. CONFIDENCE IN THE TRACK AND TIMING OF THIS FEATURE STILL IN DOUBT AS THE FORECAST MODELS HAVE ONLY RECENTLY HINTED AT THE DEVELOPMENT OF A DOWN STREAM BLOCKING RIDGE AND A NWD MOVING CLOSED LOW. LONG TERM...THURSDAY THROUGH SUNDAY...AS MENTIONED EARLIER...THE MODELS ARE TRENDING TOWARD A CUTOFF LOW CREEPING NORTH INTO KANSAS...THEN EAST INTO THE LOWER MISSOURI VALLEY LATE IN THE WEEK AND INTO THE WEEKEND. ON THIS TRACK...POPS WILL NEED TO BE INCREASED IN SOME CENTRAL...SRN AND EASTERN AREAS TO ACCOMMODATE PRECIPITATION DEVELOPMENT ON THE NORTHWESTERN PERIPHERY OF THE LOW. WENT AHEAD AND INTRODUCED POPS IN THE SOUTHEAST AND EASTERN ZONES FOR WEDS NIGHT THROUGH THURSDAY. BEYOND FRIDAY...DRY CONDS ARE EXPECTED AS RIDGING ALOFT BUILDS BACK INTO THE CENTRAL CONUS. TEMPS ARE EXPECTED TO BE BACK IN THE 70S BY THE WEEKEND. FIRE WEATHER... FIRE CONCERNS WILL CONTINUE INTO THIS EVENING. WINDS ALOFT WILL BE ON THE INCREASE THROUGH THE REMAINDER OF THE AFTERNOON. AND WITH DEEP MIXING CONTINUING THROUGH EARLY EVENING...WILL CONTINUE TO GET THE STRONG WINDS BLOWING ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. WILL NOT BEGIN TO SEE RELATIVE HUMIDITY BEGIN TO RECOVER ABOVE CRITICAL LEVELS UNTIL AFTER SUNDOWN...SO RED FLAG WARNING WILL CONTINUE UNTIL THIS EVENING AS CONDITIONS REMAIN CRITICAL TO EXTREME FOR DANGEROUS FIRE BEHAVIOR. THE DRY AIR WILL STAY IN PLACE FOR MONDAY...ALTHOUGH TEMPERATURES WILL BE ABOUT 15 TO 20 DEGREES COOLER THAN TODAY. RELATIVE HUMIDITY WILL FALL TO AROUND 15 PERCENT IN LOCATIONS WEST OF HIGHWAY 83...HOWEVER WINDS IN THESE AREAS ARE EXPECTED TO BE LESS THAN 20KTS THROUGHOUT THE DAY. IN LOCATIONS TO THE EAST INTO CENTRAL NEBRASKA...WINDS WILL BE A BIT STRONGER /STILL 25KTS OR LOWER/ IN THE AFTERNOON...HOWEVER RELATIVE HUMIDITY WILL BE HIGHER AS WELL...25 TO 30 PERCENT. THEREFORE FIRE DANGER ON MONDAY IS NOT EXPECTED TO BE CRITICAL. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 4 AM CDT /3 AM MDT/ EARLY THIS MORNING FOR NEZ004>010-022>029-035>038-056>059-069>071-094. && $$ SHORT TERM/EXTENDED...TAYLOR AVIATION...POWER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
254 AM EDT MON MAR 19 2012 .SYNOPSIS... A SOUTHERLY FLOW OF UNSEASONABLY WARM AIR WILL CONTINUE FOR THE NEXT SEVERAL DAYS. AN UPPER LEVEL DISTURBANCE WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TODAY INTO TONIGHT. OTHERWISE...THOUGH...RAIN FREE CONDITIONS ARE EXPECTED THROUGH MIDWEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1230 AM UPDATE...LOCAL RADAR SHOWS ISOLATED LIGHT SHOWERS REDEVELOPING FROM THE CENTRAL SOUTHERN TIER ACROSS THE FINGER LAKES TO THE WESTERN MOHAWK VALLEY. HRRR AND LOCAL WRF INDICATE THIS ACTIVITY WILL PERSIST THROUGH THE OVERNIGHT PERIOD, ALTHOUGH ISOLATED, IN AN AREA OF HIGHER SFC DEW POINTS LOW/MID 50S. ADJUSTED POPS TO REFLECT ISOLATED ACTIVITY OVERNIGHT FROM ABOVE MENTIONED AREA WITH SLIGHT PROGRESSION EAST. NO OTHER CHANGES. 10 PM UPDATE...AN AREA OF BROKEN TO ISOLATED SHOWERS ON A LINE FROM SOUTHERN STEUBEN COUNTY NORTHEAST THROUGH THE FINGER LAKES CONTINUES TO FALL APART. EXPECT THIS TREND TO CONTINUE THROUGH MIDNIGHT. ASIDE FROM THIS PRECIPITATION...A QUICK LOOK AT THE REGIONAL RADAR SHOWS THAT WE SHOULD BE IN FOR A MAINLY DRY NIGHT ONCE WE GET RID OF THE SHOWERS CURRENTLY IN PLACE. THE NEXT AREA OF SHOWERS ACROSS OHIO IS IN DIRECT ASSOCIATION WITH A H5 SHORT WAVE ACROSS EASTERN OH. THIS SHORT WAVE IS ESSENTIALLY IN THE MIDDLE OF TWO H5 RIDGES (ONE TO OUR EAST OVER NEW ENGLAND AND ANOTHER ACROSS THE WESTERN OHIO VALLEY). DUE TO THIS...THE UPPER LEVEL FLOW IS VERY WEAK AND WE DO NOT EXPECT ANY LIFTING MECHANISM TO MOVE OUR WAY FOR THE REST OF THE OVERNIGHT. ON MONDAY AS THIS SHORT WAVE MOVES A BIT CLOSER AND WE GET SOME DAYTIME HEATING...SHOWER AND THUNDERSTORM CHANCES WILL BODILY INCREASE FROM MID-MORNING ON. 7 PM UPDATE...INCREASED CHANCE POPS TO LIKELY FROM THE FINGER LAKES INTO THE WESTERN MOHAWK VALLEY FOR THE NEXT FEW HOURS. AFTER WE LOSE OUR DAYTIME HEATING THE COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH AND WHILE A FEW RUMBLES OF THUNDER ARE STILL POSSIBLE...THIS THREAT SHOULD ALSO GO DOWN. EXPECT THAT THE AREA OF PRECIP NOW WILL NOT SHIFT TOO MUCH FARTHER SOUTH AND EAST SO THROUGH EARLY TONIGHT THE AREAS SEEING RAIN NOW WILL REMAIN THE MOST AT RISK. 3 PM UPDATE... SCTD SHRA/TSRA ARE POPPING UP LATE THIS AFTN ACRS WRN PA/NY...AS AN UPR-LVL WAVE APPROACHES...AND ACTS ON EXISTING INSTAB (ML CAPES IN THE 500-750 RANGE). WE EXPECT THIS ACTIVITY TO DRIFT VERY SLOWLY EWD...AND INTO OUR WRN/NRN ZNS IN THE 21-00Z TIME FRAME. ALTHOUGH THE AMS WILL CERTAINLY STABILIZE DIURNALLY AFTER SUNSET...THE HISTORY OF THIS SHRT WV HAS FEATURED EMBEDDED TSRA...EVEN IN THE OVERNIGHT PDS. THUS...WE`LL CONTINUE TO ADVERTISE SCTD SHRA AND ISOLD TSRA...MAINLY FROM THE FINGER LKS/CNTRL SRN TIER AREAS...UP ACROSS KSYR METRO...AND INTO THE MOHAWK VLY/SRN TUG HILL RGNS. AREAS TO THE S AND E OF KBGM SHOULD STAY MOSTLY RAIN-FREE OVERNIGHT. GIVEN AN INCREASE IN CLDS FROM THE W TNT (LESS RADIATIONAL COOLING)...AND A LOW-LVL TRAJECTORY MORE FROM THE S AND SW...AS OPPOSED TO THE SE...WE FEEL THE EXTENT OF MARINE LYR ST/FOG WILL BE MUCH LESS...AS COMPARED TO RECENT NGTS. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... 310 PM UPDATE... MODEL AGREEMENT REMAINS GOOD...ON THE SYNOPTIC SCALE...THAT THE ABV MENTIONED UPR-LVL WAVE WILL GRADUALLY DRIFT ACRS NY/PA MON INTO MON NGT...WHILE WEAKENING. THIS SYSTEM SHOULD THEN MINOR OUT AND DRIFT TO OUR S ON TUE. SINCE...THUS FAR...MOST OF THE CONVECTIVE ACTIVITY HAS OCCURRED ON THE ERN/SERN SIDES OF THIS SHRT WV...WE FEEL GOOD ABT OUR FCST OF SCTD SHRA/ISOLD TSRA MON AND MON NGT...WITH A DECREASE IN COVERAGE TUE. INSTAB MAY BE SOMEWHAT LESS ON MON...AS OPPOSED TO THIS AFTN...WITH MORE CLDS/SLIGHTLY COOLER TEMPS...BUT A FEW TSTMS STILL SEEM PLAUSIBLE...AND THUS WE LEFT THIS MENTION IN THE FCST. CLDS SHOULD BREAK TO ALLOW INCREASING SUNSHINE TUE...AS SOME DVM DEVELOPS TO THE REAR OF THE AFOREMENTIONED SHRT WV. GIVEN A VERY WARM AMS STILL IN PLACE...TEMPS SHOULD AGAIN CLIMB WELL INTO THE 70S. WED COULD BE THE WARMEST DAY OF THE WEEK...WITH BUILDING HEIGHTS AT ALL LVLS...AND A FAIR AMT OF SUN. TEMPS IN THE 75-80 RANGE SEEM LIKELY...MAYBE EVEN INTO THE LWR 80S IN NORMALLY WARMER LAKE PLAIN AREAS. THE MODELS IN GENERAL...HAVE NOT BEEN ABLE TO KEEP UP WITH THE UNSEASONABLE WARMTH...AND WE`VE GONE ABV ANY AVAILABLE MACHINE TEMPS...BY SEVERAL DEGS AT LEAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 4 AM UPDATE... NOT MUCH CHANGE. THURSDAY ONE MORE DAY IN THE 70S. STILL QUESTIONS ON FRIDAY AND SATURDAY ON HOW MUCH COLD AIR COMES IN WITH THE BACK DOOR FRONT. BLENDED THE COLDER GMOS WITH THE HPC GUIDANCE. 4 PM UPDATE...THE OVERALL THEME OF A WARM START TO THE LONG TERM PERIOD...FOLLOWED BY GRADUALLY "COOLER" TEMPS...BUT STILL REMAINING ABOVE AVERAGE CONTINUES. THE BIGGEST DIFFERENCE OVER THE LAST 24 HOURS HAS BEEN THE LONG RANGE MODELS NAMELY THE EURO/GFS/CANADIAN...ALL NOW SHOW A BACKDOOR COLD FRONT MOVING INTO THE AREA LATE THURSDAY. ASIDE FROM AN INCREASE IN CLOUDS AND MAYBE A LATE DAY SHOWER THURSDAY...HIGHS STILL LOOK TO BE VERY WARM AHEAD OF THE FRONT OR WELL INTO THE 70S ONCE AGAIN. THE DIFFERENCE WITH THE FRONT WILL BE COOLER TEMPS FRIDAY...ESPECIALLY ACROSS THE FAR NORTH...WITH MUCH LESS OF AN IMPACT FARTHER SOUTH INTO NEPA. WE MAY SEE A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT THIS DAY DUE TO THE COOLER AIR MOVING IN FROM THE NORTHEAST. IN ADDITION TO BEING SLIGHTLY COOLER...BEHIND THE FRONT DRIER WEATHER WILL BUILD IN FRIDAY INTO EARLY SATURDAY BEFORE WE MAY SEE THE INFLUENCES OF A CUT OFF LOW LATE SATURDAY INTO SUNDAY. TEMPERATURES AT THIS POINT IN THE FORECAST ARE VERY UNCERTAIN...BUT BASED ON THE LAST FEW MODEL RUNS IT APPEARS THAT WHILE IT WILL BE COOLER OVER THE UPCOMING WEEKEND THAN OUR RECENT STRETCH...WE WILL REMAIN QUITE MILD FOR THIS TIME OF THE YEAR. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... 2 AM UPDATE... OVERALL VFR WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD. AN UPPER LEVEL DISTURBANCE IN THE ATMOSPHERE IS BRINGING ISOLATED LIGHT SHOWERS INTO THE SYR AND RME VICINITY BUT NOT ENOUGH THERE TO PUT IN THE TAFS. REST OF SITES COULD HAVE SOME MVFR VSBYS AROUND SUNRISE...11Z THIS MORNING. MID CLOUDS FOR THE ENTIRE PERIOD. SOME MORE SHOWERS POSSIBLE THIS AFTERNOON BUT MOST LIKELY WILL NOT CAUSE ENOUGH MVFR TO INCLUDE AT THIS TIME. SHOWERS WILL BE ORIENTED NORTH TO SOUTH AND WILL MOVE SLOWLY EAST TODAY INTO THE EVENING. LIGHT AND VARIABLE WINDS EARLY THIS MORNING. SOUTH WINDS 3 TO 6 KTS DURING THE DAY TODAY. BACK TO LIGHT AND VARIABLE TONIGHT. .OUTLOOK... LATE TONIGHT...MVFR VSBY FOG AGAIN POSSIBLE. TUE TO WED NGT...GNRL VFR DURING THE DAY AND MVFR FOG LATE AT NIGHT. THU...VFR. POSSIBLE MVFR IN SHOWERS ASSOCIATED WITH A COLD FRONT. THU NGT TO FRI...VFR. MVFR FOG POSSIBLE LATE THU NGT TO FRI MORNING. && .FIRE WEATHER... 230 AM MON UPDATE... LOW FIRE THREAT WITH RELATIVE HUMIDITIES TOO HIGH AND TOO LITTLE WIND MOST OF THE WEEK. IN ADDITION SHOWERS TODAY... TONIGHT...AND POSSIBLY THURSDAY TO WET THE FUELS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MLJ NEAR TERM...HEDEN/MLJ/RRM SHORT TERM...MLJ LONG TERM...HEDEN/TAC AVIATION...TAC FIRE WEATHER...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1236 AM EDT MON MAR 19 2012 .SYNOPSIS... A SOUTHERLY FLOW OF UNSEASONABLY WARM AIR WILL CONTINUE FOR THE NEXT SEVERAL DAYS. AN UPPER LEVEL DISTURBANCE WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM TONIGHT INTO MONDAY NIGHT. OTHERWISE...THOUGH...RAIN FREE CONDITIONS ARE EXPECTED THROUGH MIDWEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1230 AM UPDATE...LOCAL RADAR SHOWS ISOLATED LIGHT SHOWERS REDEVELOPING FROM THE CENTRAL SOUTHERN TIER ACROSS THE FINGER LAKES TO THE WESTERN MOHAWK VALLEY. HRRR AND LOCAL WRF INDICATE THIS ACTIVITY WILL PERSIST THROUGH THE OVERNIGHT PERIOD, ALTHOUGH ISOLATED, IN AN AREA OF HIGHER SFC DEW POINTS LOW/MID 50S. ADJUSTED POPS TO REFLECT ISOLATED ACTIVITY OVERNIGHT FROM ABOVE MENTIONED AREA WITH SLIGHT PROGRESSION EAST. NO OTHER CHANGES. 10 PM UPDATE...AN AREA OF BROKEN TO ISOLATED SHOWERS ON A LINE FROM SOUTHERN STEUBEN COUNTY NORTHEAST THROUGH THE FINGER LAKES CONTINUES TO FALL APART. EXPECT THIS TREND TO CONTINUE THROUGH MIDNIGHT. ASIDE FROM THIS PRECIPITATION...A QUICK LOOK AT THE REGIONAL RADAR SHOWS THAT WE SHOULD BE IN FOR A MAINLY DRY NIGHT ONCE WE GET RID OF THE SHOWERS CURRENTLY IN PLACE. THE NEXT AREA OF SHOWERS ACROSS OHIO IS IN DIRECT ASSOCIATION WITH A H5 SHORT WAVE ACROSS EASTERN OH. THIS SHORT WAVE IS ESSENTIALLY IN THE MIDDLE OF TWO H5 RIDGES (ONE TO OUR EAST OVER NEW ENGLAND AND ANOTHER ACROSS THE WESTERN OHIO VALLEY). DUE TO THIS...THE UPPER LEVEL FLOW IS VERY WEAK AND WE DO NOT EXPECT ANY LIFTING MECHANISM TO MOVE OUR WAY FOR THE REST OF THE OVERNIGHT. ON MONDAY AS THIS SHORT WAVE MOVES A BIT CLOSER AND WE GET SOME DAYTIME HEATING...SHOWER AND THUNDERSTORM CHANCES WILL BODILY INCREASE FROM MID-MORNING ON. 7 PM UPDATE...INCREASED CHANCE POPS TO LIKELY FROM THE FINGER LAKES INTO THE WESTERN MOHAWK VALLEY FOR THE NEXT FEW HOURS. AFTER WE LOSE OUR DAYTIME HEATING THE COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH AND WHILE A FEW RUMBLES OF THUNDER ARE STILL POSSIBLE...THIS THREAT SHOULD ALSO GO DOWN. EXPECT THAT THE AREA OF PRECIP NOW WILL NOT SHIFT TOO MUCH FARTHER SOUTH AND EAST SO THROUGH EARLY TONIGHT THE AREAS SEEING RAIN NOW WILL REMAIN THE MOST AT RISK. 3 PM UPDATE... SCTD SHRA/TSRA ARE POPPING UP LATE THIS AFTN ACRS WRN PA/NY...AS AN UPR-LVL WAVE APPROACHES...AND ACTS ON EXISTING INSTAB (ML CAPES IN THE 500-750 RANGE). WE EXPECT THIS ACTIVITY TO DRIFT VERY SLOWLY EWD...AND INTO OUR WRN/NRN ZNS IN THE 21-00Z TIME FRAME. ALTHOUGH THE AMS WILL CERTAINLY STABILIZE DIURNALLY AFTER SUNSET...THE HISTORY OF THIS SHRT WV HAS FEATURED EMBEDDED TSRA...EVEN IN THE OVERNIGHT PDS. THUS...WE`LL CONTINUE TO ADVERTISE SCTD SHRA AND ISOLD TSRA...MAINLY FROM THE FINGER LKS/CNTRL SRN TIER AREAS...UP ACROSS KSYR METRO...AND INTO THE MOHAWK VLY/SRN TUG HILL RGNS. AREAS TO THE S AND E OF KBGM SHOULD STAY MOSTLY RAIN-FREE OVERNIGHT. GIVEN AN INCREASE IN CLDS FROM THE W TNT (LESS RADIATIONAL COOLING)...AND A LOW-LVL TRAJECTORY MORE FROM THE S AND SW...AS OPPOSED TO THE SE...WE FEEL THE EXTENT OF MARINE LYR ST/FOG WILL BE MUCH LESS...AS COMPARED TO RECENT NGTS. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... 310 PM UPDATE... MODEL AGREEMENT REMAINS GOOD...ON THE SYNOPTIC SCALE...THAT THE ABV MENTIONED UPR-LVL WAVE WILL GRADUALLY DRIFT ACRS NY/PA MON INTO MON NGT...WHILE WEAKENING. THIS SYSTEM SHOULD THEN MINOR OUT AND DRIFT TO OUR S ON TUE. SINCE...THUS FAR...MOST OF THE CONVECTIVE ACTIVITY HAS OCCURRED ON THE ERN/SERN SIDES OF THIS SHRT WV...WE FEEL GOOD ABT OUR FCST OF SCTD SHRA/ISOLD TSRA MON AND MON NGT...WITH A DECREASE IN COVERAGE TUE. INSTAB MAY BE SOMEWHAT LESS ON MON...AS OPPOSED TO THIS AFTN...WITH MORE CLDS/SLIGHTLY COOLER TEMPS...BUT A FEW TSTMS STILL SEEM PLAUSIBLE...AND THUS WE LEFT THIS MENTION IN THE FCST. CLDS SHOULD BREAK TO ALLOW INCREASING SUNSHINE TUE...AS SOME DVM DEVELOPS TO THE REAR OF THE AFOREMENTIONED SHRT WV. GIVEN A VERY WARM AMS STILL IN PLACE...TEMPS SHOULD AGAIN CLIMB WELL INTO THE 70S. WED COULD BE THE WARMEST DAY OF THE WEEK...WITH BUILDING HEIGHTS AT ALL LVLS...AND A FAIR AMT OF SUN. TEMPS IN THE 75-80 RANGE SEEM LIKELY...MAYBE EVEN INTO THE LWR 80S IN NORMALLY WARMER LAKE PLAIN AREAS. THE MODELS IN GENERAL...HAVE NOT BEEN ABLE TO KEEP UP WITH THE UNSEASONABLE WARMTH...AND WE`VE GONE ABV ANY AVAILABLE MACHINE TEMPS...BY SEVERAL DEGS AT LEAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 4 PM UPDATE...THE OVERALL THEME OF A WARM START TO THE LONG TERM PERIOD...FOLLOWED BY GRADUALLY "COOLER" TEMPS...BUT STILL REMAINING ABOVE AVERAGE CONTINUES. THE BIGGEST DIFFERENCE OVER THE LAST 24 HOURS HAS BEEN THE LONG RANGE MODELS NAMELY THE EURO/GFS/CANADIAN...ALL NOW SHOW A BACKDOOR COLD FRONT MOVING INTO THE AREA LATE THURSDAY. ASIDE FROM AN INCREASE IN CLOUDS AND MAYBE A LATE DAY SHOWER THURSDAY...HIGHS STILL LOOK TO BE VERY WARM AHEAD OF THE FRONT OR WELL INTO THE 70S ONCE AGAIN. THE DIFFERENCE WITH THE FRONT WILL BE COOLER TEMPS FRIDAY...ESPECIALLY ACROSS THE FAR NORTH...WITH MUCH LESS OF AN IMPACT FARTHER SOUTH INTO NEPA. WE MAY SEE A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT THIS DAY DUE TO THE COOLER AIR MOVING IN FROM THE NORTHEAST. IN ADDITION TO BEING SLIGHTLY COOLER...BEHIND THE FRONT DRIER WEATHER WILL BUILD IN FRIDAY INTO EARLY SATURDAY BEFORE WE MAY SEE THE INFLUENCES OF A CUT OFF LOW LATE SATURDAY INTO SUNDAY. TEMPERATURES AT THIS POINT IN THE FORECAST ARE VERY UNCERTAIN...BUT BASED ON THE LAST FEW MODEL RUNS IT APPEARS THAT WHILE IT WILL BE COOLER OVER THE UPCOMING WEEKEND THAN OUR RECENT STRETCH...WE WILL REMAIN QUITE MILD FOR THIS TIME OF THE YEAR. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AN UPPER LEVEL DISTURBANCE IN THE ATMOSPHERE IS BRINGING A LINE OF DIMINISHING SHOWERS INTO THE NORTHWESTERN TERMINALS THIS EVENING. THE SHOWERS WILL TAPER OFF BETWEEN 0Z AND 2Z, AND VFR RESTRICTIONS ARE ANTICIPATED. IT WILL BE A QUIET OVERNIGHT, WITH SOME LIGHT FOG FORMING TOWARD SUNRISE. VISIBILITIES OF 3SM TO 5SM WILL BE LIKELY BETWEEN 8Z AND 12Z. ANOTHER FRONT WILL SLIDE TOWARD THE REGION LATE MONDAY MORNING. ADDITIONAL SHOWERS ARE POSSIBLE BETWEEN 13Z AND 19Z, BUT VFR CONDITIONS ARE FORECAST TO PREVAIL. .OUTLOOK... TUE...GNRL VFR DURING THE DAY AND MVFR FOG LATE AT NIGHT. WED TO THUR...VFR. FRI...VFR. POSSIBLE MVFR IN LIGHT SHOWERS. && .FIRE WEATHER... 320 PM SUN UPDATE... SCTD SHRA/TSRA AND HIGHER RH VALUES WILL MITIGATE ANY FIRE WX CONDS MON. TUE SHOULD SEE LESS PCPN...BUT WINDS LOOK LGT AND VRBL...SO AGAIN A MINIMAL THREAT IS FORESEEN. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MLJ NEAR TERM...HEDEN/MLJ/RRM SHORT TERM...MLJ LONG TERM...HEDEN AVIATION...DJP FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
356 AM CDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH TUESDAY... MAIN CONCERNS THIS FORECAST PERIOD CENTER AROUND WINDS AND FIRE WEATHER. MODELS ARE IN BETTER AGREEMENT TODAY WITH LARGE-SCALE FEATURES AND USED A BLEND FOR DETAILS. CURRENTLY...THE UPPER LEVEL LONGWAVE TROUGH WAS OVER THE ROCKIES WITH SOUTHERLY FLOW ALOFT MOVING UP THE PLAINS STATES AND INTO SASKATCHEWAN AND MANITOBA. AT THE SURFACE...THE LOW WAS CENTERED OVER EXTREME SOUTHEASTERN MONTANA. SOUTHERLY SURFACE WINDS HAD INCREASED IN THE PAST COUPLE OF HOURS WITH WINDS IN THE SOUTHERN HALF OF THE STATE AT 15 TO 25 MPH WITH GUSTS TO AROUND 30 MPH AT TIMES. DEWPOINTS ACROSS THE STATE INDICATED DRY AIR MOVING INTO SOUTHWESTERN NORTH DAKOTA...WITH DEWPOINTS IN THE 20S AND 30S. IN THE CENTRAL AND EAST DEWPOINTS WERE IN THE 40S AND 50S. MODELS INDICATE THAT SOUTHERLY FLOW WILL INCREASE AND BY LATE MORNING SURFACE WINDS WILL BEGIN TO LINK WITH FAST-MOVING FLOW ALOFT TO H850...AND BY EARLY AFTERNOON THE ADIABATIC LINK WILL LIKELY REACH H700. EXPECTING SOUTHERLY WINDS TO REACH 40 MPH SUSTAINED IN PARTS OF SOUTHWESTERN NORTH DAKOTA...NAMELY SOUTH OF THE MISSOURI RIVER AND AS FAR EAST AS KILLDEER/DICKINSON/HETTINGER. THUS HAVE UPGRADED THE HIGH WIND WATCH TO A HIGH WIND WARNING IN THESE COUNTIES FOR LATE THIS MORNING THROUGH EARLY THIS EVENING. WIND SPEEDS ARE EXPECTED TO REACH AT LEAST 30 MPH FOR THE REST OF WESTERN AND MOST OF CENTRAL NORTH DAKOTA. UPGRADED THE HIGH WIND WATCH IN THESE AREAS TO A WIND ADVISORY WITH THE SAME TIMING AS IN THE WARNING. SEE FIRE WEATHER SECTION FOR DETAILS OF THE CURRENT RED FLAG WARNING. LOOKING AT HIGHS AROUND 60 FAR WEST TO AROUND 70 IN EASTERN PARTS OF CENTRAL NORTH DAKOTA. THE MODELS INDICATE THE SURFACE LOW WILL TRACK NORTHWARD INTO SOUTHEASTERN SASKATCHEWAN BY EVENING...AND INTO NORTHERN SASKATCHEWAN/MANITOBA BY TUESDAY MORNING. AS THE LOW MOVES NORTH...WINDS IN WESTERN NORTH DAKOTA WILL BECOME SOUTHWESTERLY LATE THIS AFTERNOON AND WESTERLY TONIGHT AND BRING IN COOLER AIR AS A COLD FRONT MOVES THROUGH. THE COLD FRONT SWEEPS ACROSS THE STATE TONIGHT. EXPECTING LOWS TONIGHT FROM THE UPPER 20S WEST TO THE 30S IN CENTRAL NORTH DAKOTA. COOLER TUESDAY WITH HIGHS IN THE 50S ACROSS THE REGION. WINDS WILL AGAIN INCREASE TUESDAY WITH SOUTHWEST WINDS IN RESPONSE TO THE FAST-MOVING SOUTHWEST FLOW ALOFT AND ANOTHER SURFACE LOW MOVING EAST ACROSS SOUTHERN CANADA IN RESPONSE TO ANOTHER VIGOROUS SHORTWAVE IN THE UPPER LEVEL FLOW. THE NORTHWEST HALF OF NORTH DAKOTA SHOULD SEE SOUTHWEST WINDS REACHING 25 MPH BY TUESDAY AFTERNOON. SEE THE FIRE WEATHER SECTION BELOW FOR IMPLICATIONS REGARDING THE FIRE WEATHER WATCH FOR TUESDAY. .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... WE BEGIN THE LONG TERM PERIOD WITH QUASI-ZONAL UPPER LEVEL FLOW OVER THE NORTHERN PLAINS AND A CUTOFF LOW IN THE SOUTHERN PLAINS. THE PERIOD WILL BEGIN ON A QUIET NOTE WITH DRY CONDITIONS TUESDAY NIGHT AND WEDNESDAY. UPPER LEVEL TROUGHING OVER THE EASTERN PACIFIC WILL RESULT IN DOWNSTREAM RIDGING OVER THE NORTHERN PLAINS AND WILL ALLOW THE AFOREMENTIONED UPPER LOW OVER THE SOUTHERN PLAINS TO DRIFT NORTH. BY THURSDAY AFTERNOON/EVENING...THE NORTHERN PERIPHERY OF MOISTURE ASSOCIATED WITH THE LOW WILL PUSH INTO THE FAR SOUTHERN COUNTIES OF THE LOCAL AREA. THIS WILL BRING A CHANCE OF SHOWERS LATE THURSDAY NIGHT AND FRIDAY TO AREAS ALONG AND EAST OF THE HIGHWAY 83 CORRIDOR. UPSTREAM RIDGING WILL PUSH THE SYSTEM OUT OF THE AREA BY FRIDAY EVENING. MODELS BEGIN TO DIVERGE ON THEIR SOLUTIONS AFTER THIS AND UNCERTAINTY INCREASES WITH THE UPPER LEVEL PATTERN INTO THE WEEKEND AND EARLY NEXT WEEK. GENERALLY SPEAKING...THE CENTRAL U.S. WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE...WITH NORTH DAKOTA ALONG THE PERIPHERY OF THIS RIDGE...SHORTWAVE ENERGY EXITING AN EASTERN PACIFIC/WESTERN U.S. TROUGH WILL SKIRT THE NORTHERN TIER COUNTIES. WILL THEREFORE CONTINUE A MENTION OF A SLIGHT CHANCE OF SHOWERS IN THE NORTH. LATE IN THE PERIOD...THE GFS IS QUICKER TO EJECT THE WESTERN U.S. TROUGH AND BRINGS INCREASING PRECIPITATION CHANCES OVER THE LOCAL AREA BY LATE SUNDAY. THE ECMWF/GEM AND ENSEMBLE MEMBERS FAVOR A SLOWER SOLUTION...KEEPING THE UPPER LOW OVER THE EASTERN PACIFIC THROUGH EARLY NEXT WEEK. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE EXTENDED PERIOD WITH WARMEST READINGS THURSDAY AND FRIDAY...THEN COOLING DOWN SATURDAY AND SUNDAY. && .AVIATION... STRONG LOW PRESSURE IS LIFTING NORTH THROUGH FAR EASTERN MONTANA WITH STRONG SOUTHERLY FLOW PUSHING NORTHWARD ACROSS WESTERN AND CENTRAL NORTH DAKOTA. FORECAST MODELS AND MET GUIDANCE IS ONCE AGAIN SUGGESTING POSSIBLE LOW CLOUD DEVELOPMENT OVER CENTRAL NORTH DAKOTA AROUND 12 UTC THIS MORNING. LATEST HRRR IS ALSO INDICATING AREAS OF LOW CLOUDS DEVELOPING AROUND 12 UTC. CURRENTLY NOTHING IS INDICATED FROM SURFACE OBS OR SATELLITE...ALTHOUGH HIGH CLOUDS ARE OBSCURING THE VIEW. WILL LIKELY BE ANOTHER GAME TIME DECISION ON WHETHER OR NOT TO MENTION A PERIOD OF MVFR-IFR CLOUDINESS AT BISMARCK...MINOT AND JAMESTOWN. MOISTURE POOLING NORTH OF THE SURFACE LOW IS CREATING AREAS OF FOG IN NORTHWEST NORTH DAKOTA...AND MAY NEED A MENTION OF FOG THIS MORNING AT WILLISTON. BY MID TO LATE MORNING...THE SURFACE LOW MOVES INTO NORTHEAST MONTANA AND DRY AIR WILL HAVE INTRUDED INTO ALL OF WESTERN AND CENTRAL NORTH DAKOTA. THE CONCERN FROM MID-LATE MORNING ON WILL BE WINDS WITH STRONG SOUTHERLY FLOW. SUSTAINED WINDS AROUND 40 MPH POSSIBLE IN DICKINSON...AND OVER 30 MPH ELSEWHERE FROM MID MORNING THROUGH LATE AFTERNOON. DIMINISHING WINDS WILL SHIFT WEST LATE AFTERNOON IN THE WEST...AND CLOSER TO MIDNIGHT AT JAMESTOWN. WRAP AROUND MOISTURE WILL MOVE INTO THE WEST THIS EVENING...WITH A POSSIBLE PERIOD OF MVFR CLOUDINESS AT DICKINSON AND WILLISTON...BUT AS THE SYSTEM LIFTS NORTH THE MOISTURE IS EXPECTED TO DISSIPATE BEFORE MOVING INTO BISMARCK AND MINOT. && .FIRE WEATHER... CRITICAL FIRE WEATHER PERIOD TODAY. THE 25 TO 40 MPH WINDS EXPECTED TODAY WITH GUSTS TO 50 MPH WILL COMBINE WITH LOW HUMIDITY TO BRING THE FIRE DANGER INTO THE EXTREME CATEGORY FOR ALL OF WESTERN AND MOST OF CENTRAL NORTH DAKOTA. DEWPOINTS ARE EXPECTED TO DROP INTO THE TEENS ACROSS MOST OF THE WESTERN HALF OF THE STATE TODAY...WITH DEWPOINTS IN THE 20S OVER THE REST OF CENTRAL NORTH DAKOTA WITH ONLY THE JAMES RIVER BASIN RETAINING HIGHER HUMIDITY WITH DEWPOINTS IN THE 30-45 RANGE. THUS MINIMUM RELATIVE HUMIDITY IS EXPECTED TO RANGE FROM 10 TO 25 PERCENT OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA...WITH 30 TO 35 PERCENT IN THE JAMES RIVER BASIN. ON TUESDAY DRY AIR IS AGAIN EXPECTED TO MIX DOWN TO THE SURFACE WITH DEWPOINTS FALLING INTO THE TEENS OVER ALL OF WESTERN AND MOST OF CENTRAL NORTH DAKOTA. MINIMUM RELATIVE HUMIDITY SHOULD BE IN THE 15 TO 25 PERCENT RANGE ACROSS THIS AREA...BUT WINDS IN THE SOUTH CENTRAL AND SOUTHEAST ARE EXPECTED TO REACH ONLY 10 TO 20 MPH. THUS HAVE DROPPED THESE COUNTIES FROM THE FIRE WEATHER WATCH. THE WEST AND NORTH CENTRAL COUNTIES SHOULD HAVE SUFFICIENT WINDS OF 25 MPH TO KEEP THE FIRE WEATHER WATCH GOING. NOT CONFIDENT ENOUGH TO UPGRADE TO A RED FLAG WARNING JUST YET. ALSO CHANGED TIMING OF THE WATCH TO REFLECT WHEN POSSIBLE RED FLAG CONDITIONS WOULD BE MET - MAINLY AFTERNOON TO EARLY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR NDZ001>005-009>013-017>023- 031>036-040>047-050. FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY EVENING FOR NDZ001>005-009>013-017>022-031>033-040-041-043. WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR NDZ001>005-009>013-019>023-025- 034>037-042-045>047-050. HIGH WIND WARNING FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR NDZ017-018-031>033-040-041-043- 044. && $$ SHORT TERM/FIRE WEATHER...JV LONG TERM/AVIATION....TWH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
206 AM EDT MON MAR 19 2012 .SYNOPSIS... AN UPPER LEVEL LOW WILL MOVE ACROSS THE AREA THIS EVENING. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE AREA THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE SIGNIFICANT RAINFALL HAS ENDED TO CANCELLED THE FLOOD WARNING EVEN THOUGH A FEW COUNTIES MAY STILL HAVE SOME MINOR FLOODING GOING ON. OTHERWISE SOME DECREASE IN CLOUDS OVER NORTHWEST OHIO AND SOME PATCHY DENSE FOG MAY DEVELOP. THE HRRR MODEL THINKS SOME SHOWERS COULD DEVELOP IN THIS AREA...KEPT IT DRY. OTHERWISE THE SHOWERS AND ISOLATED THUNDERSTORMS OVER EXTREME EASTERN OHIO AND NORTHWEST PA WILL SLOWLY MOVE EAST. ADJUSTED SOME OF THE LOWS DOWN BASED ON 9 PM READINGS. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... WELL ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH MID WEEK AS RIDGE BUILDS OVER THE AREA AND WILL BE THE DOMINANT FEATURE. CONDITIONS SHOULD BE PREDOMINATELY DRY THROUGH MID WEEK. DID MENTION CHC TSRA MONDAY AFTERNOON AS CAPES BUILD TO BETWEEN 1000 J/KG AND 1500. HOWEVER...LACK OF ANY KICKER COULD HINDER DEVELOPMENT OF AFTERNOON TSRA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A COOLER TREND FOR THE END OF THE WEEK WITH AN UPPER LOW MOVING INTO THE OHIO VALLEY AND A COLD FRONT COMING ACROSS THE GREAT LAKES. TIMING STILL IS AN ISSUE AND LIKELY THIS WILL TAKE A COUPLE/FEW DAYS TO CROSS THE REGION. MODEL DIFFERENCES ON PHASING BETWEEN NORTHERN SHORTWAVE AND THE MID U.S. UPPER LOW. EVEN MORE DIFFERENCE UPON TIMING OF ITS EXIT AND THE ARRIVAL OF HIGH PRESSURE...WITH THE ECMWF STILL THE FASTEST AND ALSO A LITTLE COOLER. TEMPERATURES WILL REMAIN ABOVE NORMAL...WILL JUST BE ABOUT 15 OR SO DEGREES COOLER FOR HIGHS THIS WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... HIGH LOW LEVEL MOISTURE WILL MAKE FOG A CONCERN IN AREAS WHERE SKIES CLEAR OUT TONIGHT. TOL HAS ALREADY DROPPED TO A QUATER MILE WITH LIGHT EASTERLY FLOW BRINGING MOISTURE OFF LAKE ERIE WITH OTHER VISIBILITIES ACROSS NORTHERN OHIO STARTING TO FALL. SATELLITE IMAGERY SHOWS CLOUDS IN THE 4-8K RANGE INCREASING ACROSS NW OHIO AND IF THIS CAN BECOME WIDESPREAD ENOUGH THEN IT MAY HELP VISIBILITIES FROM DROPPING TO LIFR. FURTHER EAST CLOUDS AND SCATTERED SHOWERS LINGER AND WILL BE SLOWER TO CLEAR AND SEE FOG DEVELOPMENT. FOG IS EXPECTED TO BURN OFF AS SOUTHWESTERY FLOW DEVELOPS ON MONDAY MORNING. A FEW SHOWERS WILL ONCE AGAIN BE POSSIBLE ON MONDAY AFTERNOON AND POSSIBLY EVEN A THUNDERSTORM BUT COVERAGE WAS TOO LOW TO INCLUDE IN MOST OF THE TAFS AT THIS TIME. OUTLOOK...NON VFR POSSIBLE IN MORNING BR TUESDAY AND WEDNESDAY. NON VFR POSSIBLE IN SHOWERS ON THURSDAY AND FRIDAY. && .MARINE... OUTSIDE OF ISOLATED/SCATTERED THUNDERSTORMS...LAKE CONDITIONS QUIET. LIGHT FLOW WILL CONTINUE THROUGH THE WEEK AND FOR THE MOST PART WINDS WILL BE SOUTHERLY. THERE IS A FRONT THAT WILL MOVING ACROSS THE CENTRAL LAKES MID WEEK AND MAY WANT TO SLIP ACROSS LAKE ERIE THURSDAY...BUT TIMING OF FEATURES LATE THIS WEEK COMPLICATED BY A CUT OFF LOW THAT WILL BE MAKING ITS WAY SLOWLY TO THE OHIO VALLEY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...DJB NEAR TERM...KIELTYKA SHORT TERM...DJB LONG TERM...OUDEMAN AVIATION...KEC MARINE...OUDEMAN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1120 PM MDT SUN MAR 18 2012 .AVIATION...06Z TAFS DYNAMIC SITUATION IN PLACE OVERNIGHT WITH LOW OVER SOUTHEAST MT THAT WILL MOVE INTO ND. INITIAL TROUGH/COLD FRONT IS SURGING ONTO THE SD PLAINS WITH GUSTY SOUTH WINDS AHEAD OF IT AND GUSTY SOUTHWEST WINDS BEHIND IT. SECONDARY COLD FRONT FROM LOW INTO SOUTHERN MT WILL SURGE SOUTHEAST OVERNIGHT THROUGH MONDAY WITH STRONG SOUTHWEST WINDS AHEAD OF IT AND VERY WINDY NORTHWEST WINDS BEHIND IT. LEFTOVER -SHRA TONIGHT WITH SOME POST FRONTAL -SHRA POSSIBLE MONDAY. VFR CONDITIONS WILL DOMINATE WITH SOME SC AROUND 4KFT AND BKN-OVC MID/HIGH CLOUDS. && .PREV DISCUSSION... /ISSUED 823 PM MDT SUN MAR 18 2012/ UPDATE...02Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST MT AND COLD FRONT INTO CENTRAL CO. WATER VAPOUR HAD SHORTWAVE OVER SOUTHEAST WY/NE PANHANDLE...ON THE NOSE OF A 110KT JET. THIS WAVE WILL RAPIDLY MOVE NORTH TONIGHT PUSHING COLD FRONT INTO THE CWA FROM THE WEST. AHEAD OF IT...GUSTY SOUTHWEST WINDS WILL CONTINUE BUT DIURNAL BOUNDARY LAYER EFFECTS ARE STARTING TO DECOUPLE 50KT LOW LEVEL JET FROM MIXED LAYER. THUS WILL ALLOW WIND HEADLINES TO EXPIRE ON SCHEDULE AT 03Z. MOIST TONGUE HAD 50-PLUS DEW POINTS OVER SOUTH CENTRAL SD INTO CENTRAL NE. NARROW AXIS OF INSTABILITY ALLOWING FOR SOME CONVECTION. FURTHER WEST...SOME -SHRA NOTED WITH MAIN SYNOPTIC FORCING...BUT LAPSE RATES STEEP ENOUGH TO LEAVE SMALL CHANCE OF THUNDER IN THERE THROUGH 06Z. WITH THESE TRENDS IN MIND AND HRRR SOLUTIONS...WILL BRING SOME POPS CWA-WIDE THIS EVENING AND ACROSS THE NORTH THROUGH EASTERN PORTIONS OF THE CWA OVERNIGHT. FIRE WEATHER...RELATIVE HUMIDITIES WILL RECOVER ENOUGH TO ALLOW RED FLAG WARNING TO EXPIRE ON-TIME AT 03Z. PREV DISCUSSION... /ISSUED 653 PM MDT SUN MAR 18 2012/ UPDATE...00Z SURFACE ANALYSIS HAD LOW OVER CENTRAL WY WITH DECENT GRADIENT OVER THE CWA. BEST GRADIENT FROM SOUTHWEST THROUGH SOUTH CENTRAL SD WHERE CONTINUED MIXING IS ALLOWING VERY WINDY CONDITIONS TO PERSIST. FURTHER NORTH WHERE CI/CS SHIELD DROPPED IN DURING THE AFTERNOON...WINDS ARE JUST BREEZY/WINDY...SO WILL CANCEL WIND ADVISORY FOR THOSE AREAS. 00Z KUNR SOUNDING SHOWED IMPRESSIVE LAPSE RATES AGAIN. WATER VAPOUR HAD MAIN SHORTWAVE ENERGY OVER NORTH CENTRAL CO/SOUTHEAST WY ON NOSE OF 110KT JET. THIS WILL PUSH LOW NORTHEAST TONIGHT...ALLOWING COLDER AIR TO FILTER OVER WESTERN AREAS. STRONG WIND FIELD MAY SUPPORT GUSTY WINDS NEAR ANY -SHRA/-TSRA THAT DEVELOP OVER NORTHEASTERN WY AND SOUTH CENTRAL SD TONIGHT. PREV DISCUSSION... /ISSUED 234 PM MDT SUN MAR 18 2012/ TONIGHT THROUGH TUESDAY NIGHT DEEP LONG WAVE WESTERN CONUS TROUGH CONTINUES ITS SLOW MARCH TO THE NE...WITH SFC PRESSURE FALLS ONGOING ACROSS WY AND SOUTHERN MT AS A PORTION OF THE UPPER TROUGH FRACTURES AND BEGINS TO ADVECT NE. THIS STRONG IMPULSE WILL MERGE WITH A NW CONUS ADVANCING TROUGH AND SUPPORT SFC LOW ADVECTION NE INTO THE CANADIAN PLAINS. HEIGHT FALLS CONTINUE INTO WY WITH DESTABILIZATION ONGOING THERE PER LL WARMING AND UPPER LEVEL COOLING. A FEW HIGH BASED SHRA AND ISOLD TS HAVE DEVELOPED FARTHER WEST OUTSIDE THE FA...WHERE A LITTLE BETTER UPPER SUPPORT IS IN PLACE. SFC BASED INSTABILITY WILL CONTINUE TO INCREASE THIS AFTERNOON OVER NE WY...WITH THE SFC TROUGH EXPECTED TO APPROACH THE REGION...SUPPORTING LOW CHANCE POPS INTO THIS EVENING THERE...AND POSSIBLY INTO THE WESTERN BLACK HILLS. OTHERWISE...WARM WINDY CONDITIONS ARE DEVELOPING ACROSS THE REGION...AS MIXING HEIGHTS INCREASE AND LL FLOW RESPONDS TO THE HEIGHT FIELD. WINDS WILL CONTINUE TO INCREASE THROUGH THE AFTERNOON WITH WIND ADV CRITERIA EXPECTED TO BE REACHED LATE THIS AFTERNOON AND EARLY EVENING. STRONG 125+ KNOT UPPER LEVEL JETLET ASSOCIATED WITH THE MAIN UPPER TROUGH OVER THE SW CONUS...WILL ADVECT NNE TOWARD THE REGION TONIGHT...WITH THE NOSE OF THE UPPER JET EXPECTED TO ADVECT OVER THE FA. LEFT EXIT REGION INDUCED UPWARD ASCENT WILL HELP IN FURTHER DEEPENING THE SFC LOW...IN ADDITION TO ACCENTUATING THE LLJ. FORECAST MODELS ARE STILL INDICATING INCREASING DEEPER MOISTURE OVER SOUTH CENTRAL SD...GIVEN H85 THETA-E RISES INTO THE 320-330K RANGE THROUGH 06Z...AHEAD OF THE LEAD SFC TROUGH. GIVEN THE POSITION OF THE UPPER JET RIGHT EXIT REGION/INCREASING LL MOISTURE/AND INCREASING LARGE SCALE ASCENT...CANNOT RULE OUT AN ISOLATED SHRA OR TS OVER THE FAR SE. HAVE INCORPORATED A 6 HOUR PERIOD OF TS MENTION THERE. OTHERWISE...DIURNALLY DRIVEN CONVECTION CHANCES OVER NE WY WILL WANE THROUGH EVENING. AFOREMENTIONED UPPER IMPULSE WILL PHASE WITH A NORTHERN STREAM COUNTERPART AND SUPPORT A COLD FRONT INTO THE REGION MONDAY. CONTINUED WEAK UPGLIDE OVER WESTERN SD MAY SUPPORT A LIGHT SHOWER OVER THE FAR SE...WITH CONVECTIVE SHOWERS EXPECTED TO DEVELOP ALONG AND AHEAD OF THE SFC COLD FRONT IN NE WY...LIKELY DIURNALLY ENHANCED. COOLING PROFILES SUGGEST RAIN MAY MIX WITH SNOW DURING THE AFTERNOON. HOWEVER...SFC TEMPS IN THE 40S WILL PRECLUDE ACCUMS. SHOWER ACTIVITY WILL WANE THROUGH EVENING OVER NE WY AND THE WESTERN/NORTHERN BLACK HILLS...WITH ANY RESIDUAL SHRA TRANSITIONING TO SNOW. SOME LIGHT ACCUMS ARE POSSIBLE. OTHERWISE...SOUTHERLY WINDS WILL BE GUSTY AHEAD OF THE SFC COLD FRONT MON...WITH WINDS INCREASING TO 20 TO 30 MPH OVER THE NORTHERN HALF OF WESTERN SD. WIND ADV CRITERIA MAY BE REACHED CLOSER TO THE ND BORDER GIVEN SIG PRESSURE FALLS ONGOING OVER NE MT. SFC COLD WILL PUSH EAST OF THE REGION...COMING THROUGH DRY OVER SD AS THE MAIN LOBE OF LARGE SCALE ASCENT SHIFTS NORTH INTO MT/ND/SK. DRY BUT STILL MILD WEATHER IS ON TRACK FOR TUES...WITH MOSTLY CLEAR SKIES EXPECTED. EXTENDED...A MAINLY DRY AND MILD WEATHER PATTERN IS ANTICIPATED FOR THE MIDDLE AND LATTER PART OF THE WEEK. HOWEVER...AN UPPER LEVEL LOW IS PROGGED TO BE IN PLACE OVER THE SOUTHERN HIGH PLAINS MIDWEEK AND SLOWLY MOVE NORTHEAST ACROSS THE PLAINS LATE IN THE WEEK. DEPENDING ON THE ULTIMATE MOVEMENT OF THE LOW...THERE COULD BE A CHANCE FOR SHOWERS OVER MAINLY SOUTHEASTERN PORTIONS OF THE CWA THURSDAY INTO FRIDAY. VARIOUS MEDIUM RANGE MODELS DIFFER ON TIMING AND MOVEMENT OF THE SYSTEM WITH A STRONG RIDGE TO THE EAST OF THE REGION. GFS BRINGS IT THE FURTHEST NORTH...WITH SHOWERS POSSIBLE OVER PORTIONS OF SOUTHWESTERN INTO CENTRAL SD. WILL GO WITH THE CONSENSUS OF THE MODELS AND KEEP DRY FOR NOW. OTHERWISE...TEMPS WILL BE WELL ABOVE AVERAGE THROUGH THE PERIOD...WITH HIGHS IN THE 60S AND 70S ON MOST DAYS...A BIT COOLER OVER THE BLACK HILLS. FIRE WEATHER...RED FLAG CONDITIONS HAVE DEVELOPED ACROSS MUCH OF NORTHEASTERN WY AND WESTERN SD THIS AFTERNOON AS WINDS INCREASE AND HUMIDITIES DROP TO NEAR OR BELOW 15 PERCENT. THESE CRITICAL FIRE WEATHER CONDITIONS WILL PERSIST INTO EARLY THIS EVENING BEFORE HUMIDITIES SLOWLY RISE AND WINDS GRADUALLY DECREASE. ON MONDAY...GUSTY SOUTHWESTERLY WINDS WILL DEVELOP AHEAD OF AN APPROACHING COLD FRONT. TEMPERATURES WILL BE LOWER...BUT A VERY DRY AIRMASS IN PLACE WILL DROP RELATIVE HUMIDITIES TO AROUND 15 PERCENT ACROSS MUCH OF WESTERN AND SOUTH CENTRAL SOUTH DAKOTA IN THE AFTERNOON. CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TO DEVELOP OVER THESE AREAS IN THE AFTERNOON AND PERSIST UNTIL AROUND SUNSET. A COLD FRONT WILL FINALLY MOVE THROUGH THE AREA MONDAY NIGHT... BRINGING LOWER TEMPERATURES AND HIGHER HUMIDITIES FOR TUESDAY. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...RED FLAG WARNING FROM 11 AM TO 8 PM MDT MONDAY FOR BADLANDS AREA- CENTRAL SOUTH DAKOTA PLAINS-NORTHERN BLACK HILLS- NORTHWESTERN SOUTH DAKOTA PLAINS-SOUTH CENTRAL SOUTH DAKOTA- SOUTHERN BLACK HILLS-SOUTHWESTERN SOUTH DAKOTA. WY...NONE. && $$ SHORT TERM...WFO UNR LONG TERM....WFO UNR AVIATION...HELGESON
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1214 AM CDT MON MAR 19 2012 .UPDATE... AVIATION DISCUSSION UPDATED FOR 06Z TAF ISSUANCE. EXCEPTIONALLY WARM EVENING CONTINUES THIS EVENING AS STRONG LLV SOUTHERLY FLOW CONTINUES. ABR STILL 72F AS OF THIS WRITING WITH NO REAL END IN SITE TO AT LEAST MODERATE SOUTH WINDS. RAISED OVERNIGHT LOWS TO THE WELL PERFORMING BCCONSRAW GUIDANCE LEVELS BUT THEY MAY NOT BE WARM ENOUGH. 53F IS THE ALL TIME MARCH RECORD FOR HIGHEST MINIMUM TEMPERATURE AT ABERDEEN. WITH SOUTH WINDS CONTINUING...THANKS TO A STRENGTHENING LLJ... AND HIGH CLOUDS INCREASING FROM THE SOUTH...EXPECT THAT TEMPS WILL STRUGGLE TO FALL BELOW 60F BY MORNING. ALSO ADDED SLIGHT CHANCE FOR THUNDERSTORMS OVER THE SOUTHWEST ZONES FOR THE REMAINDER OF THE NIGHT GIVEN LATEST HRRR RUNS AND RADAR OBSERVATIONS SHOWING THUNDERSTORMS PROPAGATING NWD THROUGH NORTH CENTRAL NEBRASKA. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT MODELS ARE NOT BEING OVERLY HELPFUL WITH THE LACK OF CONSISTENCY ON THE CURRENT ROCKY MOUNTAIN LOW AND THE ASSOCIATED COLD FRONT THAT WILL MOVE THROUGH THE DAKOTAS ON MONDAY. THIS DEVELOPING LOW WILL PROGRESS NORTH INTO CANADA AND THEN EAST TRACKING A 65 KT LLJ OVER THE DAKOTAS TONIGHT. KEPT A SMALL CHANCE OF TSTORMS ACROSS CODINGTON/HAMLIN/DEUEL COUNTIES LATE TONIGHT AS THE JET PROGRESSES FARTHER EAST. WITH ABUNDANT LOW LEVEL MOISTURE IN PLACE AND ABOUT 1000 J/KG CAPE SOMETHING MAY KICK OFF. DID NOT PUT ANY TSTORMS FARTHER WEST DUE TO LACK OF MOISTURE THIS EVENING. AHEAD OF THE FRONT ON MONDAY THERE ARE TWO AREAS OF CONCERN. ONE WILL BE THE STRONG SOUTHERLY WINDS. WITH PRESSURE FALLS OF AROUND 15 TO 20 MB AND SOME CAA THIS MAY WARRANT A WIND ADVISORY...BUT WILL PUNT THIS DECISION TO THE NEXT SHIFT. AS THE WINDS INCREASE...RH WILL ALSO DROP WEST OF THE MISSOURI RIVER TO 15 TO 20 PERCENT. SO THE SECOND CONCERN WILL BE TO CONSIDER ANOTHER RFW FOR MONDAY...THOUGH FARTHER WEST THAN WHAT IS IN PLACE TODAY. SOME MORE TSTORMS ARE POSSIBLE ON MONDAY OUT AHEAD OF THE FROPA WITH SHOWERS LINGERING BEHIND. TEMPERATURES WILL FALL OFF A BIT WITH ADDED CLOUD COVER TO AROUND 70 DEGREES ACROSS THE REGION. BEHIND THE COLD FRONT HIGHS WILL REACH ONLY INTO THE UPPER 50S ON TUESDAY. .LONG TERM...WEDNESDAY THROUGH SUNDAY MAIN FEATURE TO WATCH IN THE EXTENDED PERIOD IS THE CUTOFF LOW THAT WOBBLES ACROSS THE CENTRAL PLAINS. RECENT MODEL RUNS HAVE BROUGHT THIS FEATURE A BIT FARTHER NORTH WHICH ALLOWS OUTER RAIN BAND TO REACH THE EASTERN CWA. SLIGHT CHANCE POPS HAVE BEEN INSERTED ACROSS THE EASTERN CWA THURSDAY INTO FRIDAY. OTHERWISE...THIS IS ABOUT THE ONLY FEATURE TO DEAL WITH DURING THE FORECAST PERIOD. TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL WITH READINGS IN THE 60S FOR MOST LOCATIONS. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS FOR KABR AND KATY...LOW LEVEL MOISTURE WILL MAKE A RETURN LATER TONIGHT SO EXPECT AREAS/PATCHY OF MVFR/IFR CIGS TO DEVELOP ONCE AGAIN AFTER APPROXIMATELY 09Z MONDAY. THESE CIGS SHOULD GRADUALLY DISSIPATE LATE MONDAY MORNING. BY MONDAY AFTERNOON AND EVENING...COULD SEE A FEW HIGH BASED -SHRAS/-TSRAS VCNTY KATY AND KABR. SOUTHERLY WINDS WILL INCREASE TO 25-35 KTS DURING THE AFTERNOON. FARTHER WEST AT KMBG AND KPIR...VFR CONDITIONS WILL PREVAIL THROUGH THE OVERNIGHT HOURS. AN ISOLATED -SHRA/-TSRA IS POSSIBLE EARLY TONIGHT VCNTY KPIR. STRONG SOUTHERLY WINDS WILL MAKE A RETURN MONDAY AFTERNOON. && .FIRE WEATHER... EXTREME FIRE CONDITIONS TOPS FORECAST PRIORITIES AGAIN TODAY. RECORD HIGH TEMPERATURES AGAIN POSSIBLE. A HUMID AIRMASS HAS SET UP IN THE EAST...WHILE WEST IS LESS HUMID AND SHOULD MIX OUT MORE EFFICIENTLY. THAT WILL CREATE A TIGHT NORTH TO SOUTH GRADIENT IN THE HUMIDITY TODAY...BETWEEN MOBRIDGE AND ABERDEEN AND BETWEEN PIERRE AND HURON. HIGH WINDS DEPEND ON THE DEGREE OF MIXING WITH STRONG WINDS ABOVE THE SURFACE ABLE TO MIX DOWN MORE EFFICIENTLY IN SOUTH CENTRAL COUNTIES. A LOW LEVEL JET WILL FORM AHEAD OF OUR SYSTEM TONIGHT...SO WHILE WINDS WILL LESSEN...THEY WILL REMAIN GUSTY...WHICH WILL ALSO KEEP TEMPERATURES MILD OVERNIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...SD SHORT TERM...WISE LONG TERM...TMT AVIATION...SD WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
433 AM CDT MON MAR 19 2012 .SHORT TERM (TODAY AND TONIGHT)...ISOLATED SHOWERS AND A COUPLE OF THUNDERSTORMS ARE ONGOING AT THE BEGINNING OF THE PERIOD ASSOCIATED WITH A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE MOST CONCENTRATED AREA OF SHOWERS AND STORMS HAS BEEN CLOSELY ASSOCIATED WITH A VORT MAX PROGGED WELL IN THE RUC MODEL. THE VORT MAX CONTINUES TO WEAKEN AS IT PUSHES TO THE NORTHWEST AND AS EXPECTED SHOWERS ARE WEAKENING AS WELL...WITH JUST A FEW LIGHTNING STRIKES REMAINING. THINK MOST OF TODAY WILL BE DRY ACROSS SOUTH TEXAS WITH JUST SOME ISOLATED LIGHT SHOWERS POSSIBLE WITH ADDITIONAL WEAK SHORT WAVES PROPAGATING AROUND MAIN TROUGH. MODEL SOUNDINGS INDICATE SIGNIFICANT CLEARING EVEN POSSIBLY IN WESTERN CWA. THIS WOULD ALLOW TEMPERATURES IN WEBB COUNTY TO INCREASE QUITE A BIT...CURRENTLY FORECASTING HIGHS IN THE MID 90S...BUT CAN`T DISCOUNT THE POSSIBILITY OF SOME AREAS GETTING A COUPLE OF DEGREES WARMER IF SKIES CLEAR. WITH LLJ NOT WEAKENING MUCH THROUGH THE DAY TODAY SHOULD MIX DOWN SOME GUSTS TO AROUND 40MPH THIS AFTERNOON SO HAVE ISSUED WIND ADVISORY FOR EASTERN HALF OF FORECAST AREA. THE FOCUS OF THE SHORT TERM FORECAST RESIDES IN THE POTENTIAL FOR THUNDERSTORMS TONIGHT AS THE COLD FRONT APPROACHES. INGREDIENTS LOOK DECENT FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY IN THE NORTHERN COUNTIES. SOUTHERN BRANCH OF SPLIT UPPER JET IS PROGGED A BIT FARTHER SOUTH TONIGHT THAN MODEL GUIDANCE WAS INDICATING LAST NIGHT. THIS SHOULD HELP THE CAUSE FOR DEVELOPMENT. WIND THREAT WOULD BE THE GREATEST SEVERE THREAT...AS 40-50KT LOW LEVEL JET WILL BE DIRECTLY OVERHEAD TONIGHT COINCIDING WITH THE THUNDERSTORMS. WITH SLIGHTLY SLOWER TIMING OF TROUGH...BEST CHANCE FOR SEVERE WILL BE AFTER MIDNIGHT ACROSS THE AREA...WITH THE NORTH AND NORTHEAST PART OF THE FORECAST AREA BEING THE MAIN TARGET. MODEL SOUNDINGS FOR VICTORIA INDICATE 1500J/KG CAPE OVERNIGHT...WITH LI/S AROUND -5. LAPSE RATES ARE ONLY MODERATE IN THIS REGION HOWEVER...IN THE 5-7C/KM RANGE. HAVE INCLUDED SEVERE WORDING ON FORECAST MAINLY FOR THE NORTHERN 2/3 OF THE FORECAST AREA. SPC HAS A SLIGHT RISK FOR SEVERE WEATHER ACROSS MOST OF THE FORECAST AREA...WITH A MODERATE RISK IN CENTRAL TEXAS. && .LONG TERM (TUESDAY THROUGH SUNDAY)...MAIN ISSUE THIS FORECAST PACKAGE IS WHETHER TO PLACE POPS IN AFTER TUESDAY AFTERNOON...WITH GENERALLY KEEPING SIMILAR POPS FOR TUESDAY AS ADVERTISED IN PREVIOUS PACKAGES. SPC HAS SLIGHT RISK ON BORDER OF AREA FOR DAY 2...AND WILL GENERALLY NOT SWAY FROM THIS). MODELS HAVE BEEN SHOWING THAT...AFTER THE MCS COMES ACROSS ON TUESDAY (NSSL AND NCEP WRF MODELS ARE KEEPING BIG CONVECTION TO THE NORTH THROUGH 12Z TUESDAY AND EXTRAPOLATION KEEPS THEM NORTH)...SOME DRYING OCCURS TUESDAY AFTERNOON UP TO 850 MB THEN SOME WRAP-AROUND MOISTURE FROM THE 700-300 MB LAYER COMES IN DURING THE LATE AFTERNOON THROUGH TUESDAY NIGHT (DRYING FROM WEST TO EAST AFTER MIDNIGHT TUESDAY EVENING). THIS IS A POTENT UPPER SYSTEM...AND MODELS FOR DAYS HAVE BEEN TOYING WITH POSSIBLE ADDITIONAL RAINFALL TUESDAY NIGHT. GIVEN THE FACT THE MODEL CONSENSUS IS SLOWING UPPER SYSTEM DOWN SOME...AND GUIDANCE IS GOING NEARLY LIKELY ON THE RAINFALL (THINK THIS IS OVER-DONE)...HAVE DECIDED TO INCLUDE POPS TUESDAY NIGHT MAINLY OVER THE EASTERN HALF OF CWFA. COULD EVEN SEE SOME THUNDER OVER THE EXTREME EASTERN AREAS/GULFMEX TUESDAY NIGHT. FARTHER WEST...SPRINKLES AT BEST. AFTER TUESDAY NIGHT...THINK UPPER SYSTEM WILL BE FAR ENOUGH NORTH AND SUFFICIENT DRYING OVER THE AREA TO END RAIN (GFS-MOS STILL HAS CHANCE POPS EASTERN AREAS BUT WILL IGNORE THIS). MODELS ARE RELATIVELY CONSISTENT UNTIL THE END OF THE WORK WEEK IN KEEPING A WEAK UPPER RIDGE OVER THE AREA...THEN DIVERGE OVER THE WEEKEND WITH THE GFS PUSHING THE RIDGE EAST AND MOVING A TROUGH TOWARD THE WESTERN CWFA LATE SUNDAY. THE ECMWF HOWEVER KEEPS THE RIDGE OVER THE AREA (BUT NOT BRINGING A BOUNDARY DOWN LIKE IT DID ON YESTERDAY`S 00Z RUN). FOR NOW...WILL KEEP THE FORECAST RAIN-FREE BUT BRING IN THE MOISTURE A LITTLE FASTER THAN BEFORE AND INCREASE OVERNIGHT TEMPERATURES SOME. OVERALL...TENDED TO GO MORE WITH THE WARMER FORECAST NUMBERS THROUGH THURSDAY MORNING...THEN OVERALL DID A CONSENSUS FORECAST BETWEEN THE ECMWF AND GFS SOLUTIONS FOR TEMPERATURES AND MOST OTHER PARAMETERS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 85 72 83 54 75 / 20 50 60 30 10 VICTORIA 81 70 74 53 72 / 40 70 80 40 10 LAREDO 94 68 83 53 81 / 20 40 20 10 10 ALICE 87 72 82 53 78 / 20 50 50 20 10 ROCKPORT 78 71 78 56 72 / 30 50 70 40 10 COTULLA 89 62 77 49 78 / 30 70 30 10 10 KINGSVILLE 87 71 83 52 77 / 20 50 50 30 10 NAVY CORPUS 79 71 81 57 73 / 20 50 70 40 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...GOLIAD...JIM WELLS...KLEBERG...LIVE OAK...NUECES...REFUGIO...SAN PATRICIO...VICTORIA. GM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. && $$ PZ/83...SHORT TERM GW/86...LONG TERM
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1208 AM CDT MON MAR 19 2012 .AVIATION... MVFR CIGS ARE DEVELOPING AND MOVING IN FROM THE SOUTH AND WILL INITIALIZE ALL TAF SITES WITH BKN020. MVFR CIGS WILL PERSIST INTO THE EARLY AFTERNOON HOURS MONDAY BEFORE LIFTING TO VFR HEIGHTS. SOUTH WINDS NEAR 15-20KT ARE EXPECTED TONIGHT AND WILL INCREASE TO 20-25KT MONDAY. MAIN FORECAST CHALLENGE IS TIMING OF CONVECTIVE EPISODES...WITH AT LEAST 2 ROUNDS OF STORMS LOOKING LIKELY. CONFIDENCE IS INCREASING ON A ROUND OF THUNDERSTORMS ARRIVING INTO THE METROPLEX AFTER 15Z/10AM. THIS ACTIVITY APPEARS TO BE DEVELOPING NOW DEVELOPING IN WEST TEXAS. RUC FORECASTS SURFACE TROUGH/DRY LINE TO REACH WESTERN TRACON BY 15Z WITH LINE OF STORMS HOLDING TOGETHER LONG ENOUGH TO REACH METROPLEX TAF SITES SHORTLY THEREAFTER. WILL SHOW PREVAILING TSRA FROM 15-19Z. THIS FIRST LINE OF CONVECTION SHOULD NOT BLOW THROUGH AND SCOUR THE AIRMASS...AND WITH THE DRY LINE HANGING BACK TO THE WEST ADDITIONAL SCATTERED STORMS ARE POSSIBLE IN THE MID AFTERNOON THROUGH EARLY EVENING HOURS. WILL SHOW VCTS IN THIS PERIOD SINCE CONFIDENCE IS NOT HIGH ENOUGH TO PICK A SPECIFIC TIME PERIOD TO PREVAIL TSRA. PRIMARY UPPER LEVEL FORCING DOES NOT ARRIVE UNTIL AROUND MIDNIGHT WHEN A SOLID LINE OF STORMS WILL LIKELY DEVELOP ALONG THE I-35 CORRIDOR AND SLOWLY ADVANCE EASTWARD. THE LOCATION OF THIS LINE WILL PUT TAF SITES PRIMARILY ON THE BACKSIDE OF THE CONVECTIVE COMPLEX AND THEREFORE EXPECT STEADY MODERATE TO HEAVY RAIN AND OCCASIONAL THUNDER PREVAILING LATE MONDAY EVENING THROUGH TUESDAY MORNING. TR.92 && .UPDATE... EXPANDED SLIGHT CHANCE POPS THROUGH WHOLE AREA THIS EVENING DUE TO ONGOING CONVECTION. MADE ONLY COSMETIC CHANGES TO REST OF THE GRIDS. 84 && .PREV DISCUSSION... /ISSUED 522 PM CDT SUN MAR 18 2012/ STRONG CAPPING INVERSION CENTERED AROUND 750 MB IS KEEPING NORTH TX RELATIVELY QUIET THIS AFTERNOON WITH JUST A FEW SPRINKLES OR LIGHT SHOWERS MOVING ACROSS THE SOUTH AND EAST CWA. AN AREA OF ENHANCE CU IS NOW DEVELOPING WEST OF ABILENE AND SAN ANGELO AS SHORTWAVE ENERGY MOVES ACROSS THIS REGION. INSOLATION HAS ALSO PUSHED TEMPERATURES WELL INTO THE 80S AND INCREASED SURFACE-BASED INSTABILITY...WHILE WEAKENING THE CAPPING INVERSION. A SLIGHT RISK REMAINS WEST OF OUR CWA AND DO NOT EXPECT TOO MUCH ACROSS NORTH TEXAS THROUGH THIS EVENING. NNE STORM MOTIONS AND EXPECTED CAP SHOULD KEEP AREA MAINLY HAZARD FREE. AS THE UPPER TROUGH SLOWLY DIGS AND CREEPS EAST OVER THE ROCKIES MONDAY MORNING...THE CAPPING INVERSION WILL GRADUALLY ERODE THROUGH MIDDAY AS A STRONGER LEAD SHORTWAVE LIFTS NORTHEAST FROM THE WEST TX BIG BEND AND OVER NORTH TX BY AFTERNOON. MEANWHILE...A SURFACE TROUGH WILL PUSH NEAR OR INTO OUR WESTERN COUNTIES AND ACT AS AN ADDITIONAL TRIGGER FOR NUMEROUS SHOWERS AND THUNDERSTORMS BY MIDDAY AND AFTER. BULK SHEAR PROFILES AND INSTABILITY...ALONG WITH THE FORCING SHOULD BE ENOUGH FOR SEVERE STORMS AS THE AREA WILL BE UNDER A SLIGHT RISK THROUGH MONDAY NIGHT. THE FIRST ROUND OF HEAVIER RAINFALL WILL OCCUR ACROSS CENTRAL AND EASTERN PARTS OF THE CWA BY MONDAY AFTERNOON. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS...THOUGH WARMER TEMPERATURES AND HIGHER DEW PTS ACROSS OUR SOUTHERN COUNTIES COULD RESULT IN A BRIEF WINDOW FOR A FEW TORNADOES PER BACKED LOW LEVEL FLOW AND LOWER LCL VALUES. THE NEXT AND MORE SIGNIFICANT ROUND OF HEAVIER RAINFALL OCCURS WITH ANOTHER SHORTWAVE ARRIVING JUST BEFORE SUNRISE TUESDAY MORNING. WITH PLENTIFUL GULF AND PACIFIC MOISTURE AVAILABLE AND NEARLY A NORTH-SOUTH AXIS OF FORCING...TRAINING OF HEAVIER RAINFALL WITH THUNDERSTORMS IS EXPECTED ACROSS AREAS EAST OF A GAINESVILLE...FORT WORTH...MERIDIAN...LAMPASAS LINE. A FLASH FLOOD WATCH HAS BEEN ISSUED FROM MONDAY THROUGH MIDNIGHT WEDNESDAY. IF THIS SYSTEM SLOWS UP EVEN MORE THAN CURRENTLY FORECAST...THE WATCH AREA MAY NEED TO BE EXTENDED BOTH WESTWARD AND IN TIME INTO WEDNESDAY FOR THE FAR EASTERN COUNTIES. THESE TRENDS WILL BE MONITORED IN FUTURE FORECASTS. RIVER FLOODING ALONG THE BRAZOS...TRINITY AND SULPHUR RIVER BASINS WILL LIKELY OCCUR AS WELL BY EARLY TUESDAY. AS THE UPPER LOW CREEPS SLOWLY ACROSS WEST TX TUESDAY NIGHT...THE SOLUTIONS BECOME MORE DIVERGED AND CONFIDENCE WANES QUICKLY ON RAINFALL CHANCES GOING INTO WEDNESDAY. FOR NOW FOLLOWED A COMPROMISE WITH SOME LINGERING SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE RED RIVER VALLEY AND FAR EASTERN COUNTIES. COOL VERTICAL PROFILES WITHIN THE UPPER LOW AND A PASSAGE OF A WEAK COLD FRONT SHOULD MAKE FOR RELATIVELY COOL TEMPERATURES ON WEDNESDAY WITH HIGHS IN THE UPPER 50S AND 60S. CONDITIONS WILL DRY OUT WEDNESDAY NIGHT AND THE REMAINDER OF THE WEEK AS THE UPPER LOW MOVES SLOWLY NORTHWARD AWAY. HIGHS BACK INTO THE UPPER 70S AND LOWER 80S WILL LIKELY RETURN BY SATURDAY WITH AN UPPER RIDGE OVER THE AREA WITH NO RAINFALL EXPECTED. 05/ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 67 74 56 66 50 / 20 100 100 80 20 WACO, TX 65 76 55 66 51 / 20 100 100 70 10 PARIS, TX 65 74 60 65 52 / 20 100 100 100 30 DENTON, TX 65 74 54 65 47 / 30 100 90 80 10 MCKINNEY, TX 65 72 57 66 50 / 20 100 100 90 20 DALLAS, TX 67 75 56 66 52 / 20 100 100 80 20 TERRELL, TX 65 74 56 65 51 / 20 100 100 90 20 CORSICANA, TX 66 74 55 66 51 / 20 90 100 90 20 TEMPLE, TX 66 77 54 67 48 / 20 90 100 70 10 MINERAL WELLS, TX 64 78 52 68 44 / 50 90 80 70 10 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 7 AM CDT MONDAY THROUGH TUESDAY EVENING FOR TXZ092>095-103>107-118>123-133>135-144>148-156>162-174-175. && $$ /
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
339 AM CDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 339 AM CDT MON MAR 19 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES AND HOW WARM TO GO WITH TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING OVER THE WESTERN U.S. AND STRONG RIDGING FROM THE SOUTHEASTERN U.S. INTO THE WESTERN GREAT LAKES REGION. WITHIN THE SOUTH-SOUTHWEST FLOW AHEAD OF THE TROUGH...IT IS TOUGH TO FIND ANY SHORTWAVES OF NOTE ON WATER VAPOR. THIS IS PRIMARILY DUE TO PLENTIFUL PACIFIC MOISTURE AND BLOW-OFFS FROM EVENING CONVECTION OVER THE SOUTHERN PLAINS. RUC ANALYSIS SHOWS VERY FEW AS WELL. AHEAD OF THE DEEP TROUGH...A SOUTHWEST 40-60 KT 850MB JET EXISTS OVER THE PLAINS INTO THE FORECAST AREA...HELPING TO MAINTAIN A CONTINUOUS FEED OF MOISTURE TRANSPORT FROM THE GULF OF MEXICO. PRECIPITABLE WATER VALUES ON 00Z SOUNDINGS REFLECT THE MOISTURE TRANSPORT... RANGING FROM 1-1.3 INCHES FROM GRB TO OAX...DVN...TOP AND FWD. THESE ARE 250-310 PERCENT ABOVE NORMAL. DESPITE ALL OF THIS MOISTURE... THERE IS VERY LITTLE OCCURRING ON REGIONAL RADARS...AND AGAIN THIS MIGHT BE DUE TO LACK OF NOTABLE SHORTWAVE FEATURES. IN ADDITION...ALTHOUGH THE ENVIRONMENT HAS A LOT OF MOISTURE WITH RESPECT TO NORMAL...00Z SOUNDINGS FROM OAX...DVN AND MPX WERE ACTUALLY FAIRLY DRY OUTSIDE OF THE 800MB MOISTURE JUST BELOW THE CAP. NEAREST PRECIPITATION ON RADAR IS IN MISSOURI AND WESTERN KANSAS. THE BREEZY SOUTHERLY FLOW...AHEAD OF A 982MB LOW IN EASTERN MONTANA...HAS HELPED TO KEEP TEMPERATURES UP IN THE 60S AND DEWPOINTS IN THE MID TO UPPER 50S. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE UPPER LEVEL PATTERN THROUGH THE SHORT TERM...ALL SHOWING THE CURRENT WESTERN TROUGH MOVING INTO THE WESTERN PLAINS ON TUESDAY...THEN SPLITTING APART. THE MAIN TREND IS THAT THE SOUTHERN END WHICH CUTS OFF INTO AN UPPER LOW IS FARTHER SOUTH AND WEST FOR WEDNESDAY AND WEDNESDAY NIGHT. THIS RESULTS IN RIDGING BUILDING BACK WESTWARD INTO THE FORECAST AREA WEDNESDAY NIGHT. DESPITE THE GOOD AGREEMENT ON THE UPPER PATTERN...DETAILS ARE MURKY AT BEST...ESPECIALLY WHEN IT COMES TO PRECIPITATION. THE REASONS ARE TWO FOLD: 1. HAVING THE ABNORMALLY HIGH MOISTURE STREAM EXPECTED TO STAY PUT OVER THE FORECAST AREA THROUGH THE SHORT TERM PERIOD...AND 2. ANY WEAK SHORTWAVE FORCING COULD ACT ON THE MOISTURE STREAM AND CAUSE PRECIPITATION TO OCCUR. THE DAILY DISCUSSIONS BELOW REPRESENT THE BEST ATTEMPT TO FIGURE OUT THE DETAILS. TODAY AND TONIGHT...THERE ARE INDICATIONS BY THE 19.00Z NAM/GFS/REGIONAL CANADIAN OF A WEAK SHORTWAVE COMING OUT OF MISSOURI AND LIFTING NORTHEAST THROUGH THE FORECAST AREA TODAY. THE NAM AND GFS BOTH PRODUCE PRECIPITATION WITH THIS SHORTWAVE...LIKELY OCCURRING IN THE 15-21Z TIME PERIOD...WHEREAS THE REGIONAL CANADIAN ONLY PRODUCES PRECIPITATION NEAR GRANT COUNTY. THE 19.03-19.05Z HRRR RUNS HAVE LOOKED A LOT LIKE THE REGIONAL CANADIAN AS WELL...GIVING A LITTLE MORE CONFIDENCE TOWARDS A DRIER SOLUTION. GIVEN THE FACT THAT IT IS TOUGH TO FIND ANY NOTABLE SHORTWAVE IN WATER VAPOR AND THE DRIER 00Z SOUNDING LOOK...HAVE LOWERED PRECIPITATION CHANCES TODAY TO MOSTLY 20-40 PERCENT. DOES SEEM THAT THE AFTERNOON WOULD HAVE BETTER POTENTIAL GIVEN THAT MUCAPE VALUES COULD RANGE FROM 500-1500 J/G...SO THE 40 PERCENT EXIST THEN. STILL...IT IS HARD TO FIND A TRUE TRIGGER IN THE AFTERNOON WITH LITTLE IF ANY HEIGHT FALLS OR SHORTWAVE COMING ACROSS. NOTE THAT WHERE THE HIGHEST CAPE EXISTS...0-6/0-3KM SHEAR IS LESS THAN 25 KT...SUGGESTING STORM ORGANIZATION AND SEVERE WEATHER IS NOT ANTICIPATED. ANOTHER ROUND OF PRECIPITATION WHICH LOOKS MORE CERTAIN WILL MOVE INTO AREAS WEST OF THE MISSISSIPPI RIVER THIS EVENING. THIS PRECIPITATION IS ASSOCIATED WITH A DEEPER WARM CONVEYOR BELT SURGE COMING OUT OF THE SOUTHERN PLAINS. HOWEVER...A LOT OF UNCERTAINTY EXISTS IF THE PRECIPITATION WILL MOVE EAST OVERNIGHT AND HOW MUCH OF IT STAYS INTACT. THE REASON FOR THIS UNCERTAINTY IS THAT IT APPEARS THE WARM CONVEYOR MAY SPLIT APART AS IT PUSHES EAST INTO THE UPPER RIDGING...LIKE THE SPLIT OCCURRING WITH THE WESTERN UPPER TROUGH. THEREFORE FOR TONIGHT BEST CHANCES FOR PRECIPITATION...IN THE 60-70 RANGE...WILL STAY WEST OF THE MISSISSIPPI RIVER. TUESDAY THROUGH WEDNESDAY NIGHT...WITH THE TREND FOR THE UPPER LEVEL TROUGH TO SPLIT SOONER...THE OVERALL FORECAST FOR THIS TIME PERIOD LOOKS DRIER...ESPECIALLY FOR WISCONSIN. PRECIPITATION FORECASTS THAT WERE MOSTLY OVER THE AREA HAVE NOW SHIFTED WEST TO HANDLE THE FARTHER WEST UPPER TROUGH AND SURFACE COLD FRONT. AS SUCH...CHANCES HAVE BEEN REDUCED. REGARDING A FEW DETAILS...TUESDAY MORNING COULD BE QUIET AS DEPICTED BY THE REGIONAL CANADIAN AND GFS...RESULTING FROM THE WARM CONVEYOR BELT FALLING APART. THIS IS ONLY TEMPORARY BECAUSE IN THE AFTERNOON A NEW SURGE OF SHOWERS AND EMBEDDED THUNDER SHOULD COME UP THROUGH THE WEST HALF OF IOWA AND POSSIBLY ENTER SOUTHEAST MINNESOTA. VERY GOOD AGREEMENT EXISTS ON THIS...RESULTING FROM A SHORTWAVE EJECTING OUT OF THE UPPER TROUGH. FOR TUESDAY NIGHT...THIS SURGE OF PRECIPITATION AGAIN LOOKS TO STAY MORE TO OUR WEST AND NORTHWEST...AGREED TOO WITH THE NEW 19.00Z ECMWF. IT IS CONCEIVABLE NOW THAT WEDNESDAY ENDS UP DRY AS UPPER LEVEL AND FRONTOGENETICAL FORCING WANES...BUT FOR NOW HAVE MAINTAINED SOME LOW CHANCES PER CONTINUITY AND STILL SOME WEAK FORCING INDICATIONS. THAT FRONTOGENETIC FORCING MAY TRY TO STRENGTHEN BACK UP WEDNESDAY NIGHT IF THE UPPER LOW KICKS OUT AS PROGGED. THUS HIGHER CHANCES ARE INDICATED THEN. REGARDING TEMPERATURES THROUGHOUT THE SHORT TERM...GIVEN THE PERIODIC ROUNDS OF PRECIPITATION...HIGHS ARE DIFFICULT TO FORECAST. 850MB TEMPS HOLD BETWEEN 10-12C AND THE TRUE SURFACE COLD FRONT... WHICH LOOKS LIKE IT ENDS UP FALLING APART...DOES NOT MOVE INTO THE AREA UNTIL WEDNESDAY NIGHT. IF ANY SUN OCCURS...TEMPERATURES COULD EASILY JUMP WELL INTO THE 70S AND POSSIBLY LOW 80S. FOR NOW STAYED WITH A BLEND OF GUIDANCE WHICH DID CAUSE AN INCREASE IN HIGHS FOR TUESDAY AND WEDNESDAY...RESULTING TOO FROM THE UPPER TROUGH SLOWING DOWN. LOWS ARE LIKELY TO REMAIN IN THE 50S TO LOW 60S...WARMEST TONIGHT. SEE CLIMATE SECTION BELOW FOR POSSIBLE RECORDS. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 339 AM CDT MON MAR 19 2012 OVERALL MUCH BETTER AGREEMENT EXISTS TODAY AMONGST THE 19.00Z GUIDANCE WITH THE HANDLING OF THE UPPER LEVEL PATTERN...INCLUDING THE UPPER LOW. IF ANYTHING...THE ECMWF HAS TRENDED COMPLETELY TOWARDS PAST AND CURRENT GFS RUNS...WHICH SUGGESTS A CONTINUATION OF ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THIS ALSO MATCHES CFS FORECASTS WHICH SUGGESTS THE SAME FOR THE MARCH 24TH THROUGH 28TH PERIOD. MAIN FOCUS FOR MUCH OF THE LONG TERM PERIOD IS ON THE UPPER LOW OVER THE SOUTHERN PLAINS WEDNESDAY NIGHT. GOOD AGREEMENT EXISTS THAT IT WILL LIFT NORTHEAST INTO NORTHERN MISSOURI BY FRIDAY IN RESPONSE TO DIGGING TROUGHING OFF THE U.S. WEST COAST. A WARM CONVEYOR BELT OF PRECIPITATION LOOKS TO FORM AHEAD OF THIS LOW AND IMPACT THE AREA THURSDAY AND THURSDAY NIGHT...POSSIBLY FRIDAY AS WELL IF THE GFS IS CORRECT. SIMILAR TO THE SHORT TERM PERIOD...PRECIPITABLE WATER VALUES ARE WELL ABOVE NORMAL...300 TO 350 PERCENT OR SO. RAISED PRECIPITATION CHANCES TO 40-50 AND FURTHER INCREASES MAY BE NECESSARY. SOME SHOWERS COULD STILL PERSIST FOR FRIDAY NIGHT AND SATURDAY AS THE UPPER LOW SCOOTS OFF TO THE EAST...AND WHILE THERE IS A RELATIVE COOL POOL OF AIR ALOFT. ANTICIPATING DRY CONDITIONS FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UPPER RIDGING BUILDING OVER THE PLAINS IN THE WAKE OF THE UPPER LOW...AS WELL AS SURFACE RIDGING BUILDING IN AT THE SURFACE. BACK TO TEMPERATURES...DESPITE THE APPROACH OF THE UPPER LOW FOR THURSDAY AND FRIDAY AND ITS ASSOCIATED PRECIPITATION...BOTH MEX AND 19.00Z ECMWF 2 METER GRID GUIDANCE HAVE REALLY WARMED UP THIS TIME PERIOD. IN FACT...THE ECMWF SUGGESTS POTENTIAL FOR RECORD HIGHS ON THURSDAY. GIVEN THE FACT THAT THE ECMWF DOES CONSIDER PRECIPITATION IMPACTS ON TEMPERATURES...HAVE RAISED TEMPERATURES SOME OVER THE BLEND OF GUIDANCE. FURTHER INCREASES MAY BE NECESSARY. SHOULD SEE SOMEWHAT OF A COOL DOWN FOR THE WEEKEND...BUT 850MB TEMPS ONLY DROP TO 4-6C AT MOST. THIS WILL KEEP READINGS ABOVE NORMAL. && .AVIATION... 1100 PM CDT SUN MAR 18 2012 LOOK FOR MVFR CIGS TO DEVELOP IN REGION OF HIGH LOW LEVEL SATURATION AGAIN TONIGHT...ACROSS WESTERN PORTIONS OF MN/IA. IT SHOULD STAY JUST WEST OF KRST...LIKE IT DID THIS MORNING AND THE PREVIOUS MORNING. STILL...CLOUDS WILL BE ON THE INCREASE...WITH LOWERING CIGS...TOWARD 12Z AS AN UPPER LEVEL SHORTWAVE TROUGH MOVES NORTHEAST OUT OF THE PLAINS. THE SHORTWAVE WILL LIKELY BRING SOME -SHRA WITH IT ALSO...WITH THE BETTER CHANCES LOOKING TO BE BETWEEN 15-21Z. MLCAPES NEAR 1000 J/KG...BUT ITS PRETTY SKINNY CAPE...NOT FAVORABLE FOR STRONGER STORMS. SOME LIGHTNING COULD BE POSSIBLE. WILL STICK WITH CB MENTION TO COVER THIS RISK FOR NOW. AS THE SHORTWAVE EXITS LATER MONDAY AFTERNOON...COULD SEE SOME IMPROVEMENT IN CIGS...ALTHOUGH ANOTHER LOWERING COULD OCCUR WITH ANOTHER SHORTWAVE SLATED TO MOVE NORTH ACROSS MN MONDAY EVENING. THE SKY FORECAST WILL REMAIN DIFFICULT WITH THE UNSEASONABLY MOIST AIRMASS PERSISTING. MORE -SHRA/TS WILL BE POSSIBLE OVERNIGHT MONDAY...WITH CHANCES THEN FOR THE REST OF THE WEEK. CHALLENGING FORECAST TRYING TO HIGHLIGHT THE PERIODS WHEN PCPN WILL BE MORE LIKELY...AS THE MOIST AIR MASS WILL ALLOW NEARLY ANY FOCUSING MECHANISM TO PRODUCE SOME -SHRA. WINDS WILL STAY HIGH WITH AFTERNOON MIXING LEADING TO 30 TO 35 KT GUSTS AT KRST...A BIT LESS AT KLSE. && .CLIMATE...THIS WEEK 339 AM CDT MON MAR 18 2012 TEMPERATURES LOOK TO GRADUALLY COOL THIS WEEK WITH PERIODS OF PRECIPITATION EXPECTED EACH DAY. HOWEVER...THIS PROCESS IS GOING TO BE VERY SLOW AS THE UNSEASONABLY WARM AIRMASS NEVER GETS FULLY SHUNTED EAST OF HERE UNTIL MAYBE THIS WEEKEND ACCORDING TO LATEST MODEL GUIDANCE. THEREFORE...POTENTIAL EXISTS EACH DAY FOR RECORD HIGHS AND MORE LIKELY RECORD HIGH MINIMUMS. CURRENT FORECAST PLAYS TEMPERATURES A LITTLE CONSERVATIVELY. IF MORE SUN OCCURS THAN FORECAST FOR TODAY...TUESDAY OR WEDNESDAY...RECORDS HIGHS ARE MORE LIKELY TO BE BROKEN. WEDNESDAY MAY BE THE TOUGHEST DAY TO BREAK RECORD HIGHS WITH MOST LOCATIONS HAVING RECORDS BETWEEN 75 TO 80...EXCEPT ROCHESTER AND MEDFORD WHICH ARE AT 70. FOR A LIST OF WHAT HAS OCCURRED REGARDING RECORDS THUS FAR AS WELL AS THOSE THAT COULD FALL IN THE DAYS TO COME...PLEASE SEE THE TOP NEWS STORY ON OUR WEBSITE ON THE UNSEASONABLY WARM MARCH. && .ARX WATCHES/WARNINGS/ADVISORIES... 339 AM CDT MON MAR 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK CLIMATE......AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
328 AM CDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH TUESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AMPLIFIED UPPER PATTERN ACROSS THE CONTINENT EARLY THIS MORNING...WITH A LARGE UPPER TROUGH OVER THE INTER-MOUNTAIN WEST AND SUBTROPICAL RIDGING CENTERED OVER THE CENTRAL GREAT LAKES. A LARGE PLUME OF MOISTURE IS HEADING NORTHEAST OVER THE GREAT PLAINS THOUGH PRECIP ECHOES ARE WIDELY SCATTERED OVER MISSOURI AND KANSAS. ONE SHORTWAVE OF NOTE IS EMBEDDED IN THE SW TROPICAL FLOW OVER KANSAS...BUT IS FAIRLY INACTIVE AT THE MOMENT. PLENTY OF CAPPING IN PLACE AS DEPICTED ON 00Z RAOBS OVER THE REGION. CLOSER TO HOME...AREA OF 6-7KFT CU HAS BEEN EXPANDING OVER FAR NE WISCONSIN AND THE EASTERN UPPER PENINSULA. AS MOISTURE STREAMS INTO THE REGION FROM THE CENTRAL PLAINS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN OVER THE NEXT 36 HOURS. TODAY...LARGE TROUGH OVER THE WEST WILL SLOWLY SLIDE ACROSS THE ROCKIES WHILE MID-LEVEL RIDGING WILL BUILD OVER THE CENTRAL GREAT LAKES. SLUG OF TROPICAL MOISTURE FROM THE SOUTHERN PLAINS WILL LIFT NORTH INTO WISCONSIN LATE IN THE MORNING AND THROUGH THE AFTERNOON...WITH PWATS CLIMBING TO GREATER THAN 1.25 INCHES...WHICH IS NEAR THE HIGHEST ON RECORD FOR THE MONTH OF MARCH. AS THE COLUMN MOISTENS...MODELS PROJECT THE STRONG CAP IN PLACE ACROSS THE REGION PARTIALLY ERODES...THOUGH THE NAM COMPLETELY WIPES IT OUT. BASED ON UPSTREAM SOUNDINGS...DO NOT THINK THIS IS REASONABLE. INSTEAD...WILL GO MORE WITH THE GFS IDEA OF KEEPING A WEAKENED CAP AROUND. BUT EVEN WITH A WEAKENED CAP...MODIFIED PROGGED SOUNDINGS OVER CENTRAL WISCONSIN USING A 74/58 PARCEL YIELDS ABOUT 900 J/KG OF ML CAPE AND NO CIN. WILL HAVE TO GET TO THE MIDDLE 70S TO REACH THE CONVECTIVE TEMPERATURE TO GET PAST THE CAP THIS AFTERNOON. LACK OF UPSTREAM ECHOES AND TRIGGERS LEADS ME TO GO DRY ACROSS MOST OF THE AREA THROUGH THE MORNING. IMPULSE OVER KANSAS SHOULD APPROACH THE REGION IN THE AFTERNOON WHICH COULD INTERACT WITH DAYTIME INSTABILITY TO CREATE SCT SHOWERS AND TSTORMS. STILL NOT THINKING ANYTHING SEVERE TODAY...BUT SOME OF THE STRONGEST STORMS COULD PRODUCE SMALL HAIL AND BRIEF GUSTY WINDS. WILL HAVE MORE CLOUD COVER AND MOISTURE AROUND THAN YESTERDAY...THOUGH LOOK TO BE OFF TO A WARMER START THAN YESTERDAY TOO. WILL GO WITH TEMPS A DEGREE OR TWO COOLER. TONIGHT...THE AIRMASS CHANGES VERY LITTLE AS THE DEEP TROUGH OVER THE WESTERN HARDLY MOVES TO THE EAST. AS MOIST AS THE COLUMN APPEARS...WOULD NOT TAKE MUCH OF A FEATURE OR SHORTWAVE IMPULSE TO TRIGGER SHOWERS AND ISOLD TSTORMS. WILL KEEP A MENTION OVER THE WESTERN 2/3RDS OF THE FORECAST AREA. SHOULD SEE A WARMER AND MORE MUGGY NIGHT...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S AWAY FROM LAKE MICHIGAN. TUESDAY...SOUTHERN PIECE OF THE WESTERN TROUGH CUTS OFF OVER WESTERN TEXAS WHILE SURFACE LOW PRESSURE TRAVELS NORTH OVER THE CENTRAL PLAINS. COLD FRONT ATTACHED TO THE LOW WILL SUBTLY SHIFT EAST TO THE MN/WI BORDER BY LATE IN THE AFTERNOON. AIRMASS CHANGES VERY LITTLE...BUT PROGGED SOUNDINGS SHOW SOME DRYING IN THE MID-LEVELS THAT LEADS TO SLIGHTLY LESS INSTABILITY THAN PROGGED FOR TODAY. THAT WONT LEAD TO A BIG CHANGE (IF ANY) IN THE FORECAST THOUGH AND WILL KEEP POPS ACROSS THE WESTERN 2/3RDS OF THE FORECAST AREA. HIGHS PERHAPS A FEW DEGREES COOLER OVER NORTH-CENTRAL WISCONSIN DUE TO CLOUD COVER AND POTENTIAL PRECIP...THOUGH LITTLE CHANGE IN TEMPS FARTHER EAST. .LONG TERM...TUESDAY NIGHT THRU SUNDAY. MAIN FORECAST CONCERNS ARE TEMPS AND PRECIP CHANCES. HIGHLY AMPLIFIED PATTERN WHICH HAS DOMINATED FOR THE PAST SEVERAL DAYS WITH A DEEP TROUGH OVER THE WESTERN U.S. AND RIDGING OVER THE EASTERN U.S. WILL SLOWLY TRANSITION TO MORE OF A SPLIT FLOW AS CUT OFF UPPER LOW SITS AND SPINS IN THE SOUTHERN PLAINS AND MORE OF A ZONAL FLOW DEVELOPS ACROSS THE NORTHERN U.S. AND SOUTHERN CANADA. MODEL TRENDS HAVE BEEN TO STALL THE UPPER LOW WELL TO OUR SW...KEEPING WARMER TEMPS ACROSS THE AREA LONGER...AND HOLDING OFF BEST PRECIP CHANCES UNTIL LATER THIS WEEK. PINNING DOWN BEST CHANCES FOR PRECIP WILL BE VERY CHALLENGING AS MODELS HAVE NOT REMAINED CONSISTENT ENOUGH TO HAVE CONFIDENCE IN ANY ONE SOLUTION. DUE TO THE MUCH SLOWER EASTWARD PROGRESSION OF THE UPPER LOW AS ADVERTISED BY THE LAST COUPLE OF MODEL RUNS... HAVE MADE SOME SIGNIFICANT CHANGES TO THE POPS AND CLOUDS GRIDS FOR MID-WEEK. FIRST CHANCE OF PRECIP WILL COME TUESDAY NIGHT AND WEDNESDAY AS FRONT CROSSES INTO THE STATE. STILL SOME UNCERTAINTY WITH HOW FAR SOUTH THE FRONT WILL GET. DECIDED TO PULL POPS FOR ALL BUT FAR NORTH-CENTRAL WI TUESDAY NIGHT...AND CHOPPED WEDNESDAY POPS TO CHANCE ACROSS CENTRAL AND NORTH-CENTRAL WI AND SLIGHTS OVER THE EAST...FAVORING A SLOWER SOLUTION...PLUS THE BEST FORCING WILL REMAIN CLOSER TO A UPPER JET NORTH OF THE REGION. REDUCED CLOUDS MAINLY ACROSS EASTERN WI AS WELL. MODELS HAVE HELD MOST OF THE ACTIVITY WITH THIS SYSTEM NW OF THE CWA...SO WOULD NOT BE SURPRISED IF WE MISS OUT ON THIS SYSTEM COMPLETELY IN THE SE...AND WILL ONLY KEPT THE SLIGHT CHANCE POPS TO COVER ANY ISOLATED ACTIVITY OUT AHEAD OF THE FRONT IN THE PERSISTENT MOIST SOUTH FLOW. HAVE INCREASED POPS FOR LATE IN THE WEEK AS MODELS NOW SHOW THE UPPER LOW WORKING INTO THE SOUTHERN GREAT LAKES...BUT CONFIDENCE REMAINS LOW AS HOW QUICKLY THE UPPER LOW WILL TOWARD THE AREA. WILL CONFINE THUNDER MENTION FOR THE DAYTIME HOURS... MAINLY THE AFTERNOON...ALTHOUGH CONVECTIVE PARAMETERS NOT VERY IMPRESSIVE WITH CLOUD COVER REDUCING INSTABILITY AND LAPSE RATES NOT TOO STEEP. THE RECORD BREAKING...OR NEAR RECORD BREAKING...WARMTH LOOKS TO CONTINUE INTO WEDNESDAY NOW...WITH 850/925MB TEMPS STILL SUPPORTIVE OF HIGHS IN THE MIDDLE TO UPPER 70S ACROSS EAST-CENTRAL WI. SLIGHTLY COOLER TEMPS ALOFT AND MORE CLOUDS EXPECTED AS YOU WORK TOWARD NW AND NORTH-CENTRAL WI...AS THE FRONT SAGS ACROSS THE STATE...SO EXPECT COOLER TEMPS THERE. THICKER CLOUD COVER AND/OR THE FRONT SAGGING FARTHER SOUTH COULD KEEPS TEMPS COOLER ACROSS THE AREA...HOWEVER FAVOR THE WARMER TEMPS. ABOVE NORMAL TEMPS ARE EXPECTED THROUGH THE UPCOMING WEEKEND...WITH NO COLD AIR IN SIGHT FOR THE AREA. EVEN AS UPPER LOW COMES CLOSER...IT SEEMS TO LOSE ITS SOMEWHAT CHILLY CORE...SO WILL BUMP UP TEMPS A LITTLE LATE IN THE WEEK. && .AVIATION...VFR CONDITIONS TO PREVAIL TONIGHT INTO MONDAY. LATER MONDAY A VFR CIG WILL DEVELOP AS SCATTERED SHOWERS WORK INTO THE STATE. TDH && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/BERSCH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
648 AM EDT MON MAR 19 2012 .AVIATION... 12Z TAFS...MAIN AVIATION CONCERN WILL CONTINUE TO BE CONVECTIVE POTENTIAL TODAY. MOST OF THE FOG HAS BEEN CONFINED TO EXTREME NORTHWEST OHIO THIS MORNING WHERE WEAK LOW LEVEL EASTERLY COMPONENT HAS PROVIDED SOME MARINE INFLUENCE FROM LAKE ERIE. STILL SEE A LOW END POTENTIAL OF SOME PATCHY FOG AFFECTING KFWA OVER NEXT FEW HOURS BUT MAY BE ABLE TO PULL THIS MENTION WITH THE 12Z TAFS AS SOME INCREASING MID/HIGH CLOUDS SHOULD LIMIT THIS POTENTIAL. OTHERWISE...SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS NORTHWEST ILLINOIS...BUT SHORT WAVE RESPONSIBLE FOR THIS CONVECTION SHOULD TAKE A TRACK TO KEEP THIS THREAT WEST OF TERMINALS THIS MORNING. HOWEVER...ANOTHER UPSTREAM SHORT WAVE ACROSS NORTHERN ARKANSAS/SOUTHERN MISSOURI SHOULD LIFT INTO NORTHEAST ILLINOIS/NORTHWEST INDIANA THIS AFTERNOON. STEEPENING MID LEVEL LAPSE RATES AND WEAK TO MODERATE INSTABILITY SHOULD BE ENOUGH TO GENERATE AT LEAST ISOLATED THUNDERSTORMS ACROSS NORTHWEST/NORTH CENTRAL INDIANA THIS AFTERNOONN. GREATER COVERAGE MAY REMAIN WEST OF KSBN AND AT THIS FORECAST DISTANCE WILL LIKELY CONFINE MENTION TO CB CLOUD GROUP AT KSBN THIS AFTERNOON. ISOLATED AFTERNOON THUNDERSTORMS ALSO POSSIBLE AT KFWA BUT WEAKER MID LEVEL FORCING MAKES THIS SCNEARIO MORE QUESTIONABLE. THREAT OF PRECIP SHOULD END BY EARLY EVENING AS MID LEVEL HEIGHTS BUILD ACROSS THE GREAT LAKES. SOUTH WINDS TO CONTINUE THROUGH THE PERIOD...WITH SOME GUSTS TO AROUND 18 TO 20 KNOTS EXPECTED AT KSBN THIS AFTERNOON WITH A SLIGHTLY STRONGER SFC PRESSRUE GRADIENT IN PLACE. && .PREV DISCUSSION... /ISSUED 435 AM EDT MON MAR 19 2012/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT MUCH OF THE SAME FOR BEGINNING OF THE WEEK...WITH FORECAST ATTENTION CENTERED ON RECORD BREAKING WARMTH AND CONVECTIVE POTENTIAL. IN THE VERY NEAR TERM...HAVE ISSUED A DENSE FOG ADVISORY FOR NORTHERN NORTHWEST OHIO COUNTIES AND HILLSDALE COUNTY MICHIGAN. STRONGER RADIATIONAL COOLING ACROSS THESE LOCATIONS EARLIER...COMBINED WITH WEAK EAST SOUTHEAST LOW LEVEL FLOW COMPONENT HAS BEEN CONDUCIVE FOR SOME WESTWARD EXPANSION OF DENSE FOG THAT FORMED WEST OF LAKE ERIE. THIS DENSE FOG MAY NOT MAKE IT AS FAR WEST AS THE FAR WESTERN PORTIONS OF THE COUNTIES IN THE DENSE FOG ADVISORY BUT FOG SATELLITE PRODUCT AND OBSERVATIONS SUGGEST A SLOW WESTWARD EXPANSION OF DENSE FOG OVERNIGHT. THE SLOW MOVING CONVECTIVELY ENHANCED VORT MAX THAT BROUGHT YESTERDAYS PRECIPITATION HAS EXITED INTO EASTERN OHIO THIS MORNING. SOME ISOLATED SHOWERS TRYING TO DEVELOP IN NARROW AXIS OF ENHANCED LOW/MID LEVEL WARM ADVECTION BEHIND THIS DEPARTING VORT MAX FROM SOUTH CENTRAL LOWER MICHIGAN INTO NORTHWEST OHIO. RUC INITIALIZATION SOUNDINGS SUGGEST THESE SHOWERS ARE ELEVATED TO AN EXTENT MAKING IT DIFFICULT TO REALIZE MUCH ELEVATED INSTABILITY. SIMILAR CONCERNS IN TERMS OF MAGNITUDE OF ELEVATED INSTABILITY PERSIST ACROSS WESTERN PORTIONS OF THE AREA...ALTHOUGH SHORT TERM PROGS FROM NAM/RUC SUGGEST WEAK AREA OF SECONDARY LOW LEVEL MOISTURE/THETAE ADVECTION SHIFTING INTO NORTHWEST INDIANA THIS MORNING THAT MAY HELP TO ENHANCE ELEVATED INSTABILITY. A WEAK SHEARED VORT MAX ALSO LIFTING NORTHEASTWARD DOWNSTREAM OF LARGE SCALE WESTERN CONUS TROUGH MAY ALSO PROVIDE SOME WEAK MID/UPPER LEVEL SUPPORT TO GENERATE SOME ISOLD ELEVATED STORMS OVER THE NEXT FEW HOURS. A BETTER CHANCE OF THUNDERSTORMS EXISTS THIS AFTERNOON AND HAVE MADE NO CHANGES TO TSRA CHANCE POPS WEST/SLIGHT CHANCE EAST AS CONTINUED WEAK EMBEDDED WAVES LIFT INTO THE AREA. THE MOST NOTABLE OF THESE SHORT WAVES APPEARS TO BE SITUATED FROM EASTERN MISSOURI INTO NORTHERN ARKANSAS EARLY THIS MORNING. MID LEVEL LAPSE RATES ARE EXPECTED TO STEEPEN TOWARD MIDDAY AS AN ELEVATED MIXED LAYER ADVECTS NORTHEAST INTO THE AREA. SFC TEMPERATURES WARMING TO AROUND 80 THIS AFTERNOON SHOULD COMBINE WITH THESE STEEPER MID LEVEL LAPSE RATES FOR SBCAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. PRESENCE OF MID LEVEL RIDGE/LOW SHEAR WILL KEEP SEVERE THREAT LOW...WITH PERHAPS SLIGHTLY MORE RESPECTABLE 0 TO 6 KM BULK SHEAR VALUES INTO THE 20 TO 25 KNOT RANGE ACROSS WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. WILL MENTION JUST AN ISOLD HAIL/WIND THREAT IN THIS MORNINGS HWO. IN TERMS OF TEMPERATURES...MIXING TO AROUND 900 HPA SHOULD SUPPORT HIGHS FROM THE UPPER 70S TO AROUND 80 WHICH WOULD ONCE AGAIN BREAK THE RECORD HIGHS FOR THE DATE...76 AT FORT WAYNE AND 77 AT SOUTH BEND...BOTH SET IN 1921. UPPER LEVEL TROUGH DIGGING/AMPLIFICATION ACROSS THE ROCKIES WILL RESULT IN DOWNSTREAM MID LEVEL HEIGHT RISES ACROSS THE GREAT LAKES REGION TONIGHT/TUESDAY. MODEL GUIDANCE IS ALSO IN REASONABLE AGREEMENT IN A DRIER POCKET OF LOW LEVEL AIR ADVECTING NORTHWARD LATER TONIGHT AS THIS RIDGE AMPLIFIES...EFFECTIVELY SUPPRESSING ELEVATED CONVECTION. THUS...WILL KEEP FORECAST DRY TONIGHT. TUESDAY SHAPING UP TO BE ANOTHER DAY OF RECORD BREAKING WARMTH WITH DEEPER MIXING THAN MONDAY...THAT SHOULD SUPPORT HIGHS IN THE LOWER 80S MOST LOCATIONS. THIS DEEPER MIXING AND SLIGHTLY DRIER LOW LEVEL AIR SHOULD LIMIT DIURNAL INSTABILITY...AND WITH LARGE SCALE RIDGE IN PLACE...WILL KEEP REMAINDER OF SHORT TERM DRY. && LONG TERM... / WEDNESDAY THROUGH SUNDAY / TREND IN MODEL GUIDANCE HAS BEEN TO SLOW THE EASTERN PROGRESSION OF A SOUTHERN PLAINS CUT-OFF UPPER LOW LATE THIS WEEK INTO SATURDAY. THIS IS NOT SURPRISING GIVEN THE NATURE OF CUT-OFFS AND EXPECTED AMPLIFICATION OF A HIGHLY ANOMALOUS EASTERN CONUS UPPER RIDGE. AS A RESULT OPTED TO BUY INTO THIS SLOWER SOLUTION WITH THIS DEEP TROPOSPHERIC CIRCULATION NOW PROGGED TO DRIFT TO THE MID MS VALLEY BY FRIDAY...AND THE OH VALLEY BY SATURDAY. RAISED HIGHS SEVERAL DEGREES...ESPECIALLY THURSDAY AND FRIDAY GIVEN THE SLOWER SOLUTION. A COOL DOWN IN STILL IN THE WORKS FRIDAY INTO THIS WEEKEND PER HEIGHT FALLS AND INCREASING CLOUDS/RAIN?...STILL LIKELY REMAINING AROUND 10 DEGREES OR SO ABOVE NORMAL BY THIS WEEKEND (COMPARED TO EXPECTED RECORD HIGH TEMPS AROUND 30 DEGREES ABOVE NORMAL TO START THE PERIOD). SYSTEM WILL MATURE AND FILL A BIT WITH EWD DRIFT AS IT COLLIDES WITH THE RIDGE...GETTING ITS KICK FROM ANOTHER LONGWAVE TROUGH PROGGED TO DIG TOWARDS THE WEST COAST. GIVEN THIS EXPECT FORCING TO WEAKEN A BIT AS IT FINALLY MAKES ITS WAY INTO THE OH VALLEY AND SRN GREAT LAKES. HOWEVER...THERE STILL SHOULD BE A MORE ORGANIZED BAND OF SHOWERS TO ACCOMPANY THE WEAKENING LOW LEVEL BAROCLINIC ZONE/OCCLUDED FRONT...WITH A MODEL CONSENSUS FAVORING THE FRIDAY-FRIDAY NIGHT PERIOD FOR MEASURABLE RAINFALL LOCALLY. RAINFALL AMOUNTS ARE NOT LOOKING OVERLY IMPRESSIVE ALTHOUGH SOME LOCALIZED HEAVIER RAIN APPEARS POSSIBLE GIVEN SUFFICIENT MOISTURE/WEAK INSTABILITY. CHANCES FOR SHOWERS LINGER INTO SATURDAY AS THE UPPER LOW AND ASSOCIATED COLD POOL ALOFT SHIFTS INTO REGION. OVERALL... CHANGES TO POPS/WX WERE TO REMOVE LOWER CHC POPS WEDNESDAY NIGHT AND LOWER THURSDAY POPS TO SLIGHT CHC. ONLY MINOR TWEAKS OTHERWISE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MIZ081. OH...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR OHZ001-002- 004-005. LM...NONE. && $$ SHORT TERM...MARSILI LONG TERM...STEINWEDEL AVIATION...MARSILI
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
915 AM MDT MON MAR 19 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY... WINTER HAS DECIDED TO GO OUT LIKE A LION...AT LEAST OVER THE WESTERN COUNTIES TODAY. THE MONTANA DOT ROAD REPORT HAS SEVERE DRIVING CONDITIONS IN PETROLEUM COUNTY...WESTERN GARFIELD AND SOUTHWEST PHILLIPS COUNTIES DUE TO ICE AND SNOW...WHICH STARTED AROUND 4 AM THIS MORNING. JUST TO THE WEST OF THOSE COUNTIES CONDITIONS INCLUDE HEAVY SNOW WITH VISIBILITIES LESS THAN A QUARTER MILES WITH 30KT WINDS. BASED ON OBSERVATIONS...TWEAKED TEMPERATURES SLIGHTLY COOLER IN SOME WESTERN AREAS. EASTERN AREAS WILL CONTINUE WARMER THAN NORMAL. THE MAIN CHANGE WAS TO ADD AREAS OF FOG OVER MUCH OF THE AREA...AGAIN BASED ON CURRENT OBSERVATIONS. THIS MORNING THE SURFACE LOW CENTER COULD BE A BULLS-EYE FOR THE CWA. THAT MEANS THE STRONGEST WINDS ARE IN THE SOUTHWEST ZONES WHERE BLIZZARDS WARNINGS ARE IN EFFECT. THE REST OF THE HAZARDS APPEAR TO BE IN GOOD SHAPE SO NO PLANNED CHANGES THERE. SCT STRONG LATE WINTER STORM IS UNDERWAY ACROSS CENTRAL AND EASTERN MONTANA. NATIONAL ATTENTION GIVEN BY SPC MESOSCALE DISCUSSION AND SATELLITE PRECIPITATION ESTIMATES. SHORT TERM MODEL QPF DEPICTIONS HAVE CONVERGED ON A VERY WET AND HEAVY PRECIPITATION EVENT FOR TODAY. SIGNIFICANT GRADIENT OF MANY WEATHER ELEMENTS WILL OCCUR ACROSS THE CWA TODAY. NEAR NOTHING IN OUR EASTERN ZONES...TO A FULL OUT BLIZZARD IN OUR WESTERN ZONES. TIGHT SURFACE LOW PRESSURE OVER SOUTHEASTERN MONTANA WILL PUSH NORTH AND EAST...ALLOWING STRONG WINDS TO WRAP AROUND THE WESTERN SIDE OF THE LOW. WINDS HAVE ALREADY INCREASED EARLY THIS MORNING MORE THAN ANTICIPATED. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE LIKELY TODAY. MODERATE TO HEAVY SNOW ALONG WITH NORTHWESTERLY WINDS OF 30 TO 40 MPH WILL EASILY RESULT IN BLIZZARD CONDITIONS FOR SOUTHWEST PHILLIPS COUNTY AND PETROLEUM COUNTY. FELT IT WAS BEST TO UPGRADE TO A BLIZZARD WARNING FOR THOSE ZONES AND GIVE BUFFER ZONES OF WINTER STORM WARNING AND WINTER WEATHER ADVISORY FURTHER EAST THROUGH OUR CENTRAL CWA. RECENT HRRR MODEL RUNS HAVE BEEN SLIDING THE PRECIPITATION PROGRESSIVELY FURTHER EAST THAN PREVIOUS MODEL RUNS. GREATEST PRECIPITATION IMPACT WILL BE WITH HEAVY SNOW BETWEEN 12Z AND 18Z. GREATEST WIND IMPACT WILL BE NORTHWESTERLY WINDS IN THE 30G40KT RANGE THROUGHOUT THE DAY. STORM WILL DIMINISH QUICKLY TONIGHT AND DISAPPEAR ENTIRELY AFTER MIDNIGHT AS THE LOW PRESSURE SYSTEM EXITS NORTHEASTWARD INTO CANADA...TAKING THE MAIN FORCING AND MOISTURE WITH IT. TUESDAY THROUGH WEDNESDAY...UPPER LEVEL FLOW BECOMES MORE ZONAL WITH A SLIGHT SOUTHWESTERLY COMPONENT TO IT. ENOUGH OF A HIGH PRESSURE INFLUENCE FROM THE SOUTH WILL KEEP PRECIPITATION AWAY AS TEMPERATURES BEGIN TO SLOWLY REBOUND TO ABOVE NORMAL LEVELS AGAIN INTO MID WEEK. BMICKELSON .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SOUTHWEST FLOW ALOFT WILL PREVAIL FOR THURSDAY AND FRIDAY WITH AN UPPER TROUGH TO THE WEST AND RIDGE TO THE EAST. NORTHEAST MONTANA WILL BE WARM AND DRY BEING CLOSER TO THE RIDGE THAN THE TROUGH. A SLOW MOVING COLD FRONT DROP SOUTH ACROSS THE FORECAST AREA SATURDAY AND SUNDAY. MODELS BEGIN TO DIFFER IN THEIR SOLUTIONS AT THIS POINT BUT THEY POINT TOWARDS SOME MOISTURE WITH THIS FRONT AND POSSIBLY A SHORTWAVE OR TWO IN THE SOUTHWEST FLOW ALOFT. WILL MENTION A SLIGHT CHANCE OF SHOWERS. GFS IS FASTER THAN THE ECMWF WITH BRINGING THE UPPER TROUGH INLAND EARLY NEXT WEEK. WILL MENTION A SLIGHT CHANCE OF RAIN OR SNOW SHOWERS ON MONDAY DEPENDING ON TEMPERATURES. FORRESTER && .AVIATION... KGGW BEING IN OR NEAR THE MAIN BAND OF RAIN/SNOW THIS MORNING WILL SEE A MIX OF IFR/MVFR CONDITIONS THIS MORNING WITH STRONG NORTH WINDS. KOLF WILL SEE A VARIATION OF IFR/MVFR AND VFR CONDITIONS THIS MORNING WITH THE DEEP LOW PRESSURE SYSTEM EXPECT TO PASS NEAR KGGW AND KOLF THIS MORNING...A LULL IN THE WINDS IS EXPECTED IN THE LATE MORNING BEFORE STRONG WEST WINDS 20-30 KNOTS DEVELOP ON THE BACK SIDE OF THE LOW THIS AFTERNOON. KGGW AND KOLF WILL SEE A MIX OF IFR AND MVFR CONDITIONS THIS AFTERNOON WITH RAIN CHANGING TO SNOW BEFORE THE PRECIP ENDS AROUND 00Z AND CONDITIONS IMPROVE TO VFR BY 02Z. KSDY AND KGDV WILL BY ON THE DRY EAST SIDE OF THE LOW THIS MORNING WITH VFR CONDITIONS. LIGHT AND VARIABLE WINDS EARLY WILL BECOME SOUTH 15 TO 20 KNOTS THIS MORNING AND GRADUALLY TURN SOUTHWEST THIS AFTERNOON AND WEST 20-30 KNOTS BY EVENING AS THE SURFACE LOW LIFTS NORTH. KSDY AND KGDV WILL REMAIN VFR FOR THE MOST PART THIS AFTERNOON BUT SOME LOW CLOUDS IN THE WRAP AROUND MOISTURE MAY GIVE THEM BRIEF PERIODS OF MVFR CONDITIONS. FORRESTER && .GLASGOW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR CENTRAL AND SOUTHERN VALLEY...NORTHERN VALLEY. BLIZZARD WARNING UNTIL MIDNIGHT MDT TONIGHT FOR PETROLEUM... SOUTHWEST PHILLIPS. WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR CENTRAL AND SOUTHEAST PHILLIPS...GARFIELD...NORTHERN PHILLIPS. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
616 AM CDT MON MAR 19 2012 .AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. SHOWERS WILL MOVE INTO THE TAF SIGHTS THIS MORNING...BY ABOUT 14Z AND KLNK/KOFK AND 15-17Z AT KOMA. MVFR CEILINGS WILL ALSO ACCOMPANY THE RAIN...ALONG WITH GUSTY SOUTHEAST WINDS AT 15 TO 25 KTS. CONFIDENT THAT THUNDER SHOULD OCCUR AT KLNK THIS MORNING BASED ON RADAR TRENDS FOR A COUPLE HOUR PERIOD. BEYOND THEN...BEST THUNDER POTENTIAL SEEMS TO BE THIS AFTERNOON AT KOMA. RAIN SHOULD END AT KOFK/KLNK BY 00Z AND KOMA BY 02Z. THERE WILL ALSO BE A WIND SHIFT VERY LATE IN THE PERIOD...PERHAPS BY 20/09Z AT KOFK AS A COLD FRONT BEGINS TO MOVE INTO THE REGION. && .PREV DISCUSSION... /ISSUED 323 AM CDT MON MAR 19 2012/ DISCUSSION... TIMING OF PERIODS OF SHOWERS AND THUNDERSTORMS WILL BE THE MAIN FORECAST CONCERN IN THE SHORT TERM AS UPPER WAVE CUTS OFF OVER SOUTHERN TEXAS AND LINGERS THERE THROUGH THE PERIOD. A SURFACE TROUGH WAS LOCATED ACROSS WESTERN NEBRASKA AT 07Z SEPARATING DRY AIR TO THE WEST FROM MOIST AIR TO THE EAST. ISOLATED SEVERE STORMS HAD DEVELOPED JUST EAST OF THE TROUGH EARLIER IN THE EVENING. MAIN AREA OF CONVECTION EARLY THIS MORNING WAS OVER THE TEXAS PANHANDLE INTO SOUTHWEST KANSAS. SHORT RANGE HRRR GRADUALLY LIFTS THE STORMS NORTHEAST THROUGH THE MORNING WITH CURRENT TIMING BRINGING INITIAL ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS INTO EASTERN NEBRASKA AROUND 15Z. WEAK MID LEVEL INSTABILITY INDICATED BY FORECAST SOUNDINGS THROUGH THE MORNING WITH BETTER FORCING AND DEEPER MOISTURE IN THE AFTERNOON FROM SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA. EASTERN PORTION OF THE CWA IS INCLUDED IN SLIGHT RISK FOR SEVERE TODAY WITH STRONG SHEAR BUT LIMITED CAPE INDICATED BY CURRENT FORECAST SOUNDINGS. THIS INITIAL WAVE THEN SHIFTS EAST INTO THE MISSISSIPPI VALLEY TONIGHT WITH POPS DECREASING ACROSS THE AREA. A SECONDARY SURFACE WAVE LIFTS NORTH FROM THE SOUTHERN PLAINS ON TUESDAY BRINGING ANOTHER CHANCE OF THUNDERSTORMS TO THE AREA... ESPECIALLY TUESDAY AFTERNOON AND TUESDAY EVENING. SURFACE FRONT ASSOCIATED WITH THIS WAVE BECOMES QUASI-STATIONARY OVER WESTERN IOWA DURING THIS TIME WITH SOME POTENTIAL FOR LOCALLY HEAVY RAIN FROM EXTREME SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA...ALTHOUGH CURRENT FORECAST TRENDS PLACE AXIS OF HEAVY RAIN JUST EAST OF THE AREA. POPS AGAIN DECREASE TUESDAY NIGHT OVER THE AREA AS SURFACE WAVE LIFTS NORTHEAST AND WEAKENS. CLOSED UPPER LOW OVER TEXAS BEGINS TO IMPACT THE AREA ON WEDNESDAY AND WEDNESDAY NIGHT AS THE SYSTEM LIFTS NORTH BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS INTO THE AREA. TEMPERATURES EXPECTED TO STAY ON THE MILD SIDE ALTHOUGH THE CLOUD COVER AND PRECIP WILL KEEP READINGS COOLER THAN SEEN THE PAST FEW DAYS. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1047 AM EDT MON MAR 19 2012 .SYNOPSIS... SOUTHERLY FLOW ON THE BACKSIDE OF HIGH PRESSURE WILL ALLOW AN UNSEASONABLY WARM AIRMASS TO PERSIST THROUGH MUCH OF THE WEEK. DISTURBANCES IN THE UPPER ATMOSPHERE INTERACTING WITH AN UNSTABLE AIRMASS WILL PRODUCE A CHANCE OF THUNDERSTORMS TODAY. AN UPPER LEVEL HIGH WILL MOVE IN LATE MONDAY WHICH WILL BRING AN END TO THE THUNDERSTORMS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HEAT AND INSTABILITY WILL AGAIN GROW ACROSS THE FORECAST AREA TODAY. NO SIGNIFICANT CHANGES WERE NEEDED FOR THE MAX TEMP FORECAST...WHICH CURRENTLY BRINGS HIGHS TO NEAR THEIR RECORD VALUES (CVG 81...CMH 77...DAY 78). STEEP MID LEVEL LAPSE RATES WILL ALLOW FOR INSTABILITY TO DEVELOP TODAY...WITH AROUND 1000 J/KG OF MLCAPE EXPECTED (MAYBE 1500 IN SPOTS). HOWEVER...THE CWA WILL BE NEAR THE CENTER OF A MID LEVEL RIDGE...AND WIND SHEAR TODAY IS AT THE LOW END OF THE SPECTRUM. AT THIS TIME...THE RECENT HRRR RUNS SEEM TO BE ON THEIR OWN IN TERMS OF DEVELOPING A SIGNIFICANT AMOUNT OF THUNDERSTORMS OVER THE CWA. WITH LITTLE IN THE WAY OF DISCERNIBLE FORCING...IT IS MORE LIKELY THAT SHOWER AND THUNDERSTORM DEVELOPMENT WILL BE MOSTLY DISORGANIZED AND DIURNALLY DRIVEN. THE INSTABILITY IS PROBABLY ENOUGH TO WARRANT A RISK OF A STRONG STORM...BUT THE LACK OF SHEAR AND FORCING SEEM TO PRECLUDE A MORE WIDESPREAD SEVERE THREAT. TAILORED THE POPS A BIT WITH THE SLIGHTLY HIGHER CHANCE SHIFTING NORTH THROUGH TIME...EXITING THE SOUTHERN CWA BY EVENING AND THE NORTHERN CWA BY EARLY IN THE OVERNIGHT PERIOD. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... UPPER RIDGE BECOMES MORE ESTABLISHED TONIGHT...FORCING THE CONVECTION E. THE RIDGE WILL THEN REMAIN IN PLACE FOR THE REST OF THE PERIOD...KEEPING ANY CONVECTION CAPPED. TEMPERATURES WILL STAY UNSEASONABLY WARM. HIGHS WILL BE AROUND 80 EACH DAY AND WILL BE CLOSE TO OR ABOVE RECORD HIGHS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGHLY AMPLIFIED MID/UPPER LEVEL FLOW PATTERN WITH A LARGE SPRAWLING RIDGE CONTINUING TO INFLUENCE OUR WEATHER AT THE BEGINNING OF THE LONG TERM PERIOD. PREFER SLOWER ECMWF SOLN GIVEN HIGH DEGREE OF AMPLIFICATION. THIS WILL CONTINUE TO PROVIDE UNSEASONABLY WARM TEMPS AND DRY WEATHER WEATHER THRU MID WEEK. HAVE MAINTAINED A DRY FCST FOR THURSDAY. EXPECT HIGHS TO RANGE FROM THE UPPER 70S NORTH TO 80 SOUTH ON BOTH WED AND THU. AGAIN RECORD HIGH TEMPERATURES WILL BE IN JEOPARDY. RECORD HIGHS FOR WED ARE 82 AT CVG, 78 AT DAY AND 77 AT CMH. THE RECORDS FOR THURSDAY ARE WARMER WITH...85 CVG, 84 AT DAY AND 82 AT CMH. NUMERICAL MODELS CONTINUE TO TREND SLOWER BUT ARE HAVING A DIFFICULT TIME WITH CONSISTENCY REGARDING EASTWARD PROGRESSION OF UPPER LOW OVER THE NATIONS MID SECTION. WILL INTRODUCE LOW POPS INTO THE SW EARLY FRIDAY AND THEN SPREAD CHC POPS NE ACRS THE FA DURG THE DAY. WL BUMP POPS UP TO HIGH CHC EARLY SATURDAY WITH THE APPROACH OF SFC FRONTAL BOUNDARY. UNDER CONTD INFLUENCE OF THE UPPER LOW...WL CONTINUE LOW POPS THRU SAT AND THEN DIMINISH TO SLIGHT CHC ON SUNDAY AS THE INFLUENCE OF THE UPPER LOW BEGINS TO SHIFT SE. HIGH TEMPS WILL COOL BUT REMAIN ABOVE NORMAL...WITH FCST HIGHS IN THE UPPER 60S/70S ON FRIDAY AND LOWER AND MID 60S SATURDAY AND THEN UPPER 50S/LOWER 60S. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... PATCHY FOG MAY BE LOCALLY DENSE BUT WILL LIKELY NOT HIT ANY OF THE TAF SITES WITH FOG LESS THAN A MILE...AND ONLY BE AN ISSUE FOR AN HOUR OR SO AFTER DAYBREAK THIS MORNING. MID LEVEL CLOUDS WILL ABOUND TODAY. WHERE THEY THIN THERE SHOULD BE ENOUGH HEATING AND MOISTURE TO SUPPORT SOME DAYTIME CU THAT POSSIBLY GOES BKN AT TIMES BUT SHOULD BE WELL INTO THE VFR CATEGORY. FELT THAT SINCE THE UPPER LEVEL S/W THAT WAS HELPING SPARK EARLIER CONVECTION HAS MOVED EAST...THAT SHOWERS OR ISOLD THUNDERSTORMS WOULD BE A RARITY THIS AFTERNOON. WHILE STILL POSSIBLE...I DO NOT SEE THE NEED FOR PUTTING IN THE CHANCE OF PRECIP TODAY UNTIL IT CAN BE AMENDED WITH A CERTAINTY OF OCCURRENCE. OUTLOOK...THUNDERSTORMS POSSIBLE ON FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HATZOS SHORT TERM...SITES LONG TERM...AR AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
704 AM CDT MON MAR 19 2012 .DISCUSSION...UPDATED FOR 12Z AVIATION. && .AVIATION...SHOWERS HAVE MAINLY MOVED OUT OF THE AREA AS OF 12Z...ALTHOUGH A FEW SHOWERS ARE STILL IN THE VICINITY OF VICTORIA. EXPECT CIGS TO IMPROVE THROUGH THE DAY...WITH LRD EXPECTED TO GO SCT OR FEW IN THE AFTERNOON. GUSTY WINDS CONTINUE THROUGH THE DAY WITH A LLJ CONTINUING OVER THE AREA. TONIGHT WITH A 40-50KT LLJ ACROSS THE AREA AND AN APPROACHING COLD FRONT WILL SEE SHOWERS AND THUNDERSTORMS DEVELOPED. HAVE INCLUDED TSRA IN ALL TAFS EXCEPT LRD WHERE CHANCES ARE A BIT LOWER. THESE SHOWERS AND STORMS HAVE THE POTENTIAL TO BRING VERY STRONG WIND GUSTS. THE COLD FRONT WILL APPROACH THE LAREDO AREA LATE IN THIS TAF PERIOD...AND MOVE ACROSS THE AREA THE REST OF TUESDAY MORNING. && .PREV DISCUSSION... /ISSUED 433 AM CDT MON MAR 19 2012/ SHORT TERM (TODAY AND TONIGHT)...ISOLATED SHOWERS AND A COUPLE OF THUNDERSTORMS ARE ONGOING AT THE BEGINNING OF THE PERIOD ASSOCIATED WITH A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE MOST CONCENTRATED AREA OF SHOWERS AND STORMS HAS BEEN CLOSELY ASSOCIATED WITH A VORT MAX PROGGED WELL IN THE RUC MODEL. THE VORT MAX CONTINUES TO WEAKEN AS IT PUSHES TO THE NORTHWEST AND AS EXPECTED SHOWERS ARE WEAKENING AS WELL...WITH JUST A FEW LIGHTNING STRIKES REMAINING. THINK MOST OF TODAY WILL BE DRY ACROSS SOUTH TEXAS WITH JUST SOME ISOLATED LIGHT SHOWERS POSSIBLE WITH ADDITIONAL WEAK SHORT WAVES PROPAGATING AROUND MAIN TROUGH. MODEL SOUNDINGS INDICATE SIGNIFICANT CLEARING EVEN POSSIBLY IN WESTERN CWA. THIS WOULD ALLOW TEMPERATURES IN WEBB COUNTY TO INCREASE QUITE A BIT...CURRENTLY FORECASTING HIGHS IN THE MID 90S...BUT CAN`T DISCOUNT THE POSSIBILITY OF SOME AREAS GETTING A COUPLE OF DEGREES WARMER IF SKIES CLEAR. WITH LLJ NOT WEAKENING MUCH THROUGH THE DAY TODAY SHOULD MIX DOWN SOME GUSTS TO AROUND 40MPH THIS AFTERNOON SO HAVE ISSUED WIND ADVISORY FOR EASTERN HALF OF FORECAST AREA. THE FOCUS OF THE SHORT TERM FORECAST RESIDES IN THE POTENTIAL FOR THUNDERSTORMS TONIGHT AS THE COLD FRONT APPROACHES. INGREDIENTS LOOK DECENT FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY IN THE NORTHERN COUNTIES. SOUTHERN BRANCH OF SPLIT UPPER JET IS PROGGED A BIT FARTHER SOUTH TONIGHT THAN MODEL GUIDANCE WAS INDICATING LAST NIGHT. THIS SHOULD HELP THE CAUSE FOR DEVELOPMENT. WIND THREAT WOULD BE THE GREATEST SEVERE THREAT...AS 40-50KT LOW LEVEL JET WILL BE DIRECTLY OVERHEAD TONIGHT COINCIDING WITH THE THUNDERSTORMS. WITH SLIGHTLY SLOWER TIMING OF TROUGH...BEST CHANCE FOR SEVERE WILL BE AFTER MIDNIGHT ACROSS THE AREA...WITH THE NORTH AND NORTHEAST PART OF THE FORECAST AREA BEING THE MAIN TARGET. MODEL SOUNDINGS FOR VICTORIA INDICATE 1500J/KG CAPE OVERNIGHT...WITH LI/S AROUND -5. LAPSE RATES ARE ONLY MODERATE IN THIS REGION HOWEVER...IN THE 5-7C/KM RANGE. HAVE INCLUDED SEVERE WORDING ON FORECAST MAINLY FOR THE NORTHERN 2/3 OF THE FORECAST AREA. SPC HAS A SLIGHT RISK FOR SEVERE WEATHER ACROSS MOST OF THE FORECAST AREA...WITH A MODERATE RISK IN CENTRAL TEXAS. LONG TERM (TUESDAY THROUGH SUNDAY)...MAIN ISSUE THIS FORECAST PACKAGE IS WHETHER TO PLACE POPS IN AFTER TUESDAY AFTERNOON...WITH GENERALLY KEEPING SIMILAR POPS FOR TUESDAY AS ADVERTISED IN PREVIOUS PACKAGES. SPC HAS SLIGHT RISK ON BORDER OF AREA FOR DAY 2...AND WILL GENERALLY NOT SWAY FROM THIS). MODELS HAVE BEEN SHOWING THAT...AFTER THE MCS COMES ACROSS ON TUESDAY (NSSL AND NCEP WRF MODELS ARE KEEPING BIG CONVECTION TO THE NORTH THROUGH 12Z TUESDAY AND EXTRAPOLATION KEEPS THEM NORTH)...SOME DRYING OCCURS TUESDAY AFTERNOON UP TO 850 MB THEN SOME WRAP-AROUND MOISTURE FROM THE 700-300 MB LAYER COMES IN DURING THE LATE AFTERNOON THROUGH TUESDAY NIGHT (DRYING FROM WEST TO EAST AFTER MIDNIGHT TUESDAY EVENING). THIS IS A POTENT UPPER SYSTEM...AND MODELS FOR DAYS HAVE BEEN TOYING WITH POSSIBLE ADDITIONAL RAINFALL TUESDAY NIGHT. GIVEN THE FACT THE MODEL CONSENSUS IS SLOWING UPPER SYSTEM DOWN SOME...AND GUIDANCE IS GOING NEARLY LIKELY ON THE RAINFALL (THINK THIS IS OVER-DONE)...HAVE DECIDED TO INCLUDE POPS TUESDAY NIGHT MAINLY OVER THE EASTERN HALF OF CWFA. COULD EVEN SEE SOME THUNDER OVER THE EXTREME EASTERN AREAS/GULFMEX TUESDAY NIGHT. FARTHER WEST...SPRINKLES AT BEST. AFTER TUESDAY NIGHT...THINK UPPER SYSTEM WILL BE FAR ENOUGH NORTH AND SUFFICIENT DRYING OVER THE AREA TO END RAIN (GFS-MOS STILL HAS CHANCE POPS EASTERN AREAS BUT WILL IGNORE THIS). MODELS ARE RELATIVELY CONSISTENT UNTIL THE END OF THE WORK WEEK IN KEEPING A WEAK UPPER RIDGE OVER THE AREA...THEN DIVERGE OVER THE WEEKEND WITH THE GFS PUSHING THE RIDGE EAST AND MOVING A TROUGH TOWARD THE WESTERN CWFA LATE SUNDAY. THE ECMWF HOWEVER KEEPS THE RIDGE OVER THE AREA (BUT NOT BRINGING A BOUNDARY DOWN LIKE IT DID ON YESTERDAY`S 00Z RUN). FOR NOW...WILL KEEP THE FORECAST RAIN-FREE BUT BRING IN THE MOISTURE A LITTLE FASTER THAN BEFORE AND INCREASE OVERNIGHT TEMPERATURES SOME. OVERALL...TENDED TO GO MORE WITH THE WARMER FORECAST NUMBERS THROUGH THURSDAY MORNING...THEN OVERALL DID A CONSENSUS FORECAST BETWEEN THE ECMWF AND GFS SOLUTIONS FOR TEMPERATURES AND MOST OTHER PARAMETERS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 85 72 83 54 75 / 20 50 60 30 10 VICTORIA 81 70 74 53 72 / 40 70 80 40 10 LAREDO 94 68 83 53 81 / 20 40 20 10 10 ALICE 87 72 82 53 78 / 20 50 50 20 10 ROCKPORT 78 71 78 56 72 / 30 50 70 40 10 COTULLA 89 62 77 49 78 / 30 70 30 10 10 KINGSVILLE 87 71 83 52 77 / 20 50 50 30 10 NAVY CORPUS 79 71 81 57 73 / 20 50 70 40 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...GOLIAD...JIM WELLS...KLEBERG...LIVE OAK...NUECES...REFUGIO...SAN PATRICIO...VICTORIA. GM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. && $$ PZ/83...SHORT TERM GW/86...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 AM CDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 339 AM CDT MON MAR 19 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES AND HOW WARM TO GO WITH TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING OVER THE WESTERN U.S. AND STRONG RIDGING FROM THE SOUTHEASTERN U.S. INTO THE WESTERN GREAT LAKES REGION. WITHIN THE SOUTH-SOUTHWEST FLOW AHEAD OF THE TROUGH...IT IS TOUGH TO FIND ANY SHORTWAVES OF NOTE ON WATER VAPOR. THIS IS PRIMARILY DUE TO PLENTIFUL PACIFIC MOISTURE AND BLOW-OFFS FROM EVENING CONVECTION OVER THE SOUTHERN PLAINS. RUC ANALYSIS SHOWS VERY FEW AS WELL. AHEAD OF THE DEEP TROUGH...A SOUTHWEST 40-60 KT 850MB JET EXISTS OVER THE PLAINS INTO THE FORECAST AREA...HELPING TO MAINTAIN A CONTINUOUS FEED OF MOISTURE TRANSPORT FROM THE GULF OF MEXICO. PRECIPITABLE WATER VALUES ON 00Z SOUNDINGS REFLECT THE MOISTURE TRANSPORT... RANGING FROM 1-1.3 INCHES FROM GRB TO OAX...DVN...TOP AND FWD. THESE ARE 250-310 PERCENT ABOVE NORMAL. DESPITE ALL OF THIS MOISTURE... THERE IS VERY LITTLE OCCURRING ON REGIONAL RADARS...AND AGAIN THIS MIGHT BE DUE TO LACK OF NOTABLE SHORTWAVE FEATURES. IN ADDITION...ALTHOUGH THE ENVIRONMENT HAS A LOT OF MOISTURE WITH RESPECT TO NORMAL...00Z SOUNDINGS FROM OAX...DVN AND MPX WERE ACTUALLY FAIRLY DRY OUTSIDE OF THE 800MB MOISTURE JUST BELOW THE CAP. NEAREST PRECIPITATION ON RADAR IS IN MISSOURI AND WESTERN KANSAS. THE BREEZY SOUTHERLY FLOW...AHEAD OF A 982MB LOW IN EASTERN MONTANA...HAS HELPED TO KEEP TEMPERATURES UP IN THE 60S AND DEWPOINTS IN THE MID TO UPPER 50S. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE UPPER LEVEL PATTERN THROUGH THE SHORT TERM...ALL SHOWING THE CURRENT WESTERN TROUGH MOVING INTO THE WESTERN PLAINS ON TUESDAY...THEN SPLITTING APART. THE MAIN TREND IS THAT THE SOUTHERN END WHICH CUTS OFF INTO AN UPPER LOW IS FARTHER SOUTH AND WEST FOR WEDNESDAY AND WEDNESDAY NIGHT. THIS RESULTS IN RIDGING BUILDING BACK WESTWARD INTO THE FORECAST AREA WEDNESDAY NIGHT. DESPITE THE GOOD AGREEMENT ON THE UPPER PATTERN...DETAILS ARE MURKY AT BEST...ESPECIALLY WHEN IT COMES TO PRECIPITATION. THE REASONS ARE TWO FOLD: 1. HAVING THE ABNORMALLY HIGH MOISTURE STREAM EXPECTED TO STAY PUT OVER THE FORECAST AREA THROUGH THE SHORT TERM PERIOD...AND 2. ANY WEAK SHORTWAVE FORCING COULD ACT ON THE MOISTURE STREAM AND CAUSE PRECIPITATION TO OCCUR. THE DAILY DISCUSSIONS BELOW REPRESENT THE BEST ATTEMPT TO FIGURE OUT THE DETAILS. TODAY AND TONIGHT...THERE ARE INDICATIONS BY THE 19.00Z NAM/GFS/REGIONAL CANADIAN OF A WEAK SHORTWAVE COMING OUT OF MISSOURI AND LIFTING NORTHEAST THROUGH THE FORECAST AREA TODAY. THE NAM AND GFS BOTH PRODUCE PRECIPITATION WITH THIS SHORTWAVE...LIKELY OCCURRING IN THE 15-21Z TIME PERIOD...WHEREAS THE REGIONAL CANADIAN ONLY PRODUCES PRECIPITATION NEAR GRANT COUNTY. THE 19.03-19.05Z HRRR RUNS HAVE LOOKED A LOT LIKE THE REGIONAL CANADIAN AS WELL...GIVING A LITTLE MORE CONFIDENCE TOWARDS A DRIER SOLUTION. GIVEN THE FACT THAT IT IS TOUGH TO FIND ANY NOTABLE SHORTWAVE IN WATER VAPOR AND THE DRIER 00Z SOUNDING LOOK...HAVE LOWERED PRECIPITATION CHANCES TODAY TO MOSTLY 20-40 PERCENT. DOES SEEM THAT THE AFTERNOON WOULD HAVE BETTER POTENTIAL GIVEN THAT MUCAPE VALUES COULD RANGE FROM 500-1500 J/G...SO THE 40 PERCENT EXIST THEN. STILL...IT IS HARD TO FIND A TRUE TRIGGER IN THE AFTERNOON WITH LITTLE IF ANY HEIGHT FALLS OR SHORTWAVE COMING ACROSS. NOTE THAT WHERE THE HIGHEST CAPE EXISTS...0-6/0-3KM SHEAR IS LESS THAN 25 KT...SUGGESTING STORM ORGANIZATION AND SEVERE WEATHER IS NOT ANTICIPATED. ANOTHER ROUND OF PRECIPITATION WHICH LOOKS MORE CERTAIN WILL MOVE INTO AREAS WEST OF THE MISSISSIPPI RIVER THIS EVENING. THIS PRECIPITATION IS ASSOCIATED WITH A DEEPER WARM CONVEYOR BELT SURGE COMING OUT OF THE SOUTHERN PLAINS. HOWEVER...A LOT OF UNCERTAINTY EXISTS IF THE PRECIPITATION WILL MOVE EAST OVERNIGHT AND HOW MUCH OF IT STAYS INTACT. THE REASON FOR THIS UNCERTAINTY IS THAT IT APPEARS THE WARM CONVEYOR MAY SPLIT APART AS IT PUSHES EAST INTO THE UPPER RIDGING...LIKE THE SPLIT OCCURRING WITH THE WESTERN UPPER TROUGH. THEREFORE FOR TONIGHT BEST CHANCES FOR PRECIPITATION...IN THE 60-70 RANGE...WILL STAY WEST OF THE MISSISSIPPI RIVER. TUESDAY THROUGH WEDNESDAY NIGHT...WITH THE TREND FOR THE UPPER LEVEL TROUGH TO SPLIT SOONER...THE OVERALL FORECAST FOR THIS TIME PERIOD LOOKS DRIER...ESPECIALLY FOR WISCONSIN. PRECIPITATION FORECASTS THAT WERE MOSTLY OVER THE AREA HAVE NOW SHIFTED WEST TO HANDLE THE FARTHER WEST UPPER TROUGH AND SURFACE COLD FRONT. AS SUCH...CHANCES HAVE BEEN REDUCED. REGARDING A FEW DETAILS...TUESDAY MORNING COULD BE QUIET AS DEPICTED BY THE REGIONAL CANADIAN AND GFS...RESULTING FROM THE WARM CONVEYOR BELT FALLING APART. THIS IS ONLY TEMPORARY BECAUSE IN THE AFTERNOON A NEW SURGE OF SHOWERS AND EMBEDDED THUNDER SHOULD COME UP THROUGH THE WEST HALF OF IOWA AND POSSIBLY ENTER SOUTHEAST MINNESOTA. VERY GOOD AGREEMENT EXISTS ON THIS...RESULTING FROM A SHORTWAVE EJECTING OUT OF THE UPPER TROUGH. FOR TUESDAY NIGHT...THIS SURGE OF PRECIPITATION AGAIN LOOKS TO STAY MORE TO OUR WEST AND NORTHWEST...AGREED TOO WITH THE NEW 19.00Z ECMWF. IT IS CONCEIVABLE NOW THAT WEDNESDAY ENDS UP DRY AS UPPER LEVEL AND FRONTOGENETICAL FORCING WANES...BUT FOR NOW HAVE MAINTAINED SOME LOW CHANCES PER CONTINUITY AND STILL SOME WEAK FORCING INDICATIONS. THAT FRONTOGENETIC FORCING MAY TRY TO STRENGTHEN BACK UP WEDNESDAY NIGHT IF THE UPPER LOW KICKS OUT AS PROGGED. THUS HIGHER CHANCES ARE INDICATED THEN. REGARDING TEMPERATURES THROUGHOUT THE SHORT TERM...GIVEN THE PERIODIC ROUNDS OF PRECIPITATION...HIGHS ARE DIFFICULT TO FORECAST. 850MB TEMPS HOLD BETWEEN 10-12C AND THE TRUE SURFACE COLD FRONT... WHICH LOOKS LIKE IT ENDS UP FALLING APART...DOES NOT MOVE INTO THE AREA UNTIL WEDNESDAY NIGHT. IF ANY SUN OCCURS...TEMPERATURES COULD EASILY JUMP WELL INTO THE 70S AND POSSIBLY LOW 80S. FOR NOW STAYED WITH A BLEND OF GUIDANCE WHICH DID CAUSE AN INCREASE IN HIGHS FOR TUESDAY AND WEDNESDAY...RESULTING TOO FROM THE UPPER TROUGH SLOWING DOWN. LOWS ARE LIKELY TO REMAIN IN THE 50S TO LOW 60S...WARMEST TONIGHT. SEE CLIMATE SECTION BELOW FOR POSSIBLE RECORDS. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 339 AM CDT MON MAR 19 2012 OVERALL MUCH BETTER AGREEMENT EXISTS TODAY AMONGST THE 19.00Z GUIDANCE WITH THE HANDLING OF THE UPPER LEVEL PATTERN...INCLUDING THE UPPER LOW. IF ANYTHING...THE ECMWF HAS TRENDED COMPLETELY TOWARDS PAST AND CURRENT GFS RUNS...WHICH SUGGESTS A CONTINUATION OF ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THIS ALSO MATCHES CFS FORECASTS WHICH SUGGESTS THE SAME FOR THE MARCH 24TH THROUGH 28TH PERIOD. MAIN FOCUS FOR MUCH OF THE LONG TERM PERIOD IS ON THE UPPER LOW OVER THE SOUTHERN PLAINS WEDNESDAY NIGHT. GOOD AGREEMENT EXISTS THAT IT WILL LIFT NORTHEAST INTO NORTHERN MISSOURI BY FRIDAY IN RESPONSE TO DIGGING TROUGHING OFF THE U.S. WEST COAST. A WARM CONVEYOR BELT OF PRECIPITATION LOOKS TO FORM AHEAD OF THIS LOW AND IMPACT THE AREA THURSDAY AND THURSDAY NIGHT...POSSIBLY FRIDAY AS WELL IF THE GFS IS CORRECT. SIMILAR TO THE SHORT TERM PERIOD...PRECIPITABLE WATER VALUES ARE WELL ABOVE NORMAL...300 TO 350 PERCENT OR SO. RAISED PRECIPITATION CHANCES TO 40-50 AND FURTHER INCREASES MAY BE NECESSARY. SOME SHOWERS COULD STILL PERSIST FOR FRIDAY NIGHT AND SATURDAY AS THE UPPER LOW SCOOTS OFF TO THE EAST...AND WHILE THERE IS A RELATIVE COOL POOL OF AIR ALOFT. ANTICIPATING DRY CONDITIONS FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UPPER RIDGING BUILDING OVER THE PLAINS IN THE WAKE OF THE UPPER LOW...AS WELL AS SURFACE RIDGING BUILDING IN AT THE SURFACE. BACK TO TEMPERATURES...DESPITE THE APPROACH OF THE UPPER LOW FOR THURSDAY AND FRIDAY AND ITS ASSOCIATED PRECIPITATION...BOTH MEX AND 19.00Z ECMWF 2 METER GRID GUIDANCE HAVE REALLY WARMED UP THIS TIME PERIOD. IN FACT...THE ECMWF SUGGESTS POTENTIAL FOR RECORD HIGHS ON THURSDAY. GIVEN THE FACT THAT THE ECMWF DOES CONSIDER PRECIPITATION IMPACTS ON TEMPERATURES...HAVE RAISED TEMPERATURES SOME OVER THE BLEND OF GUIDANCE. FURTHER INCREASES MAY BE NECESSARY. SHOULD SEE SOMEWHAT OF A COOL DOWN FOR THE WEEKEND...BUT 850MB TEMPS ONLY DROP TO 4-6C AT MOST. THIS WILL KEEP READINGS ABOVE NORMAL. && .AVIATION...TODAY AND TONIGHT 645 AM CDT MON MAR 19 2012 FAIRLY COMPLICATED FORECAST SETUP TODAY AND TONIGHT. CURRENTLY... THE AREA IS ENTRENCHED IN MOIST/SOUTHERLY AIRLFOW AHEAD OF A COLD FRONT IN PLACE ACROSS THE PLAINS. THIS IS SENDING VFR CLOUDS INTO THE REGION WITH RADAR FAIRLY QUIET AT THE MOMENT. CLOUDS WILL BE ON THE INCREASE TODAY AS MOISTURE CONTINUES TO SPREAD INTO THE AREA. MODEL SOUNDINGS SHOWING INSTABILITY INCREASING AS WELL FOR SCATTERED SHRA/ISOLATED THUNDER. CLOUD BASES EXPECTED TO REMAIN VFR. DUE TO LACK OF A GOOD TRIGGER FOR CONVECTION AND THE LIMITED INSTABILITY...KEPT VCSH/CB IN THE KLSE/KRST TAF SITES FROM 18Z- 23Z. FOR TONIGHT...THE COLD FRONT MOVES INTO WESTERN MN/IA. THIS WILL SERVE TO FOCUS BETTER PLUME OF MOISTURE TRANSPORT AND LIKELIHOOD OF SHRA/TS INTO THE AREA. FELT CONFIDENT ENOUGH TO INCLUDE SHRA IN TAFS AFTER 06Z BASED ON THIS SIGNAL. LOOKING AT CIGS/VIS TO SLIP INTO MVFR RANGE AT KRST AFTER 06Z WHILE KLSE EXPECTED TO REMAIN VFR. OTHERWISE...BREEZY SOUTH WINDS WILL BE SEEN AGAIN TODAY WITH GUSTS IN THE 25 TO 35KT RANGE. && .CLIMATE...THIS WEEK 339 AM CDT MON MAR 18 2012 TEMPERATURES LOOK TO GRADUALLY COOL THIS WEEK WITH PERIODS OF PRECIPITATION EXPECTED EACH DAY. HOWEVER...THIS PROCESS IS GOING TO BE VERY SLOW AS THE UNSEASONABLY WARM AIRMASS NEVER GETS FULLY SHUNTED EAST OF HERE UNTIL MAYBE THIS WEEKEND ACCORDING TO LATEST MODEL GUIDANCE. THEREFORE...POTENTIAL EXISTS EACH DAY FOR RECORD HIGHS AND MORE LIKELY RECORD HIGH MINIMUMS. CURRENT FORECAST PLAYS TEMPERATURES A LITTLE CONSERVATIVELY. IF MORE SUN OCCURS THAN FORECAST FOR TODAY...TUESDAY OR WEDNESDAY...RECORDS HIGHS ARE MORE LIKELY TO BE BROKEN. WEDNESDAY MAY BE THE TOUGHEST DAY TO BREAK RECORD HIGHS WITH MOST LOCATIONS HAVING RECORDS BETWEEN 75 TO 80...EXCEPT ROCHESTER AND MEDFORD WHICH ARE AT 70. FOR A LIST OF WHAT HAS OCCURRED REGARDING RECORDS THUS FAR AS WELL AS THOSE THAT COULD FALL IN THE DAYS TO COME...PLEASE SEE THE TOP NEWS STORY ON OUR WEBSITE ON THE UNSEASONABLY WARM MARCH. && .ARX WATCHES/WARNINGS/ADVISORIES... 339 AM CDT MON MAR 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DAS CLIMATE......AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
612 AM CDT MON MAR 19 2012 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY THROUGH TUESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AMPLIFIED UPPER PATTERN ACROSS THE CONTINENT EARLY THIS MORNING...WITH A LARGE UPPER TROUGH OVER THE INTER-MOUNTAIN WEST AND SUBTROPICAL RIDGING CENTERED OVER THE CENTRAL GREAT LAKES. A LARGE PLUME OF MOISTURE IS HEADING NORTHEAST OVER THE GREAT PLAINS THOUGH PRECIP ECHOES ARE WIDELY SCATTERED OVER MISSOURI AND KANSAS. ONE SHORTWAVE OF NOTE IS EMBEDDED IN THE SW TROPICAL FLOW OVER KANSAS...BUT IS FAIRLY INACTIVE AT THE MOMENT. PLENTY OF CAPPING IN PLACE AS DEPICTED ON 00Z RAOBS OVER THE REGION. CLOSER TO HOME...AREA OF 6-7KFT CU HAS BEEN EXPANDING OVER FAR NE WISCONSIN AND THE EASTERN UPPER PENINSULA. AS MOISTURE STREAMS INTO THE REGION FROM THE CENTRAL PLAINS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN OVER THE NEXT 36 HOURS. TODAY...LARGE TROUGH OVER THE WEST WILL SLOWLY SLIDE ACROSS THE ROCKIES WHILE MID-LEVEL RIDGING WILL BUILD OVER THE CENTRAL GREAT LAKES. SLUG OF TROPICAL MOISTURE FROM THE SOUTHERN PLAINS WILL LIFT NORTH INTO WISCONSIN LATE IN THE MORNING AND THROUGH THE AFTERNOON...WITH PWATS CLIMBING TO GREATER THAN 1.25 INCHES...WHICH IS NEAR THE HIGHEST ON RECORD FOR THE MONTH OF MARCH. AS THE COLUMN MOISTENS...MODELS PROJECT THE STRONG CAP IN PLACE ACROSS THE REGION PARTIALLY ERODES...THOUGH THE NAM COMPLETELY WIPES IT OUT. BASED ON UPSTREAM SOUNDINGS...DO NOT THINK THIS IS REASONABLE. INSTEAD...WILL GO MORE WITH THE GFS IDEA OF KEEPING A WEAKENED CAP AROUND. BUT EVEN WITH A WEAKENED CAP...MODIFIED PROGGED SOUNDINGS OVER CENTRAL WISCONSIN USING A 74/58 PARCEL YIELDS ABOUT 900 J/KG OF ML CAPE AND NO CIN. WILL HAVE TO GET TO THE MIDDLE 70S TO REACH THE CONVECTIVE TEMPERATURE TO GET PAST THE CAP THIS AFTERNOON. LACK OF UPSTREAM ECHOES AND TRIGGERS LEADS ME TO GO DRY ACROSS MOST OF THE AREA THROUGH THE MORNING. IMPULSE OVER KANSAS SHOULD APPROACH THE REGION IN THE AFTERNOON WHICH COULD INTERACT WITH DAYTIME INSTABILITY TO CREATE SCT SHOWERS AND TSTORMS. STILL NOT THINKING ANYTHING SEVERE TODAY...BUT SOME OF THE STRONGEST STORMS COULD PRODUCE SMALL HAIL AND BRIEF GUSTY WINDS. WILL HAVE MORE CLOUD COVER AND MOISTURE AROUND THAN YESTERDAY...THOUGH LOOK TO BE OFF TO A WARMER START THAN YESTERDAY TOO. WILL GO WITH TEMPS A DEGREE OR TWO COOLER. TONIGHT...THE AIRMASS CHANGES VERY LITTLE AS THE DEEP TROUGH OVER THE WESTERN HARDLY MOVES TO THE EAST. AS MOIST AS THE COLUMN APPEARS...WOULD NOT TAKE MUCH OF A FEATURE OR SHORTWAVE IMPULSE TO TRIGGER SHOWERS AND ISOLD TSTORMS. WILL KEEP A MENTION OVER THE WESTERN 2/3RDS OF THE FORECAST AREA. SHOULD SEE A WARMER AND MORE MUGGY NIGHT...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S AWAY FROM LAKE MICHIGAN. TUESDAY...SOUTHERN PIECE OF THE WESTERN TROUGH CUTS OFF OVER WESTERN TEXAS WHILE SURFACE LOW PRESSURE TRAVELS NORTH OVER THE CENTRAL PLAINS. COLD FRONT ATTACHED TO THE LOW WILL SUBTLY SHIFT EAST TO THE MN/WI BORDER BY LATE IN THE AFTERNOON. AIRMASS CHANGES VERY LITTLE...BUT PROGGED SOUNDINGS SHOW SOME DRYING IN THE MID-LEVELS THAT LEADS TO SLIGHTLY LESS INSTABILITY THAN PROGGED FOR TODAY. THAT WONT LEAD TO A BIG CHANGE (IF ANY) IN THE FORECAST THOUGH AND WILL KEEP POPS ACROSS THE WESTERN 2/3RDS OF THE FORECAST AREA. HIGHS PERHAPS A FEW DEGREES COOLER OVER NORTH-CENTRAL WISCONSIN DUE TO CLOUD COVER AND POTENTIAL PRECIP...THOUGH LITTLE CHANGE IN TEMPS FARTHER EAST. .LONG TERM...TUESDAY NIGHT THRU SUNDAY. MAIN FORECAST CONCERNS ARE TEMPS AND PRECIP CHANCES. HIGHLY AMPLIFIED PATTERN WHICH HAS DOMINATED FOR THE PAST SEVERAL DAYS WITH A DEEP TROUGH OVER THE WESTERN U.S. AND RIDGING OVER THE EASTERN U.S. WILL SLOWLY TRANSITION TO MORE OF A SPLIT FLOW AS CUT OFF UPPER LOW SITS AND SPINS IN THE SOUTHERN PLAINS AND MORE OF A ZONAL FLOW DEVELOPS ACROSS THE NORTHERN U.S. AND SOUTHERN CANADA. MODEL TRENDS HAVE BEEN TO STALL THE UPPER LOW WELL TO OUR SW...KEEPING WARMER TEMPS ACROSS THE AREA LONGER...AND HOLDING OFF BEST PRECIP CHANCES UNTIL LATER THIS WEEK. PINNING DOWN BEST CHANCES FOR PRECIP WILL BE VERY CHALLENGING AS MODELS HAVE NOT REMAINED CONSISTENT ENOUGH TO HAVE CONFIDENCE IN ANY ONE SOLUTION. DUE TO THE MUCH SLOWER EASTWARD PROGRESSION OF THE UPPER LOW AS ADVERTISED BY THE LAST COUPLE OF MODEL RUNS... HAVE MADE SOME SIGNIFICANT CHANGES TO THE POPS AND CLOUDS GRIDS FOR MID-WEEK. FIRST CHANCE OF PRECIP WILL COME TUESDAY NIGHT AND WEDNESDAY AS FRONT CROSSES INTO THE STATE. STILL SOME UNCERTAINTY WITH HOW FAR SOUTH THE FRONT WILL GET. DECIDED TO PULL POPS FOR ALL BUT FAR NORTH-CENTRAL WI TUESDAY NIGHT...AND CHOPPED WEDNESDAY POPS TO CHANCE ACROSS CENTRAL AND NORTH-CENTRAL WI AND SLIGHTS OVER THE EAST...FAVORING A SLOWER SOLUTION...PLUS THE BEST FORCING WILL REMAIN CLOSER TO A UPPER JET NORTH OF THE REGION. REDUCED CLOUDS MAINLY ACROSS EASTERN WI AS WELL. MODELS HAVE HELD MOST OF THE ACTIVITY WITH THIS SYSTEM NW OF THE CWA...SO WOULD NOT BE SURPRISED IF WE MISS OUT ON THIS SYSTEM COMPLETELY IN THE SE...AND WILL ONLY KEPT THE SLIGHT CHANCE POPS TO COVER ANY ISOLATED ACTIVITY OUT AHEAD OF THE FRONT IN THE PERSISTENT MOIST SOUTH FLOW. HAVE INCREASED POPS FOR LATE IN THE WEEK AS MODELS NOW SHOW THE UPPER LOW WORKING INTO THE SOUTHERN GREAT LAKES...BUT CONFIDENCE REMAINS LOW AS HOW QUICKLY THE UPPER LOW WILL TOWARD THE AREA. WILL CONFINE THUNDER MENTION FOR THE DAYTIME HOURS... MAINLY THE AFTERNOON...ALTHOUGH CONVECTIVE PARAMETERS NOT VERY IMPRESSIVE WITH CLOUD COVER REDUCING INSTABILITY AND LAPSE RATES NOT TOO STEEP. THE RECORD BREAKING...OR NEAR RECORD BREAKING...WARMTH LOOKS TO CONTINUE INTO WEDNESDAY NOW...WITH 850/925MB TEMPS STILL SUPPORTIVE OF HIGHS IN THE MIDDLE TO UPPER 70S ACROSS EAST-CENTRAL WI. SLIGHTLY COOLER TEMPS ALOFT AND MORE CLOUDS EXPECTED AS YOU WORK TOWARD NW AND NORTH-CENTRAL WI...AS THE FRONT SAGS ACROSS THE STATE...SO EXPECT COOLER TEMPS THERE. THICKER CLOUD COVER AND/OR THE FRONT SAGGING FARTHER SOUTH COULD KEEPS TEMPS COOLER ACROSS THE AREA...HOWEVER FAVOR THE WARMER TEMPS. ABOVE NORMAL TEMPS ARE EXPECTED THROUGH THE UPCOMING WEEKEND...WITH NO COLD AIR IN SIGHT FOR THE AREA. EVEN AS UPPER LOW COMES CLOSER...IT SEEMS TO LOSE ITS SOMEWHAT CHILLY CORE...SO WILL BUMP UP TEMPS A LITTLE LATE IN THE WEEK. && .AVIATION...A LARGE PLUME OF MOISTURE WILL SURGE NE OUT OF THE PLAINS AND ACROSS THE STATE TODAY. THUNDERSTORMS MOVING INTO NW ILLINOIS WOULD REACH THE SOUTHERN FOX VALLEY LATE THIS MORNING...BUT WILL NOT EXPLICITLY ADD TO TAFS SINCE ITS STILL A LONG WAYS OUT. SKY CONDITIONS WILL BE BKN THOUGH VFR FROM ABOUT MID-MORNING ONWARD. AS THIS MOISTURE ARRIVES...CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASES LATE THIS MORNING THROUGH THE REST OF THE TAF PERIOD. BEST CHANCES OF PRECIP WILL BE OVER CENTRAL WISCONSIN...BUT UNCERTAINTY ABOUT COVERAGE MAKES GOING VCSH ABOUT THE BEST WE CAN DO AT THIS POINT. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
415 PM EDT MON MAR 19 2012 .SHORT TERM... /THROUGH TONIGHT/ ISOLATED SHOWERS POPPING HERE AND THERE ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. MOST PERSISTENT AND STRONGEST STORM DEVELOPED IN SOUTHERN LAPORTE COUNTY AND HAS BEEN REDEVELOPING SE WITH TIME AS THE STORM CYCLES. THIS STORM WILL MOVE TOWARDS SOUTH BEND OVER THE NEXT HOUR OR SO WITH LOCALLY HEAVY RAIN AND POSSIBLY SOME SMALL HAIL. OTHERWISE...ADDITIONAL SHOWERS AND THUNDERSTORMS WERE FORMING UPSTREAM ACROSS EC ILLINOIS INTO FAR WESTERN INDIANA. SFC BASED CAPES OF 2000 J/KG AND LI`S TO -6 C WERE IN PLACE ACROSS THE AREA. HRRR FIRES EVEN MORE CONVECTION WITH TIME INTO EARLY EVENING ACROSS MUCH OF THE AREA. THINK HRRR MAY BE A BIT OVERDONE ON ITS COVERAGE...BUT WILL NEED TO WATCH FOR EXPANDING COVERAGE AS OUTFLOW BOUNDARIES FROM ST JOE COUNTY CONVECTION MAY EXPAND COVERAGE SOMEWHAT. ACTIVITY SHOULD DECREASE BY EARLY EVENING AS LOSS OF DAYTIME HEATING OCCURS AND BOUNDARY LAYER BEGINS TO COOL. DRY CONDITIONS WILL THEN BE IN STORE FROM MID EVENING INTO THE OVERNIGHT HOURS WITH LOWS DROPPING BACK INTO THE MID TO UPPER 50S. SOME PATCHY FOG IS POSSIBLE ONCE AGAIN...ESPECIALLY IN AREAS THAT SEE ANY RAINFALL OVER THE NEXT SEVERAL HOURS. WILL LEAVE MENTION OUT OF THE ZONES FOR THE TIME BEING. && .LONG TERM... TUESDAY THROUGH MONDAY. FEW CHANGES TO AFFORD WRT MED-LONG TERM FCST PD. CENTROID OF STALWART RIDGE AMASSES INTO WRN OH BY WED EVE. CONTINUED STRONG INSOLATION AMID STAGNANT AIRMASS CONTS TO SUPPORT PROGRESSIVELY WARMER TEMPS INTO WED WITH WED AFTN LKLY WARMEST...DARE I SAY HOTTEST AS LLVL THERMAL FIELD REACHES APEX. CONT TO WHITTLE AWAY AT LAKE SHADOW AS STRONG SRLY FLOW TO KEEP DTC RESPONSE OFFSHORE. WITH INCREASED AGREEMENT WRT TIMING OF 5H CUTOFF HOLDING SOUTH OF TEXAS RED RIVER VALLEY THROUGH 18 UTC WED...THEREAFTER ONLY SLOWLY LIFTING NEWD TO KS/MO BORDER FRIDAY MORNING BEFORE TAKING ON A MORE ERLY EXODUS AS NEXT EPAC TROF DIGS AND IMPARTS DOWNSTREAM BROAD FLAT RIDGING FM WRN TX TO ERN MT/DAKOTAS. GIVEN SLOWER TREND OF MID/UL PATTERN HAVE REMOVED POPS THU AMID POOR MID LVL LAPSE RATES AND ACYCLONIC MIDLVL FLOW AND ABSENCE OF PARTICULAR FOCI. TRENDED POPS HIR ON FRIDAY AS MIDLVL COLD POOL NEARS WITH MORE FAVORABLE CLOSED CORE LOW CONCEPTUAL MODEL. INCRSD DIVERGENCE BYND DY6 THOUGH TEND TO FAVOR MORE SERLY TURN OF ECMWF. GIVEN BREADTH AND SLOW ERLY PROGRESSION INTO HIGH HGHT ANOMALY...SUSPECT ABOVE NORMAL TEMPS ERLY NEXT WEEK TO ONCE AGAIN SEGUE INTO A PD OF MUCH ABOVE NORMAL TEMPS. && .AVIATION /18 UTC TAFS/... INSTABILITY INCREASING ACROSS THE AREA WITH CU FIELD EXPANDING IN SEVERAL PARTS OF THE REGION. A FEW SHOWERS HAVE BEGUN TO DEVELOP WITH THE STRONGEST CURRENTLY BETWEEN TAF SITES. LACK OF STRONG FORCING AND CONVERGENCE WILL CAUSE COVERAGE OF ANY CONVECTION TO BE ISOL TO SCT AT BEST. INITIAL SURGE OF CONVECTION MAY END UP DEVELOPING OVER BOTH AIRPORTS...MOVING NE WITH TIME. ADDITIONAL CONVECTION MAY FIRE BACK TO THE SW WITH HRRR MODEL HINTING FOR SEVERAL RUNS AT SCT- NUMEROUS SHOWERS/STORMS DEVELOPING BY MID AFTERNOON. WILL STAY CONSERVATIVE FOR THE TIME BEING WITH ONLY CB MENTION AT BOTH SITES. AMENDMENTS MAY BE NEEDED OVER THE NEXT COUPLE OF HOURS AS CONVECTIVE SCENARIO BECOMES CLEARER. AFTER SUNSET...CONVECTION SHOULD QUICKLY WANE LEAVING BEHIND VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...FISHER LONG TERM...MURPHY AVIATION...BENTLEY/FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
136 PM EDT MON MAR 19 2012 .AVIATION... /18Z TAFS/ INSTABILITY INCREASING ACROSS THE AREA WITH CU FIELD EXPANDING IN SEVERAL PARTS OF THE REGION. A FEW SHOWERS HAVE BEGUN TO DEVELOP WITH THE STRONGEST CURRENTLY BETWEEN TAF SITES. LACK OF STRONG FORCING AND CONVERGENCE WILL CAUSE COVERAGE OF ANY CONVECTION TO BE ISOL TO SCT AT BEST. INITIAL SURGE OF CONVECTION MAY END UP DEVELOPING OVER BOTH AIRPORTS...MOVING NE WITH TIME. ADDITIONAL CONVECTION MAY FIRE BACK TO THE SW WITH HRRR MODEL HINTING FOR SEVERAL RUNS AT SCT-NUMEROUS SHOWERS/STORMS DEVELOPING BY MID AFTERNOON. WILL STAY CONSERVATIVE FOR THE TIME BEING WITH ONLY CB MENTION AT BOTH SITES. AMENDMENTS MAY BE NEEDED OVER THE NEXT COUPLE OF HOURS AS CONVECTIVE SCENARIO BECOMES CLEARER. AFTER SUNSET...CONVECTION SHOULD QUICKLY WANE LEAVING BEHIND VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. && .UPDATE... UPDATE MAY BE NEEDED TO ZONES/GRIDS OVER THE NEXT COUPLE OF HOURS AS CU FIELD CONTINUES TO SLOWLY EXPAND ACROSS THE AREA. CU HAS STRUGGLED TO GAIN MUCH HEIGHT...BUT A FEW CELLS HAVE MANAGED TO INCREASE IN HGT WITH STRONGEST CELL CURRENTLY JUST SOUTH OF THE OFFICE WHERE A LIGHTNING STRIKE WAS ALREADY NOTED. OTHER SHOWERS WERE ACROSS STARKE AND PULASKI COUNTY. 14Z HRRR AND PREV RUNS ALL HINTED AT CONVECTION FIRING GENERALLY WHERE IT IS NOW AND PUSHING NE WITH TIME. ADDITIONAL STORMS MAY FIRE SOUTHWEST AND SOUTH OF THE AREA AND MOVE IN MID-LT AFTERNOON. FOR NOW WILL MAINTAIN 20 TO 30 POPS GIVEN COVERAGE. IF COVERAGE INCREASES FURTHER THAN UPDATE WILL BE WARRANTED. LOCALLY HEAVY RAIN AND HAIL TO THREE QUARTERS OF AN INCH IN DIAMETER WILL BE POSSIBLE WITH THE STRONGEST CELLS...ESPECIALLY DURING COLLAPSE OF ANY STORMS. AS FOR TEMPS...FORECAST HIGHS SEEM ON TRACK. HEATING HAS SLOWED A BIT AT KSBN WITH CIRRUS SHIELD COMING OVERHEAD...BUT SHOULD SEE SOME CLEARING AGAIN OVER NEXT HOUR OR 2. RECORD HIGHS ALREADY BROKE AT BOTH SBN AND FWA. && .PREV DISCUSSION... /ISSUED 435 AM EDT MON MAR 19 2012/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT MUCH OF THE SAME FOR BEGINNING OF THE WEEK...WITH FORECAST ATTENTION CENTERED ON RECORD BREAKING WARMTH AND CONVECTIVE POTENTIAL. IN THE VERY NEAR TERM...HAVE ISSUED A DENSE FOG ADVISORY FOR NORTHERN NORTHWEST OHIO COUNTIES AND HILLSDALE COUNTY MICHIGAN. STRONGER RADIATIONAL COOLING ACROSS THESE LOCATIONS EARLIER...COMBINED WITH WEAK EAST SOUTHEAST LOW LEVEL FLOW COMPONENT HAS BEEN CONDUCIVE FOR SOME WESTWARD EXPANSION OF DENSE FOG THAT FORMED WEST OF LAKE ERIE. THIS DENSE FOG MAY NOT MAKE IT AS FAR WEST AS THE FAR WESTERN PORTIONS OF THE COUNTIES IN THE DENSE FOG ADVISORY BUT FOG SATELLITE PRODUCT AND OBSERVATIONS SUGGEST A SLOW WESTWARD EXPANSION OF DENSE FOG OVERNIGHT. THE SLOW MOVING CONVECTIVELY ENHANCED VORT MAX THAT BROUGHT YESTERDAYS PRECIPITATION HAS EXITED INTO EASTERN OHIO THIS MORNING. SOME ISOLATED SHOWERS TRYING TO DEVELOP IN NARROW AXIS OF ENHANCED LOW/MID LEVEL WARM ADVECTION BEHIND THIS DEPARTING VORT MAX FROM SOUTH CENTRAL LOWER MICHIGAN INTO NORTHWEST OHIO. RUC INITIALIZATION SOUNDINGS SUGGEST THESE SHOWERS ARE ELEVATED TO AN EXTENT MAKING IT DIFFICULT TO REALIZE MUCH ELEVATED INSTABILITY. SIMILAR CONCERNS IN TERMS OF MAGNITUDE OF ELEVATED INSTABILITY PERSIST ACROSS WESTERN PORTIONS OF THE AREA...ALTHOUGH SHORT TERM PROGS FROM NAM/RUC SUGGEST WEAK AREA OF SECONDARY LOW LEVEL MOISTURE/THETAE ADVECTION SHIFTING INTO NORTHWEST INDIANA THIS MORNING THAT MAY HELP TO ENHANCE ELEVATED INSTABILITY. A WEAK SHEARED VORT MAX ALSO LIFTING NORTHEASTWARD DOWNSTREAM OF LARGE SCALE WESTERN CONUS TROUGH MAY ALSO PROVIDE SOME WEAK MID/UPPER LEVEL SUPPORT TO GENERATE SOME ISOLD ELEVATED STORMS OVER THE NEXT FEW HOURS. A BETTER CHANCE OF THUNDERSTORMS EXISTS THIS AFTERNOON AND HAVE MADE NO CHANGES TO TSRA CHANCE POPS WEST/SLIGHT CHANCE EAST AS CONTINUED WEAK EMBEDDED WAVES LIFT INTO THE AREA. THE MOST NOTABLE OF THESE SHORT WAVES APPEARS TO BE SITUATED FROM EASTERN MISSOURI INTO NORTHERN ARKANSAS EARLY THIS MORNING. MID LEVEL LAPSE RATES ARE EXPECTED TO STEEPEN TOWARD MIDDAY AS AN ELEVATED MIXED LAYER ADVECTS NORTHEAST INTO THE AREA. SFC TEMPERATURES WARMING TO AROUND 80 THIS AFTERNOON SHOULD COMBINE WITH THESE STEEPER MID LEVEL LAPSE RATES FOR SBCAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. PRESENCE OF MID LEVEL RIDGE/LOW SHEAR WILL KEEP SEVERE THREAT LOW...WITH PERHAPS SLIGHTLY MORE RESPECTABLE 0 TO 6 KM BULK SHEAR VALUES INTO THE 20 TO 25 KNOT RANGE ACROSS WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. WILL MENTION JUST AN ISOLD HAIL/WIND THREAT IN THIS MORNINGS HWO. IN TERMS OF TEMPERATURES...MIXING TO AROUND 900 HPA SHOULD SUPPORT HIGHS FROM THE UPPER 70S TO AROUND 80 WHICH WOULD ONCE AGAIN BREAK THE RECORD HIGHS FOR THE DATE...76 AT FORT WAYNE AND 77 AT SOUTH BEND...BOTH SET IN 1921. UPPER LEVEL TROUGH DIGGING/AMPLIFICATION ACROSS THE ROCKIES WILL RESULT IN DOWNSTREAM MID LEVEL HEIGHT RISES ACROSS THE GREAT LAKES REGION TONIGHT/TUESDAY. MODEL GUIDANCE IS ALSO IN REASONABLE AGREEMENT IN A DRIER POCKET OF LOW LEVEL AIR ADVECTING NORTHWARD LATER TONIGHT AS THIS RIDGE AMPLIFIES...EFFECTIVELY SUPPRESSING ELEVATED CONVECTION. THUS...WILL KEEP FORECAST DRY TONIGHT. TUESDAY SHAPING UP TO BE ANOTHER DAY OF RECORD BREAKING WARMTH WITH DEEPER MIXING THAN MONDAY...THAT SHOULD SUPPORT HIGHS IN THE LOWER 80S MOST LOCATIONS. THIS DEEPER MIXING AND SLIGHTLY DRIER LOW LEVEL AIR SHOULD LIMIT DIURNAL INSTABILITY...AND WITH LARGE SCALE RIDGE IN PLACE...WILL KEEP REMAINDER OF SHORT TERM DRY. LONG TERM... / WEDNESDAY THROUGH SUNDAY / TREND IN MODEL GUIDANCE HAS BEEN TO SLOW THE EASTERN PROGRESSION OF A SOUTHERN PLAINS CUT-OFF UPPER LOW LATE THIS WEEK INTO SATURDAY. THIS IS NOT SURPRISING GIVEN THE NATURE OF CUT-OFFS AND EXPECTED AMPLIFICATION OF A HIGHLY ANOMALOUS EASTERN CONUS UPPER RIDGE. AS A RESULT OPTED TO BUY INTO THIS SLOWER SOLUTION WITH THIS DEEP TROPOSPHERIC CIRCULATION NOW PROGGED TO DRIFT TO THE MID MS VALLEY BY FRIDAY...AND THE OH VALLEY BY SATURDAY. RAISED HIGHS SEVERAL DEGREES...ESPECIALLY THURSDAY AND FRIDAY GIVEN THE SLOWER SOLUTION. A COOL DOWN IN STILL IN THE WORKS FRIDAY INTO THIS WEEKEND PER HEIGHT FALLS AND INCREASING CLOUDS/RAIN?...STILL LIKELY REMAINING AROUND 10 DEGREES OR SO ABOVE NORMAL BY THIS WEEKEND (COMPARED TO EXPECTED RECORD HIGH TEMPS AROUND 30 DEGREES ABOVE NORMAL TO START THE PERIOD). SYSTEM WILL MATURE AND FILL A BIT WITH EWD DRIFT AS IT COLLIDES WITH THE RIDGE...GETTING ITS KICK FROM ANOTHER LONGWAVE TROUGH PROGGED TO DIG TOWARDS THE WEST COAST. GIVEN THIS EXPECT FORCING TO WEAKEN A BIT AS IT FINALLY MAKES ITS WAY INTO THE OH VALLEY AND SRN GREAT LAKES. HOWEVER...THERE STILL SHOULD BE A MORE ORGANIZED BAND OF SHOWERS TO ACCOMPANY THE WEAKENING LOW LEVEL BAROCLINIC ZONE/OCCLUDED FRONT...WITH A MODEL CONSENSUS FAVORING THE FRIDAY-FRIDAY NIGHT PERIOD FOR MEASURABLE RAINFALL LOCALLY. RAINFALL AMOUNTS ARE NOT LOOKING OVERLY IMPRESSIVE ALTHOUGH SOME LOCALIZED HEAVIER RAIN APPEARS POSSIBLE GIVEN SUFFICIENT MOISTURE/WEAK INSTABILITY. CHANCES FOR SHOWERS LINGER INTO SATURDAY AS THE UPPER LOW AND ASSOCIATED COLD POOL ALOFT SHIFTS INTO REGION. OVERALL... CHANGES TO POPS/WX WERE TO REMOVE LOWER CHC POPS WEDNESDAY NIGHT AND LOWER THURSDAY POPS TO SLIGHT CHC. ONLY MINOR TWEAKS OTHERWISE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...MARSILI LONG TERM...STEINWEDEL AVIATION...BENTLEY/FISHER UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
240 PM MDT MON MAR 19 2012 .UPDATE... ISSUED AT 210 PM MDT MON MAR 19 2012 ADDING DIURNAL ISOLATED T AND -SHRA TO MY ERN ZONES BASED ON LATEST VIS SAT IMAGERY CONFIRMING SPC RUC INSTABILITY TRENDS AND ALSO SUPPORTED BY THE HRRR. THE ACTIVITY WILL MOVE TO THE NORTH THIS AFTERNOON AND SHOULD DIMINISH BY EARLY EVENING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 1259 PM MDT MON MAR 19 2012 MAIN CHANGE OVER THE PREVIOUS FCST WAS TO ADD LOW CHANCE POPS ACROSS THE COLORADO AND NEBRASKA ZONES FOR LATER THIS EVENING AND OVERNIGHT TONIGHT. THE REASONING IS BASED MUCH ON THE PROGGED DEVELOPMENT OF MID-LVL FRONT-G COUPLED WITH THE APPROACHING COLD FRONT AND ELEVATED INSTABILITY. SNDG PROFILES SUGGEST SHRA/FZRA FOR THESE ZONES GIVEN THE LACK OF ICE BEING INTRODUCED IN THE COLUMN. THE NARROW BAND OF PRECIP SHOULD END NORTH TO SOUTH BY MID-MORNING TOMORROW. WIND-WISE THE CURRENT LIGHT AND VAR WINDS WILL VEER TO NORTHERLY BEHIND THE FRONT GUSTING 20 TO 25 KTS AND ARE NOT EXPECT TO REACH ADVISORY CRITERIA. HIGH TEMPS TOMORROW WILL BE COOLER THAN TODAY BEHIND THE FRONT ALONG WITH NORTH WINDS AT 15 TO 25 MPH. NO PRECIP CHANCES WERE INTRODUCED AT THIS TIME. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 238 PM MDT MON MAR 19 2012 TUESDAY NIGHT THROUGH THURSDAY...FORECAST CONCERN CONTINUES TO FOCUS ON UPPER LOW AND HOW THE TRACK/TIMING WILL AFFECT TEMPS AND PRECIP OVER OUR CWA. CLOSED LOW IS STILL EXPECTED TO DEVELOP OVER TEXAS BY WEDNESDAY MORNING ON SOUTHERN FLANK OF LARGE SCALE TROUGH CURRENTLY DRAPED ACROSS THE INTER-MOUNTAIN WEST. LATEST MODELS HAVE COME INTO BETTER AGREEMENT ON GENERAL TRACK OF UPPER LOW ACROSS THE TEXAS PANHANDLE TOWARDS THE OK/KS BORDER BY WEDNESDAY NIGHT. THIS PUTS OUR CWA IN A FAVORABLE POSITION FOR PRECIP AS A BAND OF PRECIP FORMS ON THE NW QUAD OF THE H5/H7 LOW AND PUSHES NORTH TOWARDS NW KS. OVERALL TREND HAS BEEN TO SPEED UP THE ARRIVAL OF PRECIP...SO I ADDED 20/30 POPS TUESDAY NIGHT AFTER 06Z. PRECIP TYPE SHOULD REMAIN ALL RAIN TUESDAY NIGHT...THOUGH A RAIN/SNOW MIX COULDNT BE RULED OUT BEFORE SUNRISE. BETTER CHANCES OVERSPREAD THE CWA WEDNESDAY AND WEDNESDAY NIGHT AS UPPER LOW SHIFT NORTH. I BUMPED POPS ACROSS SE PART OF THE CWA TO LIKELY CATEGORY FOR THESE PERIODS WHERE THERE IS GOOD OVERLAP BETWEEN MODEL QPF AND PROJECTED LIFT/MOISTURE. THERE IS LESS CERTAINTY REGARDING THE EVOLUTION OF THE UPPER LOW AND POSITION OF DRY SLOT BY THURSDAY. WITH THIS IN MIND...I ADJUSTED POPS THURSDAY TO ACCOUNT FOR CURRENT PROJECTED DRY SLOT POSITION IN THE EAST BY LIMITING POPS TO SLIGHT CATEGORY. I WAS NOT COMFORTABLE PULLING OR RAISING POPS BEYOND THE 20/40 RANGE THURSDAY CONSIDERING THE POOR PERFORMANCE OF GUIDANCE ON CLOSED SYSTEMS FOR OUR AREA. I AM NOT CONFIDENT IN HIGH TEMPS WEDNESDAY OR THURSDAY...WHICH WILL BE DEPENDENT ON LOCATION OF CLOUD COVER AND PRECIP BOTH DAYS. OVERALL I TRENDED TEMPS DOWN A LITTLE...BUT KEPT THE CWA GENERALLY IN THE MID 50S TO LOW 60S. IT SHOULD BE COOLER FOR LOCATIONS WITH PRECIP/THICK CLOUD COVER. FRIDAY THROUGH MONDAY...OMEGA BLOCK TYPE PATTERN ESTABLISHES ITSELF BY THIS WEEKEND WITH H5 RIDGE ACROSS THE CENTRAL CONUS. GFS AND GEFS ARE MUCH MORE PROGRESSIVE WITH THE RIDGE...WHICH IS UNREALISTIC CONSIDERING THE WAY THESE PATTERN USUALLY EVOLVE OVER THE CENTRAL US. GUIDANCE IN THE PAST TENDS TO BE TOO QUICK TO MOVE UPSTREAM CLOSED LOWS EASTWARD...WHICH IS LIKELY THE CASE WITH THE GFS. ECMWF HOLDS ONTO THE STRONG RIDGE THROUGH THE MIDDLE OF NEXT WEEK. THE RESULT OF A SLOWER SOLUTION WILL BE WARMER TEMPERATURES AND DRY CONDITIONS THROUGH THESE PERIODS. I TRENDED TEMPS UP SAT/SUN/MON WITH HIGHS IN THE MID-UPPER 70S...NEAR 80F ACROSS THE AREA. THIS MAY STILL BE TOO COOL...WITH A STRETCH OF VERY WARM TEMPERATURES AND DRY CONDITIONS SIMILAR TO WHAT WE HAD LATE LAST WEEK AND THIS PAST WEEKEND CERTAINLY POSSIBLE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1127 AM MDT MON MAR 19 2012 VFR CIGS AND VIS ARE EXPECTED THROUGH THE PERIOD AT BOTH MCK AND GLD. CIGS SHOULD LOWER TONIGHT ASSOCIATED WITH THE PASSAGE OF A COLD FRONT BUT STILL REMAIN ABOVE 3000 FT. UNTIL THE FRONT ARRIVES LATER TONIGHT THE SFC WINDS SHOULD BE LIGHT AND VARIABLE. AS THE FRONT ARRIVES THE WINDS WILL VEER TO THE NORTHWEST WITH GUSTS AROUND 20-25 KTS. AS FOR PRECIP CHANCES...THERE IS A LOW CHANCE THERE MAY BE SOME VERY LIGHT SNOW OR A MIX OF RAIN SNOW AT KGLD LATER TONIGHT. AT THIS TIME I DID NOT INTRODUCE AND PRECIP GIVEN MY LOW CONFIDENCE. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...05 SHORT TERM...05 LONG TERM....DR AVIATION...05
AREA FORECAST DISCUSSION
NWS GOODLAND KS
215 PM MDT MON MAR 19 2012 .UPDATE... ISSUED AT 210 PM MDT MON MAR 19 2012 ADDING DIURNAL ISOLATED T AND -SHRA TO MY ERN ZONES BASED ON LATEST VIS SAT IMAGERY CONFIRMING SPC RUC INSTABILITY TRENDS AND ALSO SUPPORTED BY THE HRRR. THE ACTIVITY WILL MOVE TO THE NORTH THIS AFTERNOON AND SHOULD DIMINISH BY EARLY EVENING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 1259 PM MDT MON MAR 19 2012 MAIN CHANGE OVER THE PREVIOUS FCST WAS TO ADD LOW CHANCE POPS ACROSS THE COLORADO AND NEBRASKA ZONES FOR LATER THIS EVENING AND OVERNIGHT TONIGHT. THE REASONING IS BASED MUCH ON THE PROGGED DEVELOPMENT OF MID-LVL FRONT-G COUPLED WITH THE APPROACHING COLD FRONT AND ELEVATED INSTABILITY. SNDG PROFILES SUGGEST SHRA/FZRA FOR THESE ZONES GIVEN THE LACK OF ICE BEING INTRODUCED IN THE COLUMN. THE NARROW BAND OF PRECIP SHOULD END NORTH TO SOUTH BY MID-MORNING TOMORROW. WIND-WISE THE CURRENT LIGHT AND VAR WINDS WILL VEER TO NORTHERLY BEHIND THE FRONT GUSTING 20 TO 25 KTS AND ARE NOT EXPECT TO REACH ADVISORY CRITERIA. HIGH TEMPS TOMORROW WILL BE COOLER THAN TODAY BEHIND THE FRONT ALONG WITH NORTH WINDS AT 15 TO 25 MPH. NO PRECIP CHANCES WERE INTRODUCED AT THIS TIME. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 103 AM MDT MON MAR 19 2012 UPPER LOW AT THE BEGINNING OF THE PERIOD WILL BE MEANDERING AROUND THE SOUTHERN PLAINS. ALTHOUGH MODELS SHOW IT TAKING A BIT OF A NORTHERN JOG ON THURSDAY THIS LOOKS VERY SUSPICIOUS...AND MODELS HAVE BEEN TERRIBLE WITH UPPER LOWS RECENTLY. NONETHELESS...WILL THROW IN SOME SLIGHT CHANCE POPS FOR THE TIME BEING. AFTER THE LOW GETS OUT OF HERE...UPPER RIDGE WILL BUILD FROM THE WEST AND DOMINATE THE REMAINDER OF THE PERIOD WITH WARM AND DRY CONDITIONS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1127 AM MDT MON MAR 19 2012 VFR CIGS AND VIS ARE EXPECTED THROUGH THE PERIOD AT BOTH MCK AND GLD. CIGS SHOULD LOWER TONIGHT ASSOCIATED WITH THE PASSAGE OF A COLD FRONT BUT STILL REMAIN ABOVE 3000 FT. UNTIL THE FRONT ARRIVES LATER TONIGHT THE SFC WINDS SHOULD BE LIGHT AND VARIABLE. AS THE FRONT ARRIVES THE WINDS WILL VEER TO THE NORTHWEST WITH GUSTS AROUND 20-25 KTS. AS FOR PRECIP CHANCES...THERE IS A LOW CHANCE THERE MAY BE SOME VERY LIGHT SNOW OR A MIX OF RAIN SNOW AT KGLD LATER TONIGHT. AT THIS TIME I DID NOT INTRODUCE AND PRECIP GIVEN MY LOW CONFIDENCE. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...05 SHORT TERM...05 LONG TERM....024 AVIATION...05
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
600 PM EDT MON MAR 19 2012 .SYNOPSIS... INCREASING HUMIDITY MAY GENERATE ISOLATED THUNDERSTORMS THIS EVENING ACROSS EAST CENTRAL OHIO AND NEAR THE APPALACHIAN MOUNTAINS. PATCHY FOG CAN DEVELOP TOWARD MORNING. STRENGTHENING HIGH PRESSURE WILL CONTINUE WARM TEMPERATURES AND GENERALLY DRY CONDITIONS INTO FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... RECENT RADAR DATA SHOWS ISOLATED SLOW MOVING THUNDERSTORMS ACROSS EAST CENTRAL OHIO, AND ANOTHER BATCH OVER THE NORTHERN PENNSYLVANIA MOUNTAINS. PER RECENT RADAR MOVEMENT AND HRRR MODEL OUTPUT, EXPECT THE OHIO STORMS TO SPREAD JUST EAST OF THE I-77 CORRIDOR BEFORE DISSIPATING AFTER DARK AS NOCTURNAL COOLING BEGINS. LIKEWISE THE STORMS JUST NORTHEAST OF JEFFERSON COUNTY PA SHOULD DISSIPATE THEN ALSO. THE REST OF THE UPPER OHIO VALLEY SHOULD REMAIN DRY. HAVE INTRODUCED PATCHY RIVER VALLEY FOG LATE TONIGHT AND EARLY TUESDAY MORNING AS SUGGESTED BY RECENT NAM MODEL PROFILES AND GFS AND NAM MOS. UPPER RIDGE AND SURFACE HIGH PRESSURE WILL THEN DOMINATE TUESDAY WITH VERY WARM TEMPERATURES. WITH DAYTIME HEATING AND SOME INSTABILITY A STRAY AFTERNOON THUNDERSHOWER IS POSSIBLE BUT OVERALL CONDITIONS WILL BE DRY. FORECASTED SPECIFIC TEMPERATURES USING BLEND OF NAM MOS, GFS MOS AND LAMP. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... RECENT SREF MODEL OUTPUT CONTINUES TO SHOW UPPER RIDGE WILL PROVIDE JUNE-LIKE TEMPERATURES AND MAINLY DRY CONDITIONS, WITH NO MORE THAN AN ISOLATED LATE AFTERNOON THUNDERSHOWER POSSIBLE. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... OCCLUDED LOW PRESSURE SYSTEM WILL GRADUALLY TRACK EAST FROM THE MS VALLEY ACROSS THE OHIO VALLEY DURING THE WEEKEND. A BACK DOOR COLD FRONT PROGGED TO SAG SOUTHWARD AHEAD OF THE SYSTEM COULD BRING WIDELY SCATTERED SHOWERS ON FRIDAY...BUT A GREATER COVERAGE OF SHOWERS AND STORMS CAN BE EXPECTED SATURDAY INTO SUNDAY WITH THE EASTWARD MOVING LOW. A SURFACE RIDGE BUILDING IN BEHIND THE SYSTEM SHOULD BRING DRY CONDITIONS ON MONDAY. HIGH TEMPERATURES WILL COOL DOWN INTO THE MID 50S TO MID 60S BY SUNDAY AND MONDAY...BUT OVERALL TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... ISOLATED SHOWERS AND STORMS CAN BE EXPECTED OVER EAST CENTRAL OHIO INCLUDING KZZV THROUGH AROUND 23Z. MVFR CEILINGS WILL LIKELY PERSIST OVER NORTHWEST PA INCLUDING KDUJ AND KFKL INTO TONIGHT...WITH PREDOMINATELY VFR ELSEWHERE THROUGH EARLY TONIGHT. LOW LEVEL MOISTURE WILL REMAIN ACROSS THE REGION...WITH AREAS OF MVFR CEILINGS AND FOG LIKELY REFORMING AFTER 06Z TONIGHT...AND IFR RESTRICTIONS REDEVELOPING AT KDUJ AND KFKL. IMPROVEMENT TO GENERALLY VFR IS FORECAST AFTER 15Z TUESDAY. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... AN UPPER LEVEL RIDGE WILL PROVIDE GENERALLY VFR CONDITIONS THROUGH FRIDAY. A LOW PRESSURE SYSTEM MOVING EAST FROM THE MS VALLEY WILL BRING SCATTERED SHOWERS AND STORMS AND THE POTENTIAL FOR RESTRICTIONS FRIDAY NIGHT INTO SATURDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
551 PM EDT MON MAR 19 2012 .SYNOPSIS... SURFACE HIGH PRESSURE REMAINS ANCHORED OFF THE COAST THROUGH LATE THIS WEEK. A SERIES OF WEAK SHORTWAVES WILL CREATE THE POTENTIAL FOR AFTERNOON SHOWERS AND THUNDERSTORMS TUESDAY THROUGH FRIDAY. A LOW PRESSURE SYSTEM WILL IMPACT THE REGION THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... QUICK UPDATE TO GOING FORECAST TO REFLECT CURRENT ORIENTATION OF POPS. NEW 18Z NAM AND LAST FEW RUNS OF HRRR HAVE DONE A GOOD JOB WITH HANDLING WEAK SHORTWAVE TO OUR NORTH, NICELY DEPICTED ON IR/WV SAT IMAGERY. DRIER AIR PUSHING IN FROM THE WEST HAS ALLOWED FOR WANING INSTABILITY AND A REASONABLY STRONG CAPPED ENVIRONMENT...WHICH SHORT RANGE MODELS ALLOW TO PRESIST THROUGH THE EVENING. ACCORDINGLY...HAVE SHUNTED ISO TSRA WORDING OUT OF THE PIEDMONT INTO EASTERN THIRD OF THE CWA...WITH ANY ACTIVITY WANING QUICKLY AFTER SUNSET. OFFSHORE LOW PRESSURE CIRCULATION LOCATED ABOUT 100-150 MILES EAST-SOUTHEAST OF THE VA/NC BORDER IS PROGGED TO MOVE UP THE MID ATLANTIC COAST OVERNIGHT. THIS WILL BRING CLOUDS OVER THE DELMARVA OVERNIGHT AND SPREAD LIGHT SHOWERS ALONG THE COAST BY TUESDAY MORNING. FOG WILL DEVELOP AGAIN TONIGHT ACROSS THE REGION BUT SHOULD NOT FORM UNTIL AFTER MIDNIGHT. VARIABLE VISIBILITIES ARE EXPECTED THROUGHOUT THE AREA...HOWEVER LOCALLY DENSE FOG IS POSSIBLE IN LOCATIONS THAT EXPERIENCE FULL CLEARING THIS EVENING AND IN RURAL AREAS AS WELL. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... FOG IS EXPECTED TO DISSIPATE SHORTLY AFTER SUNRISE AND BY MID MORNING (9-10 AM) FOR AREAS THAT EXPERIENCE LOCALLY DENSE FOG. YET ANOTHER WEAK SHORTWAVE WILL DROP DOWN FROM THE EASTERN GREAT LAKES REGION TUESDAY AND PROVIDE ENOUGH ENERGY AND LIFT FOR SHOWER DEVELOPMENT. AN AREA OF POSITIVE VORTICITY ADVECTION ASSOCIATED WITH THE SHORTWAVE WILL SLIDE INTO THE DELMARVA REGION FROM THE NORTH BY MID MORNING AND INTERACT WITH THE OFFSHORE LOW. THIS FEATURE WILL BECOME A FOCUSING MECHANISM FOR THUNDERSTORM ACTIVITY FROM THE DELMARVA COAST...DOWN THROUGH THE NE NORTH CAROLINA COAST... AND TILTING TOWARD INTERIOR VA DURING THE AFTERNOON. THE EASTERN PIEDMONT WILL BE CO-LOCATED WITH AN AREA OF CONVERGENCE ALSO IN THE AFTERNOON...CONTINUING SHOWER AND THUNDERSTORM CHANCES IN THIS REGION. TUESDAY NIGHT AND WEDNESDAY NIGHT WILL LIKELY BE SIMILAR TO MONDAY NIGHT AS FOG RE-DEVELOPS LATE AND PERSISTS THROUGH EARLY WEDNESDAY MORNING. WEDNESDAY AND THURSDAY BRING LITTLE CHANGE TO THE CURRENT WEATHER PATTERN WITH SURFACE HIGH PRESSURE ANCHORED OFFSHORE AND WEAK SHORTWAVES PROVIDING JUST ENOUGH INSTABILITY FOR SHOWER AND THUNDERSTORM CHANCES EACH AFTERNOON. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... H5 RIDGE WILL BE POSITIONED OVER THE SE U.S. THURSDAY NIGHT/FRIDAY. FOR THE MOST PART...THINK WX WILL BE DRY BUT MODELS DO HINT AT AN ISOLATED AFTN SHWR/TSTORM FOR FRI SO WILL CARRY 20% POP. LOWS THURS NIGHT IN THE 50S. HIGHS FRIDAY FROM THE MID/UPR 60S AT THE COAST TO THE LOW 80S ALONG AND WEST OF THE I-95 CORRIDOR. MODELS CONTINUE TO SHOW THE UPR LOW OUT WEST SLOWLY PUSHING EASTWARD THROUGH THE WEEK AND EVENTUALLY IMPACTING THE MID-ATLANTIC REGION THIS COMING WEEKEND. MOISTURE ASSOCIATED WITH THIS SYSTEM SLOWLY SPREADS EAST AND INTO THE FA LATE FRIDAY NIGHT AND SATURDAY. STILL SOME DIFFERENCES ON THE TRACK OF THE ACTUAL UPR LOW...SO FOR NOW WILL CARRY CHC POPS FROM SATURDAY THROUGH SUNDAY. THE UPR LOW SHOULD BEGIN TO PULL AWAY FROM OUR AREA SUNDAY NIGHT BUT AGAIN THERE ARE TIMING DIFFERENCE IN THE MODELS WHICH COULD DELAY THE END TIME OF PRECIP. FOR NOW...WILL MAINTAIN SLIGHT CHC POPS SUNDAY NIGHT AND IF PREVIOUS RUNS CONTINUE TO SLOW THE UPR LOW DOWN THEN WILL ADJUST POPS UP ACCORDINGLY. DRY WX SHOULD RETURN TO START NEXT WEEK. STILL MILD SATURDAY WITH HIGHS IN THE 70S EXCEPT M-U60S COASTAL AREAS. A LITTLE COOLER BUT STILL ABOVE NORMAL SUNDAY/MONDAY WITH HIGHS AROUND 70 EXCEPT 60-65 COASTAL AREAS. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THIS AFTERNOON INTO THIS EVENING FOR ALL TAF SITES WITH LIGHT WINDS. LATER TONIGHT...AM EXPECTING AREAS OF FOG AND/OR LOW CLOUDS TO AGAIN BE POSSIBLE. WORST OF THE CONDITIONS SHOULD BE BETWEEN 08Z-13Z TUES. SIMILAR SETUP TUE AFTN THROUGH WED MORNING...WITH VFR CONDS AFTER MORNING FOG/LOW CLOUDS BURN OFF...AND BETTER CHANCE OF WIDELY SCATTERED MAINLY LATE AFTN AND EVENING TSTMS. A BIT MORE SOUTHERLY FLOW WED NIGHT-FRI...SO DIURNAL PATTERN OF MORNING LOW CLOUDS/FOG WILL TEND TO DIMINISH. && .MARINE... OVERALL WILL BE A BENIGN PERIOD FOR THE WATERS THROUGH FRI...A BROAD SFC HIGH WILL REMAIN ANCHORED OFF THE MID ATLC COAST... KEEPING ANY SIGNIFICANT LOW PRESSURE SYSTEMS WELL OFF TO OUR WEST. FOR REST OF TODAY AND TUES THERE WILL BE A VERY WEAK PRESSURE GRADIENT...AND ONSHORE FLOW SHOULD DOMINATE WITH WINDS GENLY FROM THE NE IN THE AM HRS TURNING MORE E FOR THE AFTN/EVENING. FAIRLY LIGHT WIND SPEEDS...AVERAGING OUT AT 5-10 KT...WITH A SLIGHT INCREASE POSSIBLE DURING THE AFTN AND EVENINGS. SEAS 2-3 FT AND WAVES IN THE BAY 1-2 FT. SOME FOG WILL CONTINUE TO BE POSSIBLE MAINLY DURING THE AM HRS TUES AND WED. WINDS BECOME SW BY WED AROUND 10KT...THEN SW THURS/FRI BETWEEN 10-15 KT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...TMG/BMD NEAR TERM...MAM/BMD SHORT TERM...BMD LONG TERM...JDM AVIATION...JDM MARINE...JDM
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
657 PM EDT MON MAR 19 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 438 PM EDT MON MAR 19 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A VERY AMPLIFIED PATTERN WITH A DEEP MID/UPPER LEVEL TROUGH OVER THE GREAT BASIN INTO THE ROCKIES AND A RIDGE FROM THE GULF INTO THE CENTRAL GREAT LAKES AND NRN ONTARIO RESULTING IN SSW FLOW FROM THE SRN PLAINS TO THE UPPER MS VALLEY AND WRN GREAT LAKES. CAPPING EVIDENT ON MORNING SOUNDINGS AND FCST SOUNDINGS EARLY THIS AFTERNOON HAS WEAKENED AS A WEAK SHORTWAVE TROUGH OVER SRN WI LIFTS TO THE NORTH. THE SHRTWV COMBINED WITH MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE SUPPORTED AN AREA OF SHOWERS OVER SE WI AND MORE ISOLD SHRA/TSRA OVER NRN WI. ANOTHER AREA OF SHRA/TSRA WAS LOCATED OVER NE IA INTO SE MN. OTHERWISE...PLENTY OF SUNSHINE AND AFTERNOON MIXING HAS AGAIN PUSHED TEMPS AGAIN TO RECORD HIGHS INTO THE MID AND UPPER 70S. AS THE WI SHRTWV LIFTS TO THE NORTH EXPECT THE ISOLD CONVECTION OVER NRN WI TO ALSO MOVE INTO SRN UPPER MI LATE THIS AFTERNOON AND EVENING. WITH COOLING LATER THIS EVENING...EXPECT THE PCPN TO DIMINISH. STRONGER SHORTWAVES LIFTING OUT OF THE NRN PLAINS INTO SASK AND MANITOBA ARE EXPECTED TO GRADUALLY FLATTEN THE RIDGE AND ALLOW THE FRONT OVER THE ERN DAKOTAS TO SHIFT TO THE EAST. HOWEVER THE STRONGER LARGE SCALE DYNAMICS WITH UPPER LEVEL DIV ASSOCIATED WITH THE UPPER JET MOVING INTO N ONTARIO WILL REMAIN WILL REMAIN NORTHWEST OF LAKE SUPERIOR. WITH CONTINUED SSW MID LEVEL FLOW AND THE VERY MOIST AND UNSTABLE AIRMASS OVER THE REGION...WEAK SHORTWAVES ARE STILL EXPECTED TO TRIGGER SOME SCT/ISOLD SHRA/TSRA INTO MAINLY THE WEST HALF OF UPPER MI. AS IS TYPICAL WITH WARM SEASON CONVECTION...THERE IS CONSIDERABLE UNCERTAINTY WITH THE TIMING/POSITION OF ANY SHRA/TSRA ASSOCIATED WITH THE WEAK DISTURBANCES. SO...THE FCST CONTINUES TO CARRY CHANCE POPS LOWER END CHANCE POPS THROUGH THE PERIOD OVER THE WEST. TEMPS WILL REMAIN IN RECORD TERRITORY FOR HIGH OVERNIGHT MINS AND MAX READINGS TUESDAY WITH LOWS IN THE 50S AND HIGHS REACHING THE MID 70S. WITH A FEW MORE CLOUDS OVER THE AREA...TEMPS MAY BE SLIGHTLY COOLER THAN TODAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 438 PM EDT MON MAR 19 2012 TUESDAY NIGHT THROUGH THURSDAY... OUR STAGNANT 500MB WEATHER PATTERN OF LATE...WITH THE HIGH AMPLITUDE 500MB RIDGE OVER THE EASTERN HALF OF THE NATION WILL BECOME SUPPRESSED...BUT STILL OVERHEAD THROUGH THURSDAY NIGHT. TAKING A LOOK CLOSER TO THE SFC...THE WEAKENING COLD FRONT STRETCHING FROM THE MAIN SFC LOWS ACROSS FAR NE MANITOBA AND IA WILL SHIFT OVER THE EASTERN HALF OF THE CWA BY 21-00Z WEDNESDAY AFTERNOON...WHILE CONTINUING TO WEAKEN/WASH OUT TO OUR EAST WEDNESDAY NIGHT WITH STRONG HIGH PRESSURE BUILDING IN ACROSS LAKE SUPERIOR. THE ENTIRE SYSTEM LOOKS TO HAVE SLOWED DOWN A BIT MORE. IT WILL HAVE ASSISTANCE FROM THE EXITING 300MB JET...BUT THIS WILL MAINLY BE ACROSS W TO NORTH CENTRAL UPPER MI...AND LAKE SUPERIOR. DID NOT GO WITH HIGH POPS YET...DUE TO THE LOW PROBABILITY AND DIMINISHED AMOUNTS OF PRECIP EXPECTED. BEHIND THE FRONT...WHILE A HUGE COOL DOWN IS NOT EXPECTED...850MB TEMPS WILL STILL FALL FROM AROUND 11C TO NEAR 8C BY THURSDAY AFTERNOON ON LIGHT WINDS. THURSDAY NIGHT THROUGH MONDAY... THE 500MB LOW...CURRENTLY ORGANIZING ACROSS THE 4-CORNERS REGION TODAY WILL BE OVER N TX AT 00Z THURSDAY. EXPECT THIS CUT OFF LOW TO EJECT NORTHWARD AFTER 00Z THURSDAY...PUSHING ACROSS E KS FRIDAY MORNING...AND MO BY FRIDAY AFTERNOON. JUST HOW MUCH OF AN INFLUENCE THIS TRACK HAS ON OUR WEATHER IS STILL IN QUESTION...AS THE 500MB LOW SLIPS EASTWARD TO THE LOWER OH VALLEY SATURDAY /AND SFC LOW MOVES AS FAR NORTH AS SCENTRAL WI AT 00Z SATURDAY/...BEFORE FURTHER EXITING EASTWARD AND WEAKENING SUNDAY ACROSS THE CAROLINAS...WITH A REBOUNDING RIDGE BUILDING ACROSS THE PLAINS AND UPPER GREAT LAKES. STILL HAVE A CHANCE OF RAIN FRIDAY MORNING THROUGH THE DAY SATURDAY...BUT WILL WAIT TO SEE ON MUCH NEEDED AMOUNTS OF MOISTURE. EVEN WITH THE RIDGE BUILDING BACK ACROSS THE CWA...NE WINDS WILL PULL COOLER AIR DOWN FROM ONTARIO. THE 19/00Z RUN OF THE ECMWF EVEN INDICATES 850MB TEMPS OVER THE TIP OF THE KEWEENAW AROUND 0C AT 06Z SUNDAY. HOWEVER...THE WARMER 19/06Z RUN OF THE GFS IS STILL AROUND 4C. EITHER WAY...LOOK FOR WAA ON WEAK S-SW WINDS AGAIN BY MONDAY AFTERNOON. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 656 PM EDT MON MAR 19 2012 CIGS/VSBYS SHOULD REMAIN VFR THROUGH THE PERIOD AT CMX AND IWD. S-SE WINDS OFF OF LAKE MICHIGAN TONIGHT MAY CAUSE VSBYS AT SAW TO DROP TO MVFR OVERNIGHT AND PUSHED IT BACK TO LATE TONIGHT. CONFIDENCE IS FAIRLY LOW THOUGH AS PAST SEVERAL NIGHTS HAVE SEEN NO FOG. USUALLY WHEN THE WIND IS SOUTH AND THERE IS FOG IN LAKE MICHIGAN...CIGS AND VIS COME DOWN AT SAW. AS DAYTIME HEATING SUBSIDES AND MIXING DIMINISHES...EXPECT LLWS TO DEVELOP AGAIN TONIGHT AT ALL SITES. DID PUT IN CHANCE OF SHOWERS TUE AFTERNOON OVER IWD AS FRONTAL BAND GETS CLOSER TO THAT AREA. FURTHER EAST...CONFIDENCE IN SEEING SHOWERS IS LOWER AND DID NOT INCLUDE AT THIS TIME. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 438 PM EDT MON MAR 19 2012 SOUTHERLY FLOW WILL CONTINUE THROUGH WEDNESDAY AHEAD OF STRONG LOW PRESSURE OVER THE PLAINS. DUE TO THE SUMMER TYPE NATURE OF THE SYSTEM...WINDS AS THE SURFACE OF THE LAKE REMAIN FAIRLY WEAK DUE TO THE MARINE LAYER...ALTHOUGH WINDS ABOVE THE MARINE LAYER ARE MUCH STRONGER. IN ADDITION...DESPITE THE SOUTHERLY SYNOPTIC FLOW...WINDS ACROSS THE WEST EAST OR NORTHEASTERLY AS IS TYPICAL DURING THE SPRING WITH LOW PRESSURE TO THE WEST. EXPECT WINDS TO TURN WESTERLY WED BEHIND THE COLD FRONT...THEN ONCE AGAIN SOUTHERLY BY THE WEEKEND AS ANOTHER LOW PRESSURE DEVELOPS OVER THE PLAINS. OTHER THAN TODAY...EXPECT WINDS TO REMAIN BELOW 30 KT THROUGH THE FORECAST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 PM EDT MON MAR 19 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 438 PM EDT MON MAR 19 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A VERY AMPLIFIED PATTERN WITH A DEEP MID/UPPER LEVEL TROUGH OVER THE GREAT BASIN INTO THE ROCKIES AND A RIDGE FROM THE GULF INTO THE CENTRAL GREAT LAKES AND NRN ONTARIO RESULTING IN SSW FLOW FROM THE SRN PLAINS TO THE UPPER MS VALLEY AND WRN GREAT LAKES. CAPPING EVIDENT ON MORNING SOUNDINGS AND FCST SOUNDINGS EARLY THIS AFTERNOON HAS WEAKENED AS A WEAK SHORTWAVE TROUGH OVER SRN WI LIFTS TO THE NORTH. THE SHRTWV COMBINED WITH MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE SUPPORTED AN AREA OF SHOWERS OVER SE WI AND MORE ISOLD SHRA/TSRA OVER NRN WI. ANOTHER AREA OF SHRA/TSRA WAS LOCATED OVER NE IA INTO SE MN. OTHERWISE...PLENTY OF SUNSHINE AND AFTERNOON MIXING HAS AGAIN PUSHED TEMPS AGAIN TO RECORD HIGHS INTO THE MID AND UPPER 70S. AS THE WI SHRTWV LIFTS TO THE NORTH EXPECT THE ISOLD CONVECTION OVER NRN WI TO ALSO MOVE INTO SRN UPPER MI LATE THIS AFTERNOON AND EVENING. WITH COOLING LATER THIS EVENING...EXPECT THE PCPN TO DIMINISH. STRONGER SHORTWAVES LIFTING OUT OF THE NRN PLAINS INTO SASK AND MANITOBA ARE EXPECTED TO GRADUALLY FLATTEN THE RIDGE AND ALLOW THE FRONT OVER THE ERN DAKOTAS TO SHIFT TO THE EAST. HOWEVER THE STRONGER LARGE SCALE DYNAMICS WITH UPPER LEVEL DIV ASSOCIATED WITH THE UPPER JET MOVING INTO N ONTARIO WILL REMAIN WILL REMAIN NORTHWEST OF LAKE SUPERIOR. WITH CONTINUED SSW MID LEVEL FLOW AND THE VERY MOIST AND UNSTABLE AIRMASS OVER THE REGION...WEAK SHORTWAVES ARE STILL EXPECTED TO TRIGGER SOME SCT/ISOLD SHRA/TSRA INTO MAINLY THE WEST HALF OF UPPER MI. AS IS TYPICAL WITH WARM SEASON CONVECTION...THERE IS CONSIDERABLE UNCERTAINTY WITH THE TIMING/POSITION OF ANY SHRA/TSRA ASSOCIATED WITH THE WEAK DISTURBANCES. SO...THE FCST CONTINUES TO CARRY CHANCE POPS LOWER END CHANCE POPS THROUGH THE PERIOD OVER THE WEST. TEMPS WILL REMAIN IN RECORD TERRITORY FOR HIGH OVERNIGHT MINS AND MAX READINGS TUESDAY WITH LOWS IN THE 50S AND HIGHS REACHING THE MID 70S. WITH A FEW MORE CLOUDS OVER THE AREA...TEMPS MAY BE SLIGHTLY COOLER THAN TODAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 438 PM EDT MON MAR 19 2012 TUESDAY NIGHT THROUGH THURSDAY... OUR STAGNANT 500MB WEATHER PATTERN OF LATE...WITH THE HIGH AMPLITUDE 500MB RIDGE OVER THE EASTERN HALF OF THE NATION WILL BECOME SUPPRESSED...BUT STILL OVERHEAD THROUGH THURSDAY NIGHT. TAKING A LOOK CLOSER TO THE SFC...THE WEAKENING COLD FRONT STRETCHING FROM THE MAIN SFC LOWS ACROSS FAR NE MANITOBA AND IA WILL SHIFT OVER THE EASTERN HALF OF THE CWA BY 21-00Z WEDNESDAY AFTERNOON...WHILE CONTINUING TO WEAKEN/WASH OUT TO OUR EAST WEDNESDAY NIGHT WITH STRONG HIGH PRESSURE BUILDING IN ACROSS LAKE SUPERIOR. THE ENTIRE SYSTEM LOOKS TO HAVE SLOWED DOWN A BIT MORE. IT WILL HAVE ASSISTANCE FROM THE EXITING 300MB JET...BUT THIS WILL MAINLY BE ACROSS W TO NORTH CENTRAL UPPER MI...AND LAKE SUPERIOR. DID NOT GO WITH HIGH POPS YET...DUE TO THE LOW PROBABILITY AND DIMINISHED AMOUNTS OF PRECIP EXPECTED. BEHIND THE FRONT...WHILE A HUGE COOL DOWN IS NOT EXPECTED...850MB TEMPS WILL STILL FALL FROM AROUND 11C TO NEAR 8C BY THURSDAY AFTERNOON ON LIGHT WINDS. THURSDAY NIGHT THROUGH MONDAY... THE 500MB LOW...CURRENTLY ORGANIZING ACROSS THE 4-CORNERS REGION TODAY WILL BE OVER N TX AT 00Z THURSDAY. EXPECT THIS CUT OFF LOW TO EJECT NORTHWARD AFTER 00Z THURSDAY...PUSHING ACROSS E KS FRIDAY MORNING...AND MO BY FRIDAY AFTERNOON. JUST HOW MUCH OF AN INFLUENCE THIS TRACK HAS ON OUR WEATHER IS STILL IN QUESTION...AS THE 500MB LOW SLIPS EASTWARD TO THE LOWER OH VALLEY SATURDAY /AND SFC LOW MOVES AS FAR NORTH AS SCENTRAL WI AT 00Z SATURDAY/...BEFORE FURTHER EXITING EASTWARD AND WEAKENING SUNDAY ACROSS THE CAROLINAS...WITH A REBOUNDING RIDGE BUILDING ACROSS THE PLAINS AND UPPER GREAT LAKES. STILL HAVE A CHANCE OF RAIN FRIDAY MORNING THROUGH THE DAY SATURDAY...BUT WILL WAIT TO SEE ON MUCH NEEDED AMOUNTS OF MOISTURE. EVEN WITH THE RIDGE BUILDING BACK ACROSS THE CWA...NE WINDS WILL PULL COOLER AIR DOWN FROM ONTARIO. THE 19/00Z RUN OF THE ECMWF EVEN INDICATES 850MB TEMPS OVER THE TIP OF THE KEWEENAW AROUND 0C AT 06Z SUNDAY. HOWEVER...THE WARMER 19/06Z RUN OF THE GFS IS STILL AROUND 4C. EITHER WAY...LOOK FOR WAA ON WEAK S-SW WINDS AGAIN BY MONDAY AFTERNOON. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 130 PM EDT MON MAR 19 2012 A WEAK MID/UPPER LEVEL SHORTWAVE TROUGH WILL MOVE TOWARD THE AREA LATE THIS AFTERNOON INTO THIS EVENING. THERE MAY BE A PASSING SHOWER ACROSS THE WESTERN PART OF UPPER MICHIGAN BUT WIDESPREAD PCPN IS NOT EXPECTED AND CIGS/VSBYS SHOULD REMAIN VFR. S-SE WINDS OFF OF LAKE MICHIGAN TONIGHT MAY CAUSE VSBYS AT SAW TO DROP TO MVFR OVERNIGHT. OTHERWISE...ALL OTHER SITES WILL REMAIN VFR. GUSTY S-SE WINDS WILL CONTINUE AGAIN TODAY WITH GUSTS UP TO 30 KT POSSIBLE. AS DAYTIME HEATING SUBSIDES AND MIXING DIMINISHES...EXPECT LLWS TO DEVELOP AGAIN TONIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 438 PM EDT MON MAR 19 2012 SOUTHERLY FLOW WILL CONTINUE THROUGH WEDNESDAY AHEAD OF STRONG LOW PRESSURE OVER THE PLAINS. DUE TO THE SUMMER TYPE NATURE OF THE SYSTEM...WINDS AS THE SURFACE OF THE LAKE REMAIN FAIRLY WEAK DUE TO THE MARINE LAYER...ALTHOUGH WINDS ABOVE THE MARINE LAYER ARE MUCH STRONGER. IN ADDITION...DESPITE THE SOUTHERLY SYNOPTIC FLOW...WINDS ACROSS THE WEST EAST OR NORTHEASTERLY AS IS TYPICAL DURING THE SPRING WITH LOW PRESSURE TO THE WEST. EXPECT WINDS TO TURN WESTERLY WED BEHIND THE COLD FRONT...THEN ONCE AGAIN SOUTHERLY BY THE WEEKEND AS ANOTHER LOW PRESSURE DEVELOPS OVER THE PLAINS. OTHER THAN TODAY...EXPECT WINDS TO REMAIN BELOW 30 KT THROUGH THE FORECAST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...KF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1239 PM CDT MON MAR 19 2012 .AVIATION...18Z TAFS FOR KOMA...KLNK AND KOFK. SHOWERS WILL CONTINUE TO MOVE OVER THE TAF SITES FOR THE AFTERNOON. ALTHOUGH ISOLATED TSTMS ARE POSSIBLE...DID NOT MENTION THIS IN THE TAF BUT RATHER INCLUDED A CB MENTION WITH THE CLOUDS AS COVERAGE LOOKS QUITE ISOLATED. VFR CIGS EXPECTED BUT MAY DROP TO MVFR CONDITIONS IN HEAVIER SHOWERS. RAIN SHOULD COME TO AN END AFTER 00Z. HAVE NOT FOLLOWED THE LIFR CONDITIONS THE NAM GUIDANCE SUGGESTS FOR OVERNIGHT. THIS SEEMS TO BE THE ODD MODEL OUT BOTH AHEAD OF AND BEHIND THE FRONT WHICH WILL COME THROUGH OVERNIGHT GIVING US A WINDSHIFT TO THE NORTHWEST. && PREV DISCUSSION... /ISSUED 323 AM CDT MON MAR 19 2012/ DISCUSSION... TIMING OF PERIODS OF SHOWERS AND THUNDERSTORMS WILL BE THE MAIN FORECAST CONCERN IN THE SHORT TERM AS UPPER WAVE CUTS OFF OVER SOUTHERN TEXAS AND LINGERS THERE THROUGH THE PERIOD. A SURFACE TROUGH WAS LOCATED ACROSS WESTERN NEBRASKA AT 07Z SEPARATING DRY AIR TO THE WEST FROM MOIST AIR TO THE EAST. ISOLATED SEVERE STORMS HAD DEVELOPED JUST EAST OF THE TROUGH EARLIER IN THE EVENING. MAIN AREA OF CONVECTION EARLY THIS MORNING WAS OVER THE TEXAS PANHANDLE INTO SOUTHWEST KANSAS. SHORT RANGE HRRR GRADUALLY LIFTS THE STORMS NORTHEAST THROUGH THE MORNING WITH CURRENT TIMING BRINGING INITIAL ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS INTO EASTERN NEBRASKA AROUND 15Z. WEAK MID LEVEL INSTABILITY INDICATED BY FORECAST SOUNDINGS THROUGH THE MORNING WITH BETTER FORCING AND DEEPER MOISTURE IN THE AFTERNOON FROM SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA. EASTERN PORTION OF THE CWA IS INCLUDED IN SLIGHT RISK FOR SEVERE TODAY WITH STRONG SHEAR BUT LIMITED CAPE INDICATED BY CURRENT FORECAST SOUNDINGS. THIS INITIAL WAVE THEN SHIFTS EAST INTO THE MISSISSIPPI VALLEY TONIGHT WITH POPS DECREASING ACROSS THE AREA. A SECONDARY SURFACE WAVE LIFTS NORTH FROM THE SOUTHERN PLAINS ON TUESDAY BRINGING ANOTHER CHANCE OF THUNDERSTORMS TO THE AREA... ESPECIALLY TUESDAY AFTERNOON AND TUESDAY EVENING. SURFACE FRONT ASSOCIATED WITH THIS WAVE BECOMES QUASI-STATIONARY OVER WESTERN IOWA DURING THIS TIME WITH SOME POTENTIAL FOR LOCALLY HEAVY RAIN FROM EXTREME SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA...ALTHOUGH CURRENT FORECAST TRENDS PLACE AXIS OF HEAVY RAIN JUST EAST OF THE AREA. POPS AGAIN DECREASE TUESDAY NIGHT OVER THE AREA AS SURFACE WAVE LIFTS NORTHEAST AND WEAKENS. CLOSED UPPER LOW OVER TEXAS BEGINS TO IMPACT THE AREA ON WEDNESDAY AND WEDNESDAY NIGHT AS THE SYSTEM LIFTS NORTH BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS INTO THE AREA. TEMPERATURES EXPECTED TO STAY ON THE MILD SIDE ALTHOUGH THE CLOUD COVER AND PRECIP WILL KEEP READINGS COOLER THAN SEEN THE PAST FEW DAYS. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
141 PM EDT MON MAR 19 2012 .SYNOPSIS... SOUTHERLY FLOW ON THE BACKSIDE OF HIGH PRESSURE WILL ALLOW AN UNSEASONABLY WARM AIRMASS TO PERSIST THROUGH MUCH OF THE WEEK. DISTURBANCES IN THE UPPER ATMOSPHERE INTERACTING WITH AN UNSTABLE AIRMASS WILL PRODUCE A CHANCE OF THUNDERSTORMS TODAY. AN UPPER LEVEL HIGH WILL MOVE IN LATE MONDAY WHICH WILL BRING AN END TO THE THUNDERSTORMS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HEAT AND INSTABILITY WILL AGAIN GROW ACROSS THE FORECAST AREA TODAY. NO SIGNIFICANT CHANGES WERE NEEDED FOR THE MAX TEMP FORECAST...WHICH CURRENTLY BRINGS HIGHS TO NEAR THEIR RECORD VALUES (CVG 81...CMH 77...DAY 78). STEEP MID LEVEL LAPSE RATES WILL ALLOW FOR INSTABILITY TO DEVELOP TODAY...WITH AROUND 1000 J/KG OF MLCAPE EXPECTED (MAYBE 1500 IN SPOTS). HOWEVER...THE CWA WILL BE NEAR THE CENTER OF A MID LEVEL RIDGE...AND WIND SHEAR TODAY IS AT THE LOW END OF THE SPECTRUM. AT THIS TIME...THE RECENT HRRR RUNS SEEM TO BE ON THEIR OWN IN TERMS OF DEVELOPING A SIGNIFICANT AMOUNT OF THUNDERSTORMS OVER THE CWA. WITH LITTLE IN THE WAY OF DISCERNIBLE FORCING...IT IS MORE LIKELY THAT SHOWER AND THUNDERSTORM DEVELOPMENT WILL BE MOSTLY DISORGANIZED AND DIURNALLY DRIVEN. THE INSTABILITY IS PROBABLY ENOUGH TO WARRANT A RISK OF A STRONG STORM...BUT THE LACK OF SHEAR AND FORCING SEEM TO PRECLUDE A MORE WIDESPREAD SEVERE THREAT. TAILORED THE POPS A BIT WITH THE SLIGHTLY HIGHER CHANCE SHIFTING NORTH THROUGH TIME...EXITING THE SOUTHERN CWA BY EVENING AND THE NORTHERN CWA BY EARLY IN THE OVERNIGHT PERIOD. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... UPPER RIDGE BECOMES MORE ESTABLISHED TONIGHT...FORCING THE CONVECTION E. THE RIDGE WILL THEN REMAIN IN PLACE FOR THE REST OF THE PERIOD...KEEPING ANY CONVECTION CAPPED. TEMPERATURES WILL STAY UNSEASONABLY WARM. HIGHS WILL BE AROUND 80 EACH DAY AND WILL BE CLOSE TO OR ABOVE RECORD HIGHS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGHLY AMPLIFIED MID/UPPER LEVEL FLOW PATTERN WITH A LARGE SPRAWLING RIDGE CONTINUING TO INFLUENCE OUR WEATHER AT THE BEGINNING OF THE LONG TERM PERIOD. PREFER SLOWER ECMWF SOLN GIVEN HIGH DEGREE OF AMPLIFICATION. THIS WILL CONTINUE TO PROVIDE UNSEASONABLY WARM TEMPS AND DRY WEATHER WEATHER THRU MID WEEK. HAVE MAINTAINED A DRY FCST FOR THURSDAY. EXPECT HIGHS TO RANGE FROM THE UPPER 70S NORTH TO 80 SOUTH ON BOTH WED AND THU. AGAIN RECORD HIGH TEMPERATURES WILL BE IN JEOPARDY. RECORD HIGHS FOR WED ARE 82 AT CVG, 78 AT DAY AND 77 AT CMH. THE RECORDS FOR THURSDAY ARE WARMER WITH...85 CVG, 84 AT DAY AND 82 AT CMH. NUMERICAL MODELS CONTINUE TO TREND SLOWER BUT ARE HAVING A DIFFICULT TIME WITH CONSISTENCY REGARDING EASTWARD PROGRESSION OF UPPER LOW OVER THE NATIONS MID SECTION. WILL INTRODUCE LOW POPS INTO THE SW EARLY FRIDAY AND THEN SPREAD CHC POPS NE ACRS THE FA DURG THE DAY. WL BUMP POPS UP TO HIGH CHC EARLY SATURDAY WITH THE APPROACH OF SFC FRONTAL BOUNDARY. UNDER CONTD INFLUENCE OF THE UPPER LOW...WL CONTINUE LOW POPS THRU SAT AND THEN DIMINISH TO SLIGHT CHC ON SUNDAY AS THE INFLUENCE OF THE UPPER LOW BEGINS TO SHIFT SE. HIGH TEMPS WILL COOL BUT REMAIN ABOVE NORMAL...WITH FCST HIGHS IN THE UPPER 60S/70S ON FRIDAY AND LOWER AND MID 60S SATURDAY AND THEN UPPER 50S/LOWER 60S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS SHOULD CONTINUE TODAY FOR THE MOST PART. SOME SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP...ESPECIALLY IN CENTRAL AND WEST CENTRAL OHIO. GIVEN THE EXPECTED COVERAGE (WIDELY SCATTERED) HAVE INCLUDED VCSH IN THE TAFS FOR NOW AND WILL CONTINUE TO MONITOR THE SITUATION. OVERNIGHT...SOME FOG WILL BE POSSIBLE WHERE THE MOISTURE IS A BIT HIGHER IN CENTRAL OHIO...AND ALSO AT KLUK. WINDS WILL SHIFT TO THE SOUTHEAST AND BECOME RATHER LIGHT. LITTLE IN THE WAY OF SIGNIFICANT WEATHER IS EXPECTED ON TUESDAY...WITH SOUTHERLY FLOW AND VFR CLOUDS. OUTLOOK...THUNDERSTORMS ARE POSSIBLE ON FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HATZOS SHORT TERM...SITES LONG TERM...AR AVIATION...HATZOS
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1247 PM CDT MON MAR 19 2012 .DISCUSSION...UPDATED FOR 18Z AVIATION. && .AVIATION...COUPLE OF AVIATION CONCERNS FOR THIS TAF CYCLE. DEEPENING UPPER LEVEL SYSTEM OUT WEST HAS PRODUCED STRONG PRESSURE GRADIENT ACROSS AREA...WITH STRONG SOUTHEASTERLY WINDS ACROSS THE TERMINALS. AWW FOR CORPUS CHRISTI FOR 35 KNOT GUSTS WILL CONTINUE UNTIL 6 PM. LOW CLOUDS HAVE SCATTERED OUT AT ALL TERMINALS EXCEPT FOR ALI BUT EXPECT ALI TO IMPROVE TO VFR SHORTLY. CONVECTION WILL BE THE OTHER ISSUE. THUNDERSTORMS INITIALLY MAY INTO THE WESTERN PARTS OF THE BRUSH COUNTRY THIS EVENING...AND INCLUDED CB REMARKS FOR LRD. INSERTED VCTS AT ALI/CRP/VCT TO ACCOUNT FOR SQUALL LINE THAT WILL PROGRESS W TO E ACROSS THE BRUSH COUNTRY/COASTAL BEND REGIONS. ALSO EXPECT CIGS TO LOWER ONCE AGAIN TONIGHT BACK INTO THE MVFR RANGE AND PERHAPS IFR DUE TO THE PERSISTENT ONSHORE FLOW. INTRODUCED WIND SHIFT TO THE NORTH AT THE TERMINALS AS FRONT MOVES THROUGH. && .PREV DISCUSSION... /ISSUED 704 AM CDT MON MAR 19 2012/ DISCUSSION...UPDATED FOR 12Z AVIATION. AVIATION...SHOWERS HAVE MAINLY MOVED OUT OF THE AREA AS OF 12Z...ALTHOUGH A FEW SHOWERS ARE STILL IN THE VICINITY OF VICTORIA. EXPECT CIGS TO IMPROVE THROUGH THE DAY...WITH LRD EXPECTED TO GO SCT OR FEW IN THE AFTERNOON. GUSTY WINDS CONTINUE THROUGH THE DAY WITH A LLJ CONTINUING OVER THE AREA. TONIGHT WITH A 40-50KT LLJ ACROSS THE AREA AND AN APPROACHING COLD FRONT WILL SEE SHOWERS AND THUNDERSTORMS DEVELOPED. HAVE INCLUDED TSRA IN ALL TAFS EXCEPT LRD WHERE CHANCES ARE A BIT LOWER. THESE SHOWERS AND STORMS HAVE THE POTENTIAL TO BRING VERY STRONG WIND GUSTS. THE COLD FRONT WILL APPROACH THE LAREDO AREA LATE IN THIS TAF PERIOD...AND MOVE ACROSS THE AREA THE REST OF TUESDAY MORNING. PREV DISCUSSION... /ISSUED 433 AM CDT MON MAR 19 2012/ SHORT TERM (TODAY AND TONIGHT)...ISOLATED SHOWERS AND A COUPLE OF THUNDERSTORMS ARE ONGOING AT THE BEGINNING OF THE PERIOD ASSOCIATED WITH A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE MOST CONCENTRATED AREA OF SHOWERS AND STORMS HAS BEEN CLOSELY ASSOCIATED WITH A VORT MAX PROGGED WELL IN THE RUC MODEL. THE VORT MAX CONTINUES TO WEAKEN AS IT PUSHES TO THE NORTHWEST AND AS EXPECTED SHOWERS ARE WEAKENING AS WELL...WITH JUST A FEW LIGHTNING STRIKES REMAINING. THINK MOST OF TODAY WILL BE DRY ACROSS SOUTH TEXAS WITH JUST SOME ISOLATED LIGHT SHOWERS POSSIBLE WITH ADDITIONAL WEAK SHORT WAVES PROPAGATING AROUND MAIN TROUGH. MODEL SOUNDINGS INDICATE SIGNIFICANT CLEARING EVEN POSSIBLY IN WESTERN CWA. THIS WOULD ALLOW TEMPERATURES IN WEBB COUNTY TO INCREASE QUITE A BIT...CURRENTLY FORECASTING HIGHS IN THE MID 90S...BUT CAN`T DISCOUNT THE POSSIBILITY OF SOME AREAS GETTING A COUPLE OF DEGREES WARMER IF SKIES CLEAR. WITH LLJ NOT WEAKENING MUCH THROUGH THE DAY TODAY SHOULD MIX DOWN SOME GUSTS TO AROUND 40MPH THIS AFTERNOON SO HAVE ISSUED WIND ADVISORY FOR EASTERN HALF OF FORECAST AREA. THE FOCUS OF THE SHORT TERM FORECAST RESIDES IN THE POTENTIAL FOR THUNDERSTORMS TONIGHT AS THE COLD FRONT APPROACHES. INGREDIENTS LOOK DECENT FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY IN THE NORTHERN COUNTIES. SOUTHERN BRANCH OF SPLIT UPPER JET IS PROGGED A BIT FARTHER SOUTH TONIGHT THAN MODEL GUIDANCE WAS INDICATING LAST NIGHT. THIS SHOULD HELP THE CAUSE FOR DEVELOPMENT. WIND THREAT WOULD BE THE GREATEST SEVERE THREAT...AS 40-50KT LOW LEVEL JET WILL BE DIRECTLY OVERHEAD TONIGHT COINCIDING WITH THE THUNDERSTORMS. WITH SLIGHTLY SLOWER TIMING OF TROUGH...BEST CHANCE FOR SEVERE WILL BE AFTER MIDNIGHT ACROSS THE AREA...WITH THE NORTH AND NORTHEAST PART OF THE FORECAST AREA BEING THE MAIN TARGET. MODEL SOUNDINGS FOR VICTORIA INDICATE 1500J/KG CAPE OVERNIGHT...WITH LI/S AROUND -5. LAPSE RATES ARE ONLY MODERATE IN THIS REGION HOWEVER...IN THE 5-7C/KM RANGE. HAVE INCLUDED SEVERE WORDING ON FORECAST MAINLY FOR THE NORTHERN 2/3 OF THE FORECAST AREA. SPC HAS A SLIGHT RISK FOR SEVERE WEATHER ACROSS MOST OF THE FORECAST AREA...WITH A MODERATE RISK IN CENTRAL TEXAS. LONG TERM (TUESDAY THROUGH SUNDAY)...MAIN ISSUE THIS FORECAST PACKAGE IS WHETHER TO PLACE POPS IN AFTER TUESDAY AFTERNOON...WITH GENERALLY KEEPING SIMILAR POPS FOR TUESDAY AS ADVERTISED IN PREVIOUS PACKAGES. SPC HAS SLIGHT RISK ON BORDER OF AREA FOR DAY 2...AND WILL GENERALLY NOT SWAY FROM THIS). MODELS HAVE BEEN SHOWING THAT...AFTER THE MCS COMES ACROSS ON TUESDAY (NSSL AND NCEP WRF MODELS ARE KEEPING BIG CONVECTION TO THE NORTH THROUGH 12Z TUESDAY AND EXTRAPOLATION KEEPS THEM NORTH)...SOME DRYING OCCURS TUESDAY AFTERNOON UP TO 850 MB THEN SOME WRAP-AROUND MOISTURE FROM THE 700-300 MB LAYER COMES IN DURING THE LATE AFTERNOON THROUGH TUESDAY NIGHT (DRYING FROM WEST TO EAST AFTER MIDNIGHT TUESDAY EVENING). THIS IS A POTENT UPPER SYSTEM...AND MODELS FOR DAYS HAVE BEEN TOYING WITH POSSIBLE ADDITIONAL RAINFALL TUESDAY NIGHT. GIVEN THE FACT THE MODEL CONSENSUS IS SLOWING UPPER SYSTEM DOWN SOME...AND GUIDANCE IS GOING NEARLY LIKELY ON THE RAINFALL (THINK THIS IS OVER-DONE)...HAVE DECIDED TO INCLUDE POPS TUESDAY NIGHT MAINLY OVER THE EASTERN HALF OF CWFA. COULD EVEN SEE SOME THUNDER OVER THE EXTREME EASTERN AREAS/GULFMEX TUESDAY NIGHT. FARTHER WEST...SPRINKLES AT BEST. AFTER TUESDAY NIGHT...THINK UPPER SYSTEM WILL BE FAR ENOUGH NORTH AND SUFFICIENT DRYING OVER THE AREA TO END RAIN (GFS-MOS STILL HAS CHANCE POPS EASTERN AREAS BUT WILL IGNORE THIS). MODELS ARE RELATIVELY CONSISTENT UNTIL THE END OF THE WORK WEEK IN KEEPING A WEAK UPPER RIDGE OVER THE AREA...THEN DIVERGE OVER THE WEEKEND WITH THE GFS PUSHING THE RIDGE EAST AND MOVING A TROUGH TOWARD THE WESTERN CWFA LATE SUNDAY. THE ECMWF HOWEVER KEEPS THE RIDGE OVER THE AREA (BUT NOT BRINGING A BOUNDARY DOWN LIKE IT DID ON YESTERDAY`S 00Z RUN). FOR NOW...WILL KEEP THE FORECAST RAIN-FREE BUT BRING IN THE MOISTURE A LITTLE FASTER THAN BEFORE AND INCREASE OVERNIGHT TEMPERATURES SOME. OVERALL...TENDED TO GO MORE WITH THE WARMER FORECAST NUMBERS THROUGH THURSDAY MORNING...THEN OVERALL DID A CONSENSUS FORECAST BETWEEN THE ECMWF AND GFS SOLUTIONS FOR TEMPERATURES AND MOST OTHER PARAMETERS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 72 83 54 75 54 / 50 60 30 10 0 VICTORIA 70 74 53 72 51 / 70 80 40 10 10 LAREDO 68 83 53 81 54 / 40 20 10 10 0 ALICE 72 82 53 78 51 / 50 50 20 10 0 ROCKPORT 71 78 56 72 59 / 50 70 40 10 0 COTULLA 62 77 49 78 50 / 70 30 10 10 10 KINGSVILLE 71 83 52 77 51 / 50 50 30 10 0 NAVY CORPUS 71 81 57 73 59 / 50 70 40 10 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...GOLIAD...JIM WELLS... KLEBERG...LIVE OAK...NUECES...REFUGIO...SAN PATRICIO... VICTORIA. GM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. && $$ TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1231 PM CDT MON MAR 19 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 339 AM CDT MON MAR 19 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES AND HOW WARM TO GO WITH TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING OVER THE WESTERN U.S. AND STRONG RIDGING FROM THE SOUTHEASTERN U.S. INTO THE WESTERN GREAT LAKES REGION. WITHIN THE SOUTH-SOUTHWEST FLOW AHEAD OF THE TROUGH...IT IS TOUGH TO FIND ANY SHORTWAVES OF NOTE ON WATER VAPOR. THIS IS PRIMARILY DUE TO PLENTIFUL PACIFIC MOISTURE AND BLOW-OFFS FROM EVENING CONVECTION OVER THE SOUTHERN PLAINS. RUC ANALYSIS SHOWS VERY FEW AS WELL. AHEAD OF THE DEEP TROUGH...A SOUTHWEST 40-60 KT 850MB JET EXISTS OVER THE PLAINS INTO THE FORECAST AREA...HELPING TO MAINTAIN A CONTINUOUS FEED OF MOISTURE TRANSPORT FROM THE GULF OF MEXICO. PRECIPITABLE WATER VALUES ON 00Z SOUNDINGS REFLECT THE MOISTURE TRANSPORT... RANGING FROM 1-1.3 INCHES FROM GRB TO OAX...DVN...TOP AND FWD. THESE ARE 250-310 PERCENT ABOVE NORMAL. DESPITE ALL OF THIS MOISTURE... THERE IS VERY LITTLE OCCURRING ON REGIONAL RADARS...AND AGAIN THIS MIGHT BE DUE TO LACK OF NOTABLE SHORTWAVE FEATURES. IN ADDITION...ALTHOUGH THE ENVIRONMENT HAS A LOT OF MOISTURE WITH RESPECT TO NORMAL...00Z SOUNDINGS FROM OAX...DVN AND MPX WERE ACTUALLY FAIRLY DRY OUTSIDE OF THE 800MB MOISTURE JUST BELOW THE CAP. NEAREST PRECIPITATION ON RADAR IS IN MISSOURI AND WESTERN KANSAS. THE BREEZY SOUTHERLY FLOW...AHEAD OF A 982MB LOW IN EASTERN MONTANA...HAS HELPED TO KEEP TEMPERATURES UP IN THE 60S AND DEWPOINTS IN THE MID TO UPPER 50S. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE UPPER LEVEL PATTERN THROUGH THE SHORT TERM...ALL SHOWING THE CURRENT WESTERN TROUGH MOVING INTO THE WESTERN PLAINS ON TUESDAY...THEN SPLITTING APART. THE MAIN TREND IS THAT THE SOUTHERN END WHICH CUTS OFF INTO AN UPPER LOW IS FARTHER SOUTH AND WEST FOR WEDNESDAY AND WEDNESDAY NIGHT. THIS RESULTS IN RIDGING BUILDING BACK WESTWARD INTO THE FORECAST AREA WEDNESDAY NIGHT. DESPITE THE GOOD AGREEMENT ON THE UPPER PATTERN...DETAILS ARE MURKY AT BEST...ESPECIALLY WHEN IT COMES TO PRECIPITATION. THE REASONS ARE TWO FOLD: 1. HAVING THE ABNORMALLY HIGH MOISTURE STREAM EXPECTED TO STAY PUT OVER THE FORECAST AREA THROUGH THE SHORT TERM PERIOD...AND 2. ANY WEAK SHORTWAVE FORCING COULD ACT ON THE MOISTURE STREAM AND CAUSE PRECIPITATION TO OCCUR. THE DAILY DISCUSSIONS BELOW REPRESENT THE BEST ATTEMPT TO FIGURE OUT THE DETAILS. TODAY AND TONIGHT...THERE ARE INDICATIONS BY THE 19.00Z NAM/GFS/REGIONAL CANADIAN OF A WEAK SHORTWAVE COMING OUT OF MISSOURI AND LIFTING NORTHEAST THROUGH THE FORECAST AREA TODAY. THE NAM AND GFS BOTH PRODUCE PRECIPITATION WITH THIS SHORTWAVE...LIKELY OCCURRING IN THE 15-21Z TIME PERIOD...WHEREAS THE REGIONAL CANADIAN ONLY PRODUCES PRECIPITATION NEAR GRANT COUNTY. THE 19.03-19.05Z HRRR RUNS HAVE LOOKED A LOT LIKE THE REGIONAL CANADIAN AS WELL...GIVING A LITTLE MORE CONFIDENCE TOWARDS A DRIER SOLUTION. GIVEN THE FACT THAT IT IS TOUGH TO FIND ANY NOTABLE SHORTWAVE IN WATER VAPOR AND THE DRIER 00Z SOUNDING LOOK...HAVE LOWERED PRECIPITATION CHANCES TODAY TO MOSTLY 20-40 PERCENT. DOES SEEM THAT THE AFTERNOON WOULD HAVE BETTER POTENTIAL GIVEN THAT MUCAPE VALUES COULD RANGE FROM 500-1500 J/G...SO THE 40 PERCENT EXIST THEN. STILL...IT IS HARD TO FIND A TRUE TRIGGER IN THE AFTERNOON WITH LITTLE IF ANY HEIGHT FALLS OR SHORTWAVE COMING ACROSS. NOTE THAT WHERE THE HIGHEST CAPE EXISTS...0-6/0-3KM SHEAR IS LESS THAN 25 KT...SUGGESTING STORM ORGANIZATION AND SEVERE WEATHER IS NOT ANTICIPATED. ANOTHER ROUND OF PRECIPITATION WHICH LOOKS MORE CERTAIN WILL MOVE INTO AREAS WEST OF THE MISSISSIPPI RIVER THIS EVENING. THIS PRECIPITATION IS ASSOCIATED WITH A DEEPER WARM CONVEYOR BELT SURGE COMING OUT OF THE SOUTHERN PLAINS. HOWEVER...A LOT OF UNCERTAINTY EXISTS IF THE PRECIPITATION WILL MOVE EAST OVERNIGHT AND HOW MUCH OF IT STAYS INTACT. THE REASON FOR THIS UNCERTAINTY IS THAT IT APPEARS THE WARM CONVEYOR MAY SPLIT APART AS IT PUSHES EAST INTO THE UPPER RIDGING...LIKE THE SPLIT OCCURRING WITH THE WESTERN UPPER TROUGH. THEREFORE FOR TONIGHT BEST CHANCES FOR PRECIPITATION...IN THE 60-70 RANGE...WILL STAY WEST OF THE MISSISSIPPI RIVER. TUESDAY THROUGH WEDNESDAY NIGHT...WITH THE TREND FOR THE UPPER LEVEL TROUGH TO SPLIT SOONER...THE OVERALL FORECAST FOR THIS TIME PERIOD LOOKS DRIER...ESPECIALLY FOR WISCONSIN. PRECIPITATION FORECASTS THAT WERE MOSTLY OVER THE AREA HAVE NOW SHIFTED WEST TO HANDLE THE FARTHER WEST UPPER TROUGH AND SURFACE COLD FRONT. AS SUCH...CHANCES HAVE BEEN REDUCED. REGARDING A FEW DETAILS...TUESDAY MORNING COULD BE QUIET AS DEPICTED BY THE REGIONAL CANADIAN AND GFS...RESULTING FROM THE WARM CONVEYOR BELT FALLING APART. THIS IS ONLY TEMPORARY BECAUSE IN THE AFTERNOON A NEW SURGE OF SHOWERS AND EMBEDDED THUNDER SHOULD COME UP THROUGH THE WEST HALF OF IOWA AND POSSIBLY ENTER SOUTHEAST MINNESOTA. VERY GOOD AGREEMENT EXISTS ON THIS...RESULTING FROM A SHORTWAVE EJECTING OUT OF THE UPPER TROUGH. FOR TUESDAY NIGHT...THIS SURGE OF PRECIPITATION AGAIN LOOKS TO STAY MORE TO OUR WEST AND NORTHWEST...AGREED TOO WITH THE NEW 19.00Z ECMWF. IT IS CONCEIVABLE NOW THAT WEDNESDAY ENDS UP DRY AS UPPER LEVEL AND FRONTOGENETICAL FORCING WANES...BUT FOR NOW HAVE MAINTAINED SOME LOW CHANCES PER CONTINUITY AND STILL SOME WEAK FORCING INDICATIONS. THAT FRONTOGENETIC FORCING MAY TRY TO STRENGTHEN BACK UP WEDNESDAY NIGHT IF THE UPPER LOW KICKS OUT AS PROGGED. THUS HIGHER CHANCES ARE INDICATED THEN. REGARDING TEMPERATURES THROUGHOUT THE SHORT TERM...GIVEN THE PERIODIC ROUNDS OF PRECIPITATION...HIGHS ARE DIFFICULT TO FORECAST. 850MB TEMPS HOLD BETWEEN 10-12C AND THE TRUE SURFACE COLD FRONT... WHICH LOOKS LIKE IT ENDS UP FALLING APART...DOES NOT MOVE INTO THE AREA UNTIL WEDNESDAY NIGHT. IF ANY SUN OCCURS...TEMPERATURES COULD EASILY JUMP WELL INTO THE 70S AND POSSIBLY LOW 80S. FOR NOW STAYED WITH A BLEND OF GUIDANCE WHICH DID CAUSE AN INCREASE IN HIGHS FOR TUESDAY AND WEDNESDAY...RESULTING TOO FROM THE UPPER TROUGH SLOWING DOWN. LOWS ARE LIKELY TO REMAIN IN THE 50S TO LOW 60S...WARMEST TONIGHT. SEE CLIMATE SECTION BELOW FOR POSSIBLE RECORDS. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 339 AM CDT MON MAR 19 2012 OVERALL MUCH BETTER AGREEMENT EXISTS TODAY AMONGST THE 19.00Z GUIDANCE WITH THE HANDLING OF THE UPPER LEVEL PATTERN...INCLUDING THE UPPER LOW. IF ANYTHING...THE ECMWF HAS TRENDED COMPLETELY TOWARDS PAST AND CURRENT GFS RUNS...WHICH SUGGESTS A CONTINUATION OF ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THIS ALSO MATCHES CFS FORECASTS WHICH SUGGESTS THE SAME FOR THE MARCH 24TH THROUGH 28TH PERIOD. MAIN FOCUS FOR MUCH OF THE LONG TERM PERIOD IS ON THE UPPER LOW OVER THE SOUTHERN PLAINS WEDNESDAY NIGHT. GOOD AGREEMENT EXISTS THAT IT WILL LIFT NORTHEAST INTO NORTHERN MISSOURI BY FRIDAY IN RESPONSE TO DIGGING TROUGHING OFF THE U.S. WEST COAST. A WARM CONVEYOR BELT OF PRECIPITATION LOOKS TO FORM AHEAD OF THIS LOW AND IMPACT THE AREA THURSDAY AND THURSDAY NIGHT...POSSIBLY FRIDAY AS WELL IF THE GFS IS CORRECT. SIMILAR TO THE SHORT TERM PERIOD...PRECIPITABLE WATER VALUES ARE WELL ABOVE NORMAL...300 TO 350 PERCENT OR SO. RAISED PRECIPITATION CHANCES TO 40-50 AND FURTHER INCREASES MAY BE NECESSARY. SOME SHOWERS COULD STILL PERSIST FOR FRIDAY NIGHT AND SATURDAY AS THE UPPER LOW SCOOTS OFF TO THE EAST...AND WHILE THERE IS A RELATIVE COOL POOL OF AIR ALOFT. ANTICIPATING DRY CONDITIONS FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH UPPER RIDGING BUILDING OVER THE PLAINS IN THE WAKE OF THE UPPER LOW...AS WELL AS SURFACE RIDGING BUILDING IN AT THE SURFACE. BACK TO TEMPERATURES...DESPITE THE APPROACH OF THE UPPER LOW FOR THURSDAY AND FRIDAY AND ITS ASSOCIATED PRECIPITATION...BOTH MEX AND 19.00Z ECMWF 2 METER GRID GUIDANCE HAVE REALLY WARMED UP THIS TIME PERIOD. IN FACT...THE ECMWF SUGGESTS POTENTIAL FOR RECORD HIGHS ON THURSDAY. GIVEN THE FACT THAT THE ECMWF DOES CONSIDER PRECIPITATION IMPACTS ON TEMPERATURES...HAVE RAISED TEMPERATURES SOME OVER THE BLEND OF GUIDANCE. FURTHER INCREASES MAY BE NECESSARY. SHOULD SEE SOMEWHAT OF A COOL DOWN FOR THE WEEKEND...BUT 850MB TEMPS ONLY DROP TO 4-6C AT MOST. THIS WILL KEEP READINGS ABOVE NORMAL. && .AVIATION...THIS AFTERNOON THRU TUESDAY 1231 PM CDT MON MAR 19 2012 FCST CONFIDENCE FOR -SHRA/TSRA THIS AFTERNOON THRU TUE ON THE LOW SIDE. DEEP SOUTHERLY AND MOIST FLOW CONTINUES OVER THE AREA THRU TUE. HOWEVER MODELS DIFFER ON THE SUBTLE TRIGGER/FORCING MECHANISMS IN THIS MOIST SOUTH FLOW...WITH DIFFERENT OUTCOMES FOR SHRA/TSRA TIMING AND COVERAGE THE NEXT 24-36HRS. GENERAL CONSENSUS IS FOR PERIODIC CONVECTION WITH MAINLY SCT COVERAGE TO MOVE ACROSS THE FCST AREA THIS AFTERNOON THRU TUE. FOR THE REST OF THIS AFTERNOON... STRONGER OF WHAT FORCING THERE IS APPEARS TO BE ALONG/EAST OF THE MS RIVER AND INCLUDED MORE OF A SHRA/CB MENTION AT KLSE. THEN APPEARS THERE WILL BE A LULL FOR THE LATE AFTERNOON/EARLY EVENING HOURS WITH AN INCREASE OF FORCING/LIFT AS THE SFC-MID LEVEL TROUGH AXIS MOVE A BIT CLOSER TO THE AREA. CONTINUED A PERIOD OF -SHRA AT THE TAF SITES TONIGHT...MORE-SO AT KRST CLOSER TO THE TROUGH AXIS. ALSO INCLUDED CB MENTION IN THE 01-08Z TIME FRAME WITH SOME INSTABILITY OVER THE AREA...THEN JUST -SHRA LATER TONIGHT WITH MINIMAL INSTABILITY. WITH THE PERIODIC SCT -SHRA THIS AFTERNOON INTO TUE...CIGS EXPECTED TO GRADUALLY LOWER TO MVFR FOR LATER TONIGHT INTO TUE. GRADIENT REMAINS TIGHT FOR BRISK SOUTH/SOUTHEAST WINDS THIS AFTERNOON...THEN RELAXES FOR TONIGHT/TUE WITH APPROACH OF THE SFC TROUGH/FRONT. && .CLIMATE...THIS WEEK 339 AM CDT MON MAR 18 2012 TEMPERATURES LOOK TO GRADUALLY COOL THIS WEEK WITH PERIODS OF PRECIPITATION EXPECTED EACH DAY. HOWEVER...THIS PROCESS IS GOING TO BE VERY SLOW AS THE UNSEASONABLY WARM AIRMASS NEVER GETS FULLY SHUNTED EAST OF HERE UNTIL MAYBE THIS WEEKEND ACCORDING TO LATEST MODEL GUIDANCE. THEREFORE...POTENTIAL EXISTS EACH DAY FOR RECORD HIGHS AND MORE LIKELY RECORD HIGH MINIMUMS. CURRENT FORECAST PLAYS TEMPERATURES A LITTLE CONSERVATIVELY. IF MORE SUN OCCURS THAN FORECAST FOR TODAY...TUESDAY OR WEDNESDAY...RECORDS HIGHS ARE MORE LIKELY TO BE BROKEN. WEDNESDAY MAY BE THE TOUGHEST DAY TO BREAK RECORD HIGHS WITH MOST LOCATIONS HAVING RECORDS BETWEEN 75 TO 80...EXCEPT ROCHESTER AND MEDFORD WHICH ARE AT 70. FOR A LIST OF WHAT HAS OCCURRED REGARDING RECORDS THUS FAR AS WELL AS THOSE THAT COULD FALL IN THE DAYS TO COME...PLEASE SEE THE TOP NEWS STORY ON OUR WEBSITE ON THE UNSEASONABLY WARM MARCH. && .ARX WATCHES/WARNINGS/ADVISORIES... 339 AM CDT MON MAR 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DAS CLIMATE......AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1220 PM CDT MON MAR 19 2012 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY THROUGH TUESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AMPLIFIED UPPER PATTERN ACROSS THE CONTINENT EARLY THIS MORNING...WITH A LARGE UPPER TROUGH OVER THE INTER-MOUNTAIN WEST AND SUBTROPICAL RIDGING CENTERED OVER THE CENTRAL GREAT LAKES. A LARGE PLUME OF MOISTURE IS HEADING NORTHEAST OVER THE GREAT PLAINS THOUGH PRECIP ECHOES ARE WIDELY SCATTERED OVER MISSOURI AND KANSAS. ONE SHORTWAVE OF NOTE IS EMBEDDED IN THE SW TROPICAL FLOW OVER KANSAS...BUT IS FAIRLY INACTIVE AT THE MOMENT. PLENTY OF CAPPING IN PLACE AS DEPICTED ON 00Z RAOBS OVER THE REGION. CLOSER TO HOME...AREA OF 6-7KFT CU HAS BEEN EXPANDING OVER FAR NE WISCONSIN AND THE EASTERN UPPER PENINSULA. AS MOISTURE STREAMS INTO THE REGION FROM THE CENTRAL PLAINS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN OVER THE NEXT 36 HOURS. TODAY...LARGE TROUGH OVER THE WEST WILL SLOWLY SLIDE ACROSS THE ROCKIES WHILE MID-LEVEL RIDGING WILL BUILD OVER THE CENTRAL GREAT LAKES. SLUG OF TROPICAL MOISTURE FROM THE SOUTHERN PLAINS WILL LIFT NORTH INTO WISCONSIN LATE IN THE MORNING AND THROUGH THE AFTERNOON...WITH PWATS CLIMBING TO GREATER THAN 1.25 INCHES...WHICH IS NEAR THE HIGHEST ON RECORD FOR THE MONTH OF MARCH. AS THE COLUMN MOISTENS...MODELS PROJECT THE STRONG CAP IN PLACE ACROSS THE REGION PARTIALLY ERODES...THOUGH THE NAM COMPLETELY WIPES IT OUT. BASED ON UPSTREAM SOUNDINGS...DO NOT THINK THIS IS REASONABLE. INSTEAD...WILL GO MORE WITH THE GFS IDEA OF KEEPING A WEAKENED CAP AROUND. BUT EVEN WITH A WEAKENED CAP...MODIFIED PROGGED SOUNDINGS OVER CENTRAL WISCONSIN USING A 74/58 PARCEL YIELDS ABOUT 900 J/KG OF ML CAPE AND NO CIN. WILL HAVE TO GET TO THE MIDDLE 70S TO REACH THE CONVECTIVE TEMPERATURE TO GET PAST THE CAP THIS AFTERNOON. LACK OF UPSTREAM ECHOES AND TRIGGERS LEADS ME TO GO DRY ACROSS MOST OF THE AREA THROUGH THE MORNING. IMPULSE OVER KANSAS SHOULD APPROACH THE REGION IN THE AFTERNOON WHICH COULD INTERACT WITH DAYTIME INSTABILITY TO CREATE SCT SHOWERS AND TSTORMS. STILL NOT THINKING ANYTHING SEVERE TODAY...BUT SOME OF THE STRONGEST STORMS COULD PRODUCE SMALL HAIL AND BRIEF GUSTY WINDS. WILL HAVE MORE CLOUD COVER AND MOISTURE AROUND THAN YESTERDAY...THOUGH LOOK TO BE OFF TO A WARMER START THAN YESTERDAY TOO. WILL GO WITH TEMPS A DEGREE OR TWO COOLER. TONIGHT...THE AIRMASS CHANGES VERY LITTLE AS THE DEEP TROUGH OVER THE WESTERN HARDLY MOVES TO THE EAST. AS MOIST AS THE COLUMN APPEARS...WOULD NOT TAKE MUCH OF A FEATURE OR SHORTWAVE IMPULSE TO TRIGGER SHOWERS AND ISOLD TSTORMS. WILL KEEP A MENTION OVER THE WESTERN 2/3RDS OF THE FORECAST AREA. SHOULD SEE A WARMER AND MORE MUGGY NIGHT...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S AWAY FROM LAKE MICHIGAN. TUESDAY...SOUTHERN PIECE OF THE WESTERN TROUGH CUTS OFF OVER WESTERN TEXAS WHILE SURFACE LOW PRESSURE TRAVELS NORTH OVER THE CENTRAL PLAINS. COLD FRONT ATTACHED TO THE LOW WILL SUBTLY SHIFT EAST TO THE MN/WI BORDER BY LATE IN THE AFTERNOON. AIRMASS CHANGES VERY LITTLE...BUT PROGGED SOUNDINGS SHOW SOME DRYING IN THE MID-LEVELS THAT LEADS TO SLIGHTLY LESS INSTABILITY THAN PROGGED FOR TODAY. THAT WONT LEAD TO A BIG CHANGE (IF ANY) IN THE FORECAST THOUGH AND WILL KEEP POPS ACROSS THE WESTERN 2/3RDS OF THE FORECAST AREA. HIGHS PERHAPS A FEW DEGREES COOLER OVER NORTH-CENTRAL WISCONSIN DUE TO CLOUD COVER AND POTENTIAL PRECIP...THOUGH LITTLE CHANGE IN TEMPS FARTHER EAST. .LONG TERM...TUESDAY NIGHT THRU SUNDAY. MAIN FORECAST CONCERNS ARE TEMPS AND PRECIP CHANCES. HIGHLY AMPLIFIED PATTERN WHICH HAS DOMINATED FOR THE PAST SEVERAL DAYS WITH A DEEP TROUGH OVER THE WESTERN U.S. AND RIDGING OVER THE EASTERN U.S. WILL SLOWLY TRANSITION TO MORE OF A SPLIT FLOW AS CUT OFF UPPER LOW SITS AND SPINS IN THE SOUTHERN PLAINS AND MORE OF A ZONAL FLOW DEVELOPS ACROSS THE NORTHERN U.S. AND SOUTHERN CANADA. MODEL TRENDS HAVE BEEN TO STALL THE UPPER LOW WELL TO OUR SW...KEEPING WARMER TEMPS ACROSS THE AREA LONGER...AND HOLDING OFF BEST PRECIP CHANCES UNTIL LATER THIS WEEK. PINNING DOWN BEST CHANCES FOR PRECIP WILL BE VERY CHALLENGING AS MODELS HAVE NOT REMAINED CONSISTENT ENOUGH TO HAVE CONFIDENCE IN ANY ONE SOLUTION. DUE TO THE MUCH SLOWER EASTWARD PROGRESSION OF THE UPPER LOW AS ADVERTISED BY THE LAST COUPLE OF MODEL RUNS... HAVE MADE SOME SIGNIFICANT CHANGES TO THE POPS AND CLOUDS GRIDS FOR MID-WEEK. FIRST CHANCE OF PRECIP WILL COME TUESDAY NIGHT AND WEDNESDAY AS FRONT CROSSES INTO THE STATE. STILL SOME UNCERTAINTY WITH HOW FAR SOUTH THE FRONT WILL GET. DECIDED TO PULL POPS FOR ALL BUT FAR NORTH-CENTRAL WI TUESDAY NIGHT...AND CHOPPED WEDNESDAY POPS TO CHANCE ACROSS CENTRAL AND NORTH-CENTRAL WI AND SLIGHTS OVER THE EAST...FAVORING A SLOWER SOLUTION...PLUS THE BEST FORCING WILL REMAIN CLOSER TO A UPPER JET NORTH OF THE REGION. REDUCED CLOUDS MAINLY ACROSS EASTERN WI AS WELL. MODELS HAVE HELD MOST OF THE ACTIVITY WITH THIS SYSTEM NW OF THE CWA...SO WOULD NOT BE SURPRISED IF WE MISS OUT ON THIS SYSTEM COMPLETELY IN THE SE...AND WILL ONLY KEPT THE SLIGHT CHANCE POPS TO COVER ANY ISOLATED ACTIVITY OUT AHEAD OF THE FRONT IN THE PERSISTENT MOIST SOUTH FLOW. HAVE INCREASED POPS FOR LATE IN THE WEEK AS MODELS NOW SHOW THE UPPER LOW WORKING INTO THE SOUTHERN GREAT LAKES...BUT CONFIDENCE REMAINS LOW AS HOW QUICKLY THE UPPER LOW WILL TOWARD THE AREA. WILL CONFINE THUNDER MENTION FOR THE DAYTIME HOURS... MAINLY THE AFTERNOON...ALTHOUGH CONVECTIVE PARAMETERS NOT VERY IMPRESSIVE WITH CLOUD COVER REDUCING INSTABILITY AND LAPSE RATES NOT TOO STEEP. THE RECORD BREAKING...OR NEAR RECORD BREAKING...WARMTH LOOKS TO CONTINUE INTO WEDNESDAY NOW...WITH 850/925MB TEMPS STILL SUPPORTIVE OF HIGHS IN THE MIDDLE TO UPPER 70S ACROSS EAST-CENTRAL WI. SLIGHTLY COOLER TEMPS ALOFT AND MORE CLOUDS EXPECTED AS YOU WORK TOWARD NW AND NORTH-CENTRAL WI...AS THE FRONT SAGS ACROSS THE STATE...SO EXPECT COOLER TEMPS THERE. THICKER CLOUD COVER AND/OR THE FRONT SAGGING FARTHER SOUTH COULD KEEPS TEMPS COOLER ACROSS THE AREA...HOWEVER FAVOR THE WARMER TEMPS. ABOVE NORMAL TEMPS ARE EXPECTED THROUGH THE UPCOMING WEEKEND...WITH NO COLD AIR IN SIGHT FOR THE AREA. EVEN AS UPPER LOW COMES CLOSER...IT SEEMS TO LOSE ITS SOMEWHAT CHILLY CORE...SO WILL BUMP UP TEMPS A LITTLE LATE IN THE WEEK. && .AVIATION...A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS WL CONT TO MOVE N-NE INTO NE WI THIS AFTERNOON AS A SHORTWAVE MOVES NE ACROSS IL. CIGS HAVE GENERALLY REMAINED AT VFR LEVELS AND EXPECT THIS TO PERSIST THRU THE AFTERNOON. VFR CONDITIONS ARE EXPECTED OVER MOST OF THE REGION TNGT...ALTHO SOME PATCHY FOG MAY ONCE AGAIN DEVELOP AT TIMES...ESPECIALLY WHERE THE RAINS FELL TODAY. VFR CONDITIONS ARE FCST FOR TUE AS WELL WITH A CHC OF ADDITIONAL SHWRS PRIMARILY OVER THE RHI...AUW AND CWA TAF SITES. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ AK