Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/07/13


AREA FORECAST DISCUSSION
NWS ALBANY NY
641 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONTAL BOUNDARY OVER THE NEW YORK PENNSYLVANIA BORDER...WILL KEEP CLOUDS ALONG WITH AN ISOLATED TO SCATTERED THREAT OF SHOWERS FOR THE FIRST HALF OF THIS WEEKEND. AS THE BOUNDARY MOVES NORTH OF THE CAPITAL REGION TONIGHT INTO SUNDAY...MORE WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE ACROSS THE REGION...ALONG WITH HIGHER HUMIDITY LEVELS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 630 AM EDT...A FEW LIGHT SHOWERS PER THE LATEST 88D SCANS WERE TRACKING ACROSS THE DACKS WITH A MORE CONCENTRATED AREA OF CONVECTION IN THE BUFFALO VICINITY. LATEST HRRR REFLECTIVITY FORECASTS SUGGESTS THIS UPSTREAM BAND OF CONVECTION SHOULD WEAKEN AS IT APPROACHES A MORE STABLE DOWNSTREAM AIR MASS. OTHERWISE...THE FRONTAL BOUNDARY HAS MOVED LITTLE WITH THE BETTER PROGRESS ACROSS SOUTHWEST NY STATE. NO OTHER CHANGES AT THIS TIME. PREV DISC... QUASI-STATIONARY BOUNDARY WAS SITUATED ALONG THE NY/PA BORDER. REGIONAL RADAR MOSAIC REVEALS WIDELY SCATTERED SHOWERS ACROSS CENTRAL AND WESTERN NY WITH MORE ROBUST CONVECTION ACROSS LOWER MICHIGAN AND APPROACHING LOWER ONTARIO PROVENCE. H2O VAPOR LOOP DOES HINT AT A WEAK SHORT WAVE EMBEDDED WITHIN THE WESTERLY FLOW NORTH OF THIS FRONTAL BOUNDARY THAT IS THE LIKELY CULPRIT FOR THE AFOREMENTIONED DEEPER CONVECTION UPSTREAM. LATEST HOURLY RUN OF THE RUC13/HRRR AND 4KM SPC WRF MODELS SUGGEST THIS UPSTREAM SHOULD WEAKEN AS IT OUTRUNS THE LOW LEVEL JET /AOA 20KTS/ AND ELEVATED INSTABILITY. MEANWHILE...SURFACE HIGH SITUATED NORTH OF THE GREAT LAKES REGION CONTINUES TO EXTEND ITS INFLUENCE EAST AND SOUTHWARD WHICH WILL LIKELY KEEP THIS FRONTAL BOUNDARY FROM MOVING FURTHER NORTH THROUGH THE DAY. WITH THAT SAID...WE REMAIN ON THE COOLER SIDE OF THE BOUNDARY WITH CONSIDERABLE CLOUD COVER AND THE CHANCE /SLIGHT-CHC FOR SOME SHOWER ACTIVITY. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE...CLOSER TO THE MET MOS VALUES AND HOURLY LAMP/LAV. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... 00Z NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE HAVE RESULTED IN A LARGER SHIFT TOWARD A SLOWER MORE AMPLIFIED PATTERN. THE RESULT IS A SLOWER TIMING OF THE WARM FRONTAL PASSAGE TO BE FOLLOWED BY THE COLD FRONT LATE MONDAY OR MONDAY NIGHT. TONIGHT...THE LOW LEVEL JET UPSTREAM WILL INCREASE IN EARNEST AS PRECIPITATION/CONVECTION UNFOLD. THE BEST WARM ADVECTION AND ISENTROPIC LIFT IS EXPECTED TO OCCUR OVER WESTERN AND CENTRAL NY. PER THE CORFIDI VECTORS AND THICKNESS...THIS ACTIVITY WILL LIKELY SPREAD INTO THE WESTERN ZONES AND THE DACKS THROUGH THE OVERNIGHT AND GRADUALLY SPREAD ACROSS THE REMAINDER OF THE CWA. WE WILL GRADUALLY INCREASE POPS FROM WEST TO EAST AND KEEP TEMPERATURES A BIT STEADY AS THE WARMER AIR BEGINS TO ADVECT NORTHWARD. THROUGH SUNDAY...THE PROGRESS OF THIS WARM FRONT WILL BE INTERESTING TO WATCH AS THE SURFACE HIGH /1024MB/ NORTH OF THE GREAT LAKES MIGRATES ACROSS NORTHERN NEW ENGLAND AND KEEPING THE LOWER LEVEL AGEOSTROPHIC FLOW ACROSS THE HUDSON RIVER VALLEY AND POINTS EAST. ONCE AGAIN CONSIDERABLE CLOUD COVER ALONG WITH SHOWERS AS WE WILL FAVOR A MOS BLEND OF THE NAM/GFS. SUNDAY NIGHT...TRENDS ARE FAVORING FOR A MID LEVEL DRY SLOT TO ADVECT INTO THE REGION WHICH SHOULD REDUCE COVERAGE OF PRECIP BUT KEEP THE LOW LEVEL MOISTURE IN PLACE. IN FACT...CROSS SECTIONS REVEAL AMPLE WIND SHEAR AT OR JUST ABOVE THE LOW LEVEL MOISTURE THAT POCKETS OF DRIZZLE MAY DEVELOP. TEMPERATURES SHOULD BE A LITTLE MILDER. MONDAY...A FAIRLY DEEP UPR LOW ACROSS THE MID WEST AND ITS ASSOCIATED SURFACE LOW/COLD FRONT ARE EXPECTED TO SLOW THE FORWARD PROGRESSION OF THIS SYSTEM. THIS WILL LIKELY PLACE OUR REGION WELL WITHIN THE WARM SECTOR...HOWEVER...MARINE INFLUENCE COMPONENT REMAINS TO BE SEEN AS THE LOW LEVEL JET WILL BE INCREASING FROM THE SSW. FOR NOW WE WILL FAVOR A BLENDED APPROACH TO THE MAV/MET MOS. AS FOR PRECIP CHANCES...WE WILL REDUCE THE POPS FROM THE PREVIOUS FORECAST DUE TO THE SLOWER ARRIVAL TIME BUT STILL KEEP THE MENTION OF THUNDER. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A DYNAMIC STORM SYSTEM WILL BE APPROACHING AT THE START OF THE EXTENDED PERIOD. A LARGE CLOSED LOW WILL BE MOVING ACROSS THE OHIO VALLEY/EASTERN GREAT LAKES WITH A STRONG COLD FRONT AT THE SURFACE. AHEAD OF THIS BOUNDARY...A STRONG SOUTHERLY LOW LEVEL JET WILL TRANSPORT PLENTY OF MOISTURE /SOME OF WHICH WAS ASSOCIATED WITH THE REMAINS OF TC KAREN...WHICH WILL ALREADY HAVE BEEN ABSORBED INTO THE FRONTAL ZONE ACROSS THE SOUTHEAST/ TOWARDS THE REGION. THE 00Z GEFS SHOWS PWAT VALUES 2-3 STD ABOVE NORMAL ACROSS THE REGION FOR MON NIGHT INTO TUESDAY. THE MODELS CONTINUE TO SHOW PLENTY OF DISAGREEMENT WITH THE TIMING OF THIS FRONT. THE ECMWF DOESN/T CLOSE THE UPPER LOW OFF...AND A RESULT...IS MUCH QUICKER WITH THE BOUNDARY. WE WILL FAVOR THE SLOWER 00Z GFS SOLUTION...WHICH IS ALSO BETTER IN LINE WITH THE 00Z GGEM AND 00Z GEFS. AS A RESULT...MONDAY NIGHT MAY START OFF VERY MILD AND MUGGY WITH TEMPS IN THE 60S AND ONLY SCT RAIN SHOWERS...AND STEADY PRECIP MAY NOT ARRIVE UNTIL VERY LATE AT NIGHT OR UNTIL DURING THE DAY TUESDAY. TEMPS WILL STILL BE MILD ON TUESDAY...WITH UPPER 60S TO LOW 70S ACROSS THE REGION. A LINE OF SHOWERS ALONG/JUST AHEAD OF THE FRONT LOOK TO MOVE THROUGH SOMETIME ON TUESDAY. THE RAIN MAY BRIEFLY FALL HEAVY AT TIMES. WE WILL INCLUDE A SLIGHT CHC FOR THUNDER...BUT MEAGER INSTABILITY LEVELS SHOULD KEEP THUNDER FROM BEING MORE WIDESPREAD. MOST AREAS WILL SEE AROUND AN INCH OF RAINFALL...WHICH IS ACTUALLY NEEDED DUE TO THE RECENT DRY STRETCH. FLOODING ISSUES OUTSIDE LOW LYING/URBAN/POOR DRAINAGE AREAS AREN/T ANTICIPATED DUE TO THE DRY ANTECEDENT CONDITIONS AND HIGH FFG. BEHIND THE FRONT...STEADY RAIN WILL MOVE OFF TO THE EAST AND END...AND TEMPS AND HUMIDITY LEVELS WILL START TO FALL OFF. THE THREAT FOR PRECIP WON/T BE ENTIRELY GONE...AS THE UPPER LOW LOOKS TO PASS OVER THE REGION...SO THE THREAT FOR RAIN SHOWERS WILL CONTINUE FOR WED/THURS...MAINLY ACROSS THE HIGH TERRAIN AND NORTHERN AREAS. TEMPS WILL BE COOLER FOR TUES NIGHT BEHIND THE FRONT WITH 40S AND 50S. DAYTIME TEMPS ON WED/THURS WILL BE A BIT COOLER THAN RECENT DAYS...BUT STILL ABOVE NORMAL...WITH MID 60S FOR VALLEY AREAS. OVERNIGHT LOWS WED AND THURS NIGHTS WILL MAINLY BE IN THE 40S. ONCE THE UPPER LOW EXITS...A STRONG RIDGE WILL ESTABLISH ITSELF ALONG THE EASTERN SEABOARD...ALLOWING FOR EVEN MILDER AIR TO RETURN TO THE REGION. AN EXTENDED PERIOD OF DRY WEATHER LOOKS TO BE IN PLACE FROM THURSDAY NIGHT INTO MUCH OF THE WEEKEND...WITH ABOVE NORMAL WARMTH. DAYTIME TEMPS MAY RETURN TO NEAR 70 FOR FRI/SAT...WHICH IS ABOUT 10 DEGREES ABOVE NORMAL FOR MID OCT. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... FLYING CONDITIONS LOOK TO STAY MVFR FOR KALB/KGFL FOR MUCH OF THE MORNING WITH LOTS OF LINGERING LOW CLOUDS AS A STALLED OUT FRONTAL BOUNDARY WILL CONTINUE TO BE DRAPED OVER THE REGION. KPOU/KPSF MAY CONTINUE TO SEE A FEW MORE HOURS OF IFR CIGS BEFORE CIGS RISE TO MVFR CONDITIONS BY MID TO LATE MORNING. THERE MAY BE A BRIEF PERIOD OF IMPROVEMENT DURING AFTERNOON WITH VFR CONDITIONS POSSIBLE AT KGFL/KALB/KPOU. SOME SCT RAIN SHOWERS MAY AFFECT THE REGION WITH LIGHT AND VARIABLE SFC WINDS DURING THE AFTN HOURS AS WELL. ALL SITES LOOK TO BE BACK IN MVFR CONDITIONS FOR LOW CIGS BY THIS EVENING WITH CALM WINDS AND POSSIBLE RAIN SHOWERS AS THE SLOW MOVING FRONTAL BOUNDARY REMAINS NEARLY STATIONARY OVER THE AREA. IFR CONDITIONS FOR LOW CIGS MAY BE POSSIBLE LATE TONIGHT AS WELL...BUT CONFIDENCE IN THIS IS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. OUTLOOK... SUNDAY NIGHT-MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. MONDAY NIGHT-TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... LOW LEVEL MOISTURE WILL REMAIN RATHER HIGH ALONG WITH THE INCREASE THREAT FOR MORE SHOWERS. WINDS WILL BE RATHER LIGHT WITH A TENDENCY FROM THE NORTHERLY DIRECTION THROUGH TONIGHT AT SPEEDS LESS THAN 10 MPH. FIRE WEATHER CONCERNS WILL BE AT A MINIMUM. && .HYDROLOGY... NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS FOR EARLY OCTOBER. RAINFALL FORECASTS WILL RANGE FROM ONE QUARTER TO ONE HALF OF AN INCH BASIN AVERAGE NORTH AND WEST OF THE CAPITAL DISTRICT WITH ONE TENTH TO ONE QUARTER OF AN INCH FROM THE CAPITAL DISTRICT TO POINTS EAST AND SOUTH. THESE VALUES WILL BE SLIGHTLY HIGHER ACROSS THE HIGHER TERRAIN BUT LIKELY HAVE LITTLE IMPACT TO THE RIVERS WITH SLIGHT RISES EXPECTED. MAIN CHALLENGE WILL BE THE INCREASING MOISTURE PROFILES HEADING INTO MONDAY. MOISTURE FROM WHAT IS LEFT OF TS KAREN MAY BECOME ABSORBED WITHIN THE FRONTAL SYSTEM AS IT APPROACHES LATE MONDAY. RAINFALL AMOUNTS UP TO AND OVER ONE INCH ARE POSSIBLE. WITHIN BANK RIVER RISES ARE EXPECTED WITH POSSIBLE ISSUES FROM FALLEN LEAFS BLOCKING STORM DRAINS TO RESULT IN PONDING WATER. PLEASE REFER TO THE LATEST TROPICAL GUIDANCE FROM THE NATIONAL HURRICANE CENTER. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...FRUGIS FIRE WEATHER...BGM/WASULA HYDROLOGY...BGM/WASULA FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
519 PM CDT SAT OCT 5 2013 .UPDATE... 453 PM CDT ONE CLUSTER OF SEVERE STORMS CONTINUES TO MOVE ACROSS NORTHERN COOK COUNTY AND OUT OVER LAKE MICHIGAN AT 450 PM CDT WITH WEAKER THOUGH STILL INTENSE STORMS SOUTHWARD INTO KANKAKEE COUNTY. SURFACE OBS SHOW AN AREA OF LOW LEVEL CONVERGENCE WHICH HAS DEVELOPED FROM EASTERN WILL OR CENTRAL KANKAKEE COUNTY SOUTHWESTWARD TOWARD BLOOMINGTON AND LINCOLN. ANOTHER SHORTWAVE IS MOVING NORTHEAST ACROSS WESTERN IL WITH AN AREA OF RAIN SHOWERS CLOSELY TIED TO IT APPROACHING LACON...PEORIA AND SPRINGFIELD. RADAR MOSAIC ALSO SHOWS SOME SPOTTY ECHOES DEVELOPING ALONG THE AFOREMENTIONED CONVERGENCE/TROUGH...LIKELY BEING AIDED BY THE APPROACHING WAVE. EXPECT THAT DEVELOPMENT WILL CONTINUE ALONG THE TROUGH FROM GARY TO KANKAKEE TO PONTIAC AND MOVE EAST-NORTHEAST OVER THE NEXT FEW HOURS. RAIN COOLED AIR IS TO THE SOUTH AND EAST OF THIS AREA WITH TEMPS IN THE 60S BUT MUCH OF THE SOUTHEAST CWA ITSELF HAS REMAINED NORTH OF THE RAIN ACTIVITY SO INSTABILITY IS STILL SUFFICIENT. LATEST RAP ANALYSIS SHOWS THE EFFECTIVE SHEAR HAS INCREASED INTO THE 40 KT RANGE. THEREFORE THE SEVERE THREAT WILL CONTINUE AND LIKELY BE FOCUSED ALONG AND EAST OF THE GARY TO KANKAKEE TO PONTIAC LINE WITH A SHORTER TERM THREAT ALSO CONTINUING ACROSS EASTERN LAKE COUNTY IL AND ADJACENT LAKE MICHIGAN WATERS AS EXISTING STORM CLUSTER MOVES OFFSHORE. HEAVY RAINFALL WILL CONTINUE WITH ANY STORMS WITH REPORTS OF 1 TO 1.5 INCHES OF RAIN IN LESS THAN AN HOURS TIME. COVERAGE MAY STILL BE FAIRLY LOCALIZED...ESPECIALLY WITH THE FAIRLY NARROW LINEAR STRUCTURE OF NEWLY DEVELOPING STORMS. AREAS TO THE NORTH AND WEST OF THE AREAS OUTLINED ABOVE WILL LIKELY SEE ANOTHER BAND OF LIGHTER RAINFALL AND POSSIBLY SOME EMBEDDED THUNDER ARRIVE FOR THE EARLY EVENING BASED ON THE MOVEMENT OF CURRENT ACTIVITY TOWARDS PEORIA AND SPRINGFIELD. THE ADDITIONAL SHORTWAVES NOTED IN THE EARLY AFTERNOON DISCUSSION BELOW WILL ALSO BRING ADDITIONAL CHANCES FOR ADDITIONAL SHOWERS AND POSSIBLY A FEW STORMS INTO THE OVERNIGHT...WITH THE WESTERN EDGE OF THE COVERAGE GRADUALLY SHIFTING EAST WITH EACH WAVE. THE THUNDER THREAT WILL DIMINISH OVERALL THROUGH THE EVENING AND END ACROSS THE WESTERN CWA INTO THE OVERNIGHT. MDB //PREV DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * SSE WINDS SLOWLY BECOMING SOUTHWEST BY LATE THIS EVENING. * SCT -SHRA/-TSRA REMAINS POSSIBLE AROUND THE TERMINALS THROUGH 00Z...WITH MVFR CEILINGS IN THIS -TSRA. RODRIGUEZ //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. * MEDIUM HIGH CONFIDENCE WITH -SHRA/-TSRA TRENDS. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
458 PM CDT SAT OCT 5 2013 .UPDATE... 453 PM CDT ONE CLUSTER OF SEVERE STORMS CONTINUES TO MOVE ACROSS NORTHERN COOK COUNTY AND OUT OVER LAKE MICHIGAN AT 450 PM CDT WITH WEAKER THOUGH STILL INTENSE STORMS SOUTHWARD INTO KANKAKEE COUNTY. SURFACE OBS SHOW AN AREA OF LOW LEVEL CONVERGENCE WHICH HAS DEVELOPED FROM EASTERN WILL OR CENTRAL KANKAKEE COUNTY SOUTHWESTWARD TOWARD BLOOMINGTON AND LINCOLN. ANOTHER SHORTWAVE IS MOVING NORTHEAST ACROSS WESTERN IL WITH AN AREA OF RAIN SHOWERS CLOSELY TIED TO IT APPROACHING LACON...PEORIA AND SPRINGFIELD. RADAR MOSAIC ALSO SHOWS SOME SPOTTY ECHOES DEVELOPING ALONG THE AFOREMENTIONED CONVERGENCE/TROUGH...LIKELY BEING AIDED BY THE APPROACHING WAVE. EXPECT THAT DEVELOPMENT WILL CONTINUE ALONG THE TROUGH FROM GARY TO KANKAKEE TO PONTIAC AND MOVE EAST-NORTHEAST OVER THE NEXT FEW HOURS. RAIN COOLED AIR IS TO THE SOUTH AND EAST OF THIS AREA WITH TEMPS IN THE 60S BUT MUCH OF THE SOUTHEAST CWA ITSELF HAS REMAINED NORTH OF THE RAIN ACTIVITY SO INSTABILITY IS STILL SUFFICIENT. LATEST RAP ANALYSIS SHOWS THE EFFECTIVE SHEAR HAS INCREASED INTO THE 40 KT RANGE. THEREFORE THE SEVERE THREAT WILL CONTINUE AND LIKELY BE FOCUSED ALONG AND EAST OF THE GARY TO KANKAKEE TO PONTIAC LINE WITH A SHORTER TERM THREAT ALSO CONTINUING ACROSS EASTERN LAKE COUNTY IL AND ADJACENT LAKE MICHIGAN WATERS AS EXISTING STORM CLUSTER MOVES OFFSHORE. HEAVY RAINFALL WILL CONTINUE WITH ANY STORMS WITH REPORTS OF 1 TO 1.5 INCHES OF RAIN IN LESS THAN AN HOURS TIME. COVERAGE MAY STILL BE FAIRLY LOCALIZED...ESPECIALLY WITH THE FAIRLY NARROW LINEAR STRUCTURE OF NEWLY DEVELOPING STORMS. AREAS TO THE NORTH AND WEST OF THE AREAS OUTLINED ABOVE WILL LIKELY SEE ANOTHER BAND OF LIGHTER RAINFALL AND POSSIBLY SOME EMBEDDED THUNDER ARRIVE FOR THE EARLY EVENING BASED ON THE MOVEMENT OF CURRENT ACTIVITY TOWARDS PEORIA AND SPRINGFIELD. THE ADDITIONAL SHORTWAVES NOTED IN THE EARLY AFTERNOON DISCUSSION BELOW WILL ALSO BRING ADDITIONAL CHANCES FOR ADDITIONAL SHOWERS AND POSSIBLY A FEW STORMS INTO THE OVERNIGHT...WITH THE WESTERN EDGE OF THE COVERAGE GRADUALLY SHIFTING EAST WITH EACH WAVE. THE THUNDER THREAT WILL DIMINISH OVERALL THROUGH THE EVENING AND END ACROSS THE WESTERN CWA INTO THE OVERNIGHT. MDB //PREV DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SOUTH WINDS ARND 10 KT. GUSTS ARND 15KT THIS AFTN AT MDW. * SCATTERED THUNDERSTORMS EXPECTED THRU 23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN THUNDERSTORM FORECAST. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
247 PM CDT SAT OCT 5 2013 .DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SOUTH WINDS ARND 10 KT. GUSTS ARND 15KT THIS AFTN AT MDW. * SCATTERED THUNDERSTORMS EXPECTED THRU 23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN THUNDERSTORM FORECAST. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
216 PM CDT SAT OCT 5 2013 .DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SOUTH WINDS ARND 10 KT WITH GUSTS ARND 15KT THIS AFTN. * SCATTERED THUNDERSTORMS EXPECTED AFT 19Z WITH MORE WIDESPREAD STORMS EXPECTED 20Z-23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN THUNDERSTORM TRENDS...MEDIUM-HIGH CONFIDENCE IN TIMING. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
322 AM CDT SAT OCT 5 2013 .DISCUSSION... 322 AM...PRIMARY FORECAST CONCERN/CHALLENGE IS POTENTIAL FOR SEVERE WEATHER INTO THIS EVENING. FRONTAL BOUNDARY HAS BEEN SLOWLY LIFTING NORTH ACROSS NORTHERN IL WITH SOUTHERLY WINDS REACHING A RFD/ORD LINE. WHILE VISIBILITIES HAVE REMAINED GENERALLY IN THE 1-3SM RANGE NEAR THE FRONT...ACROSS FAR NORTHEAST IL SATELLITE IMAGERY SUGGESTS FOG IS RATHER THICK OVER NORTHERN SECTIONS OF LAKE AND MCHENRY COUNTIES WITH UGN REPORTING 1/4SM FOR THE PAST FEW HRS. WHILE THIS WILL LIKELY BE SHORT-LIVED...OPTED TO ISSUE A DENSE FOG ADVISORY FOR THESE TWO COUNTIES THROUGH 8AM. AS WINDS TURN SOUTHERLY...VISIBILITIES WILL IMPROVE. SOUTH OF THE FRONT...FAIRLY IMPRESSIVE AIRMASS THIS FAR NORTH FOR EARLY OCTOBER WITH DEWPOINTS IN THE UPPER 60S AND MOISTURE IS EXPECTED TO POOL THIS MORNING WITH PERHAPS LOWER 70 DEWPOINTS ACROSS MUCH OF THE AREA. UPSTREAM CLOUD COVER IS MOSTLY MID/HIGH CLOUDS THAT WILL LIKELY THIN THROUGH MID MORNING...SO APPEARS MUCH OF THIS MORNING WILL BE MOSTLY SUNNY/PARTLY CLOUDY. THIS SHOULD AID TEMPERATURES RISING INTO THE LOWER 80S ACROSS THE SOUTHEAST HALF OF THE AREA AND WITH SUCH A MOIST AIRMASS IN PLACE...ONCE HEATING BEGINS...POSSIBLE FOR ISOLATED THUNDERSTORMS THIS MORNING. BULK OF THE ACTIVITY HOWEVER APPEARS TO HOLD OFF UNTIL THIS AFTERNOON...BOTH FROM INCREASING DIURNALLY DRIVEN STORMS BUT ALSO AS A SHORTWAVE LIFTS NORTHEAST ACROSS NORTH CENTRAL ILLINOIS THIS AFTERNOON INTO THIS EVENING...AHEAD OF THE APPROACHING COLD FRONT. WITH THUNDERSTORMS SPREADING EAST THIS EVENING BUT SLOWING. OVERALL CONFIDENCE REGARDING THIS SCENARIO IS SOMEWHAT LOW IN ADDITION TO THE POTENTIAL FOR SEVERE WEATHER. THE MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS GUSTS BUT LACK OF STRONG SHEAR ALOFT WOULD SUGGEST THESE WOULD BE MORE ISOLATED...RATHER THEN A LINE OF STRONG/SEVERE STORMS. IN ADDITION...THE VERY MOIST LOW LEVELS WILL YIELD LOW LCL HEIGHTS AND MODELS ARE IN FAIR AGREEMENT WITH SURFACE WINDS BACKING SOME THIS AFTERNOON. THUS INDIVIDUAL CELLS THAT FORM AWAY FROM CLUSTERS OR LINES OF CONVECTION WILL HAVE SOME POTENTIAL TO PRODUCE A TORNADO. FORECAST PRECIPITABLE WATER VALUES OF 1.5 INCHES OR HIGHER WILL LEAD TO LOCALLY VERY HEAVY RAIN AND WITH LITTLE CHANGE TO STORM MOTION...GENERALLY SOUTHWEST TO NORTHEAST...ANY TRAINING OF STORMS COULD EASILY CAUSE FLOODING CONCERNS. ACTIVITY WILL SLOWLY SHIFT EAST LATE TONIGHT INTO SUNDAY MORNING AND HAVE INCLUDED CHANCE POPS EAST OF I-57 INTO THE MORNING. UNCERTAINTY HAS INCREASED WITH THE ARRIVAL OF THE 00Z ECMWF WHICH IS CONSIDERABLY FASTER THAN OTHER 00Z GUIDANCE WITH THE PROGRESSION OF THE UPPER LOW EAST ACROSS THE LAKES REGION. SUNDAY WAS SHAPING UP TO BE MAINLY DRY WITH PERHAPS SOME INSTABILITY SHOWERS ARRIVING IN THE WEST BY EVENING. AND WITH THE POSSIBILITY OF SOME SUNSHINE...TEMPS PERHAPS IN THE 60S AND WHILE THAT WILL BE MUCH COLDER THAN TODAY...IT WOULD ONLY BE A FEW DEGREES BELOW NORMAL. A FASTER SHIFT EAST OF THE UPPER LOW WILL ALSO END THE SHOWER POTENTIAL MONDAY OR MONDAY EVENING...RATHER THAN TUESDAY MORNING WITH THE SLOWER SOLUTIONS. CHANGES TO THE SUNDAY-TUESDAY TIME PERIOD CAN BE EXPECTED DEPENDING ON THE SPEED OF THE UPPER LOW. HOWEVER...THE WARMING TREND STILL LOOKS ON TRACK...PERHAPS JUST DELAYED BY A DAY OR SO WITH HIGHS BACK INTO THE 70S BY WEDNESDAY AND THURSDAY. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOWERING VISIBILITY AND CIGS INTO IFR CATEGORY INTO OVERNIGHT. * NORTHEAST WINDS BECOMING EAST THEN SOUTHEAST TONIGHT WITH SPEEDS MOST OF TIME BELOW 10 KT. * SMALL CHANCE OF TSRA SAT MORNING GRADUALLY INCREASING INTO MID- AFTERNOON. * THUNDERSTORMS LIKELY 22Z-00Z SOME OF WHICH COULD BE STRONG. BEACHLER //DISCUSSION...UPDATED 06Z... VERY CHALLENGEING AVIATION CONDITIONS ARE IN STORE FOR THE NEXT 24 HOURS ACROSS THE REGION...ESPECIALLY OVER NORTHERN IL/NORTHWEST IN. A STALLED FRONTAL BOUNDARY WAS ORIENTED ACROSS NORTHERN IL...WHICH HAS RESULTED IN LIGHT WINDS TO AT TIMES CALM FOR DPA/ORD/MDW/GYY. IN ADDITION VERY MOIST AIR WAS OVER THESE AIRFIELDS AND HAS RESULTED IN VSBYS BEING REDUCED. IT APPEARS ORD SHOULD ONLY REDUCE TO ARND 3-4SM OVERNIGHT...HOWEVER ELSEWHERE MDW/GYY/DPA/RFD WILL LIKELY SEE VSBYS DOWN BTWN 1/2SM AT RFD/DPA TO 2-3SM AT GYY/MDW. IR IMAGERY INDICATED SOME IFR CIGS WERE DEVELOPING OVER FAR NORTHWEST IL WHICH HAS BROUGHT CIGS DOWN AT RFD...AND IT IS POSSIBLE CIGS COULD DROP TO ARND 200-300FT AGL BEFORE DAYBREKA THEN SLOWLY IMPROVE AFT DAYBREAK. THEN THE FOCUS TURNS TOWARDS CONVECTIVE TIMING/PLACEMENT LATER TODAY. AFTER SUNRISE VSBYS SHUD BE SLOW TO IMPROVE WITH JUST A CIRRUS SHIELD EXPECTED OVERHEAD TO START THE DAY. THE COLD FRONT WILL BE WELL WEST OF THE REGION...HOWEVER STEADILY PIVOTING EAST TOWARDS NORTHERN IL AIRFIELDS. GUIDANCE CONTINUES TO INDICATE WINDS BY MID MORNING WILL BECOME SOUTHERLY ARND 10KT AND OCCASIONAL GUSTS TO THE MID-TEENS ARE LIKELY. CLOUDS WILL THICKEN BY MIDDAY WITH A DECK ARND 3-4KFT AGL. WITH CONSIDERABLE ELEMENTS SUGGESTING CONVECTION WILL BE FIRING ARND 18-19Z...IT IS LIKELY THAT THE BEST CHC FOR CONVECTION WILL BE ARND 19Z-00Z...AND THE BETTER COVERAGE WILL FALL WITHIN A 22-00Z TIMEFRAME. WINDS WILL SLOWLY TURN TO THE 240-260 DEG RANGE FRONTAL PASSAGE...WITH RAIN/THUNDER SLOWLY ENDING AFT 03-06Z SUN. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN STABLE/SLIGHTLY LOWERING TREND OF CIG...MEDIUM CONFIDENCE ON VISIBILITY. MEDIUM CONFIDENCE ON HOW LOW CIG AND VISIBILITY WILL FALL. * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE ON TSRA TIMING OF 21Z-02Z. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...VFR DURING THE DAY WITH MVFR CIGS AND CHC SHRA DURING THE NIGHT. MONDAY...CHC OF MVFR AND SLT CHC OF SHRA DURING THE MORNING. TUESDAY-THURSDAY...MAINLY VFR. MTF && .MARINE... 341 PM CDT A TROUGH OF LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY ARE SITUATED ACROSS THE UPPER MISSISSIPPI VALLEY EAST ACROSS TO THE SOUTHERN GREAT LAKES REGION...WITH THESE FEATURES STEMMING FROM AN AREA OF LOW PRESSURE SITUATED OVER THE CENTRAL PLAINS. ITS THESE FEATURES THAT ARE PROVIDING...AND WILL CONTINUE TO PROVIDE DRASTICALLY VARYING CONDITIONS ACROSS THE ENTIRE LAKE. A LIGHTER WIND FIELD IS CURRENTLY PRESENT OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT IS RELAXED...BUT WITH SPEEDS INCREASING TO 15 TO 25 KT FOR THE FAR NORTHERN PORTIONS OF THE LAKE. THIS BOUNDARY WILL LIFT BACK NORTH ACROSS THE LAKE TONIGHT INTO SATURDAY WHILE THIS LOW PRESSURE SYSTEM SLOWLY TRACKS NORTHEAST TOWARDS THE MISSISSIPPI VALLEY. AS THIS OCCURS...EXPECT A GRADUAL TRANSITION TO THE EAST SOUTHEAST WITH SPEEDS INCREASING ACROSS THE ENTIRE LAKE. EXPECT THE HIGHEST SPEEDS OF 30KT TO BE OBSERVED ACROSS THE NORTH...WITH THESE EASTERLY WINDS/SPEEDS LIKELY PERSISTING INTO EARLY SATURDAY NIGHT. EXPECT THIS LOW TO THEN CONTINUE NORTHEAST AND REACH THE CENTRAL GREAT LAKES LATE SATURDAY NIGHT INTO SUNDAY...AND THEN CONTINUE EAST TOWARDS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. AS THIS OCCURS...EXPECT SPEEDS TO DIMINISH WHILE BECOMING MORE SOUTHERLY ON SUNDAY AND THEN WEST/NORTHWEST INTO MONDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ005-ILZ006 UNTIL 8 AM SATURDAY. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 301 AM CDT Sat Oct 5 2013 .DISCUSSION... ISSUED 301 AM CDT Sat Oct 5 2013 After a stormy day across central Illinois today, much cooler weather will arrive for early next week. 07z/2am surface map shows 1000mb low centered over South Dakota, with cold front extending southeastward into Iowa/Missouri. Very warm and humid airmass remains in place ahead of the front, with temps in the 70s and dewpoints in the upper 60s. Meanwhile, sharply colder conditions are noted further west behind the boundary where readings are only in the 30s across the Dakotas and Nebraska. SHORT TERM...Today through Monday Deep upper-level low currently spinning over South Dakota will be the main weather-maker across the region for the next couple of days. As this system slowly wobbles eastward, it will push a strong cold front through central Illinois later today into tonight. 00z models have slowed eastward progression of the front just a bit, bringing it into the Illinois River Valley by around 21z/4pm. Given occluded nature of system, this slower trend seems reasonable. As such, have lowered POPs across the western KILX CWA into the chance category during the morning hours, opting to hit POPs hardest during the afternoon and evening as best forcing arrives. The front will have plenty of moisture to work with as forecast soundings show precipitable water values greater than 1.50. The airmass will also be moderately unstable, with CAPE values ranging from 1500 to 2000J/kg. Main mitigating factor for widespread severe weather will be weak wind fields/shear. While instability axis will be positioned across Illinois and the Ohio River Valley this afternoon, strongest wind shear will be displaced well to the west across Iowa and Missouri. With these two key severe weather parameters not coinciding with one another, am not expecting a major severe event today. Thunderstorms will increase in areal coverage during the afternoon, with perhaps a few of them producing severe wind gusts. Outside of thunderstorms, it will be another very warm day with highs ranging from the middle 70s west to the lower 80s east. Based on expected speed of front, temps will likely drop into the 60s along/west of the Illinois River late this afternoon after FROPA. Due to slower frontal movement, have increased POPs tonight. Will carry likely to categorical POPs along/east of the Illinois River during the evening, with best rain chances shifting to the I-57 corridor and eastward after midnight. Once front passes, skies will clear across the Illinois River Valley late tonight. Low temperatures will range from the lower 40s far west around Galesburg and Rushville, to the upper 50s near the Indiana border. Will linger some shower chances along/east of I-57 through Sunday morning, as front slowly progresses eastward across Indiana. Mid-level dry slot behind front and immediately ahead of slowly approaching upper low will allow skies to be partly to mostly sunny across the central and western CWA Sunday morning before clouds begin to increase from the west by late in the day. Given slow movement of system, have pulled back POPs from previous forecast to feature only a slight chance for showers across the far west Sunday afternoon. Cold core upper low will track overhead Sunday night into Monday, creating a chilly and showery weather pattern. NAM/GFS/GEM are all in excellent agreement with the position of the 500mb closed low over Illinois by 12z Mon. Meanwhile, the latest run of the ECMWF has made a drastic shift from its previous solution, now placing the low over Michigan Monday morning. Will reject the ECMWF in favor of the model consensus here. As a result, have added low POPs for showers both Sunday night and Monday. Have also lowered highs considerably for Monday, with readings only reaching the lower 60s. LONG TERM...Tuesday through Friday Once upper low lifts further northeast, upper heights will once again be on the rise across the central and eastern CONUS next week. 850mb temps respond accordingly, with readings back into the 14 to 16c range by Thursday and Friday. This will support highs well into the 70s and perhaps the lower 80s by the end of the week. Barnes && .AVIATION... ISSUED 1151 PM CDT Fri Oct 4 2013 Latest runs of the high resolution models and the 00z NAM/GFS indicate that the aviation forecast for central IL TAF sites needs few changes from the previous issuance. Still looking for light fog/mist to form toward early morning, although it is looking less likely that a stratus ceiling will develop. Plenty of high and mid clouds from upstream convective debris will move into central and eastern Illinois overnight. Radar trends, as well as the latest HRRR and RAP forecasts, indicating that convective remnants to approach central Illinois shortly after daybreak ahead of the cold front. Plenty of moisture, instability and increasing low/mid level wind shear will be present for t-storms to redevelop in a linear fashion by early afternoon. Maintained the predominant thunderstorm forecast to account for this expected development and movement of a line of storms. The higher resolution models were also indicating that the front will move a bit slower than previously forecast. Thus, the 06z TAFs will extend the thunderstorms a couple of hours from the previous forecast, and also hold off the frontal passage/wind shift until late afternoon- evening. Miller && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 AM CDT SAT OCT 5 2013 .DISCUSSION... 804 PM CDT THIS EVENING...WARM FRONT STRETCHES FROM NEAR DBQ ESE TO JOT...THEN EAST TO VPZ. TEMPERATURES CONTINUE TO RUN IN THE MID TO UPPER 70S SOUTH OF THE FRONT...WITH DEWPOINTS INTO THE MID TO UPPER 60S. NORTH OF THE BOUNDARY...TEMPERATURES QUICKLY TAPER INTO THE MID 60S...WITH LOW DEW POINT DEPRESSIONS. FOG/LOW STRATUS ALREADY STARTING TO DEVELOP ACROSS THESE AREAS...AND SHOULD CONTINUE TO EXPAND OVERNIGHT. REMOVED PRECIP MENTION OVERNIGHT FOR ALL BUT THE NORTHERN TIER OF COUNTIES. LAST VISIBLE SATELLITE IMAGES BEFORE SUNSET SHOWED CU FIELD QUICKLY DISSIPATING...AND THE MAIN IMPETUS FOR ANY PRECIP OVERNIGHT IS NEAR THE IL/WI STATE LINE WHERE THE BEST FOCUSED ISENTROPIC ASCENT IS NOTED. FORECAST OTHERWISE ON TRACK WITH ONLY MINOR TWEAKS TO THE HOURLY TRENDS. DEUBELBEISS //PREV DISCUSSION... 240 PM FOR THE REMAINDER OF THE AFTERNOON THROUGH SATURDAY...THE MAIN CONCERN WILL BE SEVERE WEATHER POTENTIAL...WITH A SECONDARY CONCERN FOR TEMPERATURES. EARLY THIS AFTERNOON...CONVECTIVE ACTIVITY IS FOCUSING ON THE NOSE OF A STRONG LOW LEVEL JET POINTING INTO NRN IL...WHICH IS ENHANCING THE ISENTROPIC LIFT ALREADY IN PLACE AS WARM MOIST AIR CONTINUES TO STREAM INTO THE REGION. A SECONDARY FOCUS OF CONVECTIVE ACTIVITY IS A SFC TROUGH/SECONDARY WARM FRONT EXTENDING FROM NRN MO...THROUGH NRN IL AND NRN INDIANA. LATEST RADAR IMAGERY SHOWS THE WARM ADVECTION CONVECTION ALREADY INTO NWRN IL AND WITH COPIOUS AMOUNTS OF HEAT...TEMPS IN THE UPPERS 70S-LOW 80S...MOISTURE...DEWPOINTS IN THE UPPER 60S TO LOWERS 70S...AND INSTABILITY...MIXED LAYER CAPE OF 1500-2000 J/KG...EXPLOSIVE CONVECTION IS QUITE POSSIBLE WHERE ALL ELEMENTS LINE UP JUST RIGHT. WITH THE LOW LEVEL JET OF 30KT+ OVER THE AREA...STRONGER WINDS CAN CERTAINLY MIX DOWN TO THE SURFACE. THE ONE QUESTION MARK AT THIS TIME IS THE CLOUD COVER. LATEST SATELLITE IMAGERY SHOWS DENSE OVC OVER NRN IL...WITH MORE CONVECTIVELY DRIVEN CU/TOWERING CU SOUTH OF THE I-80 CORRIDOR. OF PARTICULAR CONCERN IS THE SECONDARY WARM FRONT...WHICH LIES IN THE AREA OF GREATER SFC INSOLATION SOUTH OF I-80. THE 12Z ILX SOUNDING INDICATES AT LEAST SOME VEERING OF WINDS THROUGH THE LOWER LEVELS WHICH WOULD HELP ADD SOME ROTATIONAL ASPECT TO STORMS...WHICH IN TURN COULD ADD A LARGE HAIL OR TORNADIC POTENTIAL TO THE STRONG WIND THREAT. ON TOP OF ALL OF THIS WILL BE A HEAVY RAINFALL POTENTIAL. THE 12Z KDVN SOUNDING INDICATES PWAT OF 1.4 INCHES...SO DEEP LAYER MOISTURE IS ALREADY IN PLACE. THE VARIOUS MODEL FORECAST PWATS INDICATE THAT A CORRIDOR OF EXTREME DEEP LAYER MOISTURE POOLING IN A CORRIDOR FROM SWRN WISCONSIN TO NERN KANSAS. WITH TIME AND PROGRESSION OF THE PATTERN...EXPECT THAT PWATS WILL ONLY INCREASE OVER THE LOCAL AREA THROUGH THE NEXT 36HRS. THE KDVN PWAT CLIMATOLOGY INDICATES THAT FOR OCTOBER...2 STANDARD DEVIATIONS FROM NORMAL IS 1.6 INCHES AND THE 99TH PERCENTILE PWAT IS 1.9 INCHES. THE LATEST MODEL RUNS SHOW PWAT INCREASING TO IN EXCESS OF 1.5 INCHES IN THE ENVIRONMENT AHEAD OF THE APPROACHING COLD FRONT. SO...FOR THE SEVERE WEATHER THREAT...TIMING AND COVERAGE ARE THE BIG QUESTIONS. ANTICIPATE THAT THE GREATEST SEVERE WEATHER THREAT WILL BE WITH THE COLD FRONT DUE TO THE GREATER SFC FORCING WHICH WILL LINE UP WITH THE FAVORABLE UPPER DYNAMICS WITH THE UPPER TROUGH. HOWEVER...THERE WILL STILL BE A MORE ISOLATED SEVERE WEATHER THREAT ACROSS THE LOCAL AREA SIMPLY DUE TO THE UNSEASONABLY STRONG LOWER LEVEL THERMODYNAMICS AND EXTREME DEEP LAYER MOISTURE. ALONG WITH THE SEVERE WEATHER THREAT...HEAVY RAINFALL AND LOCALIZED FLOODING WILL BE A CONCERN. THE PRIMARY LOCATION FOR POSSIBLE FLOODING WILL BE ALONG THE SECONDARY WARM FRONT AS RADAR TRENDS INDICATE THAT THE BOUNDARY ITSELF IS QUASISTATIONARY WHILE INDIVIDUAL CELLS TRACK TO THE EAST. THE CURRENT CONVECTIVE ACTIVITY ALONG THIS BOUNDARY IS CURRENTLY OVER NRN INDIANA...BUT RADAR SHOWS A FINE-LINE WEST INTO NERN IL. IF CONVECTION FILLS IN ALONG THE BOUNDARY AND IT REMAINS QUASISTATIONARY OR AT LEAST SLOWLY PROGRESSIVE...LOCALIZED FLOODING WILL BECOME AN INCREASING CONCERN. FOR TIMING OF THE PROGRESSION OF THE COLD FRONT...THE VARIOUS MODELS HAVE CONVERGED INTO GOOD AGREEMENT ON THE PROGRESSION...CROSSING THE RIVER INTO NWRN IL BY ARND 12Z SATURDAY AND STEADILY PROGRESSING EWD TO NRN INDIANA BY LATE AFTERNOON OR EARLY EVENING. THE THUNDERSTORM THREAT SHOULD BE CONFINED TO A ZONE ALONG AND AHEAD OF THE FRONT. FOLLOWING THE FRONTAL PASSAGE...CONDITIONS SHOULD QUICKLY IMPROVE...FOR A TIME...WITH TEMPERATURES DROPPING OFF QUICKLY. TEMPERATURES WILL DROP OFF FROM HIGHS IN THE LOW TO MIDDLE 80S TODAY AND SATURDAY TO LOWS IN THE UPPER 40S TO MIDDLE 50S SUNDAY MORNING AND LOWS IN THE MIDDLE 40S BY MONDAY MORNING. HIGHS FOR SUNDAY AND MONDAY SHOULD BE IN THE LOWER TO MIDDLE 60S. THERE WILL STILL BE SOME CHANCE FOR SOME PCPN SUNDAY AND MONDAY AS THE CENTER OF THE UPPER LOW TRACKS RIGHT OVER NRN IL/IN...BUT ANY PCPN SHOULD GENERALLY BE SCT SHOWERS AND PCPN AMOUNTS GENERALLY LIGHT. FOR THE EXTENDED FORECAST PERIOD...FROM TUESDAY THROUGH FRIDAY...EXPECT A PERIOD OF SLOWLY MODERATING TEMPERATURES WITH LITTLE TO NO CHANCE OF PCPN. FOLLOWING THE PASSAGE OF THE UPPER LOW...A BUILDING UPPER LEVEL RIDGE WILL SLOWLY MOVE OUT OVER THE PLAINS AND MISSISSIPPI VALLEY AS ANOTHER DEEP UPPER LOW DROPS DOWN THE WEST COAST INTO THE DESERT SOUTHWEST. THE AMPLIFYING...BUT SLOWLY PROGRESSIVE PATTERN ALOFT WILL KEEP CONDITIONS DRY WITH ABOVE NORMAL TEMPS OVER THE LOCAL WITH HIGHS IN THE LOWER TO MIDDLE 70S AND LOWS IN THE UPPER 40S TO MIDDLE 50S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOWERING VISIBILITY AND CIGS INTO IFR CATEGORY INTO OVERNIGHT. * NORTHEAST WINDS BECOMING EAST THEN SOUTHEAST TONIGHT WITH SPEEDS MOST OF TIME BELOW 10 KT. * SMALL CHANCE OF TSRA SAT MORNING GRADUALLY INCREASING INTO MID- AFTERNOON. * THUNDERSTORMS LIKELY 22Z-00Z SOME OF WHICH COULD BE STRONG. BEACHLER //DISCUSSION...UPDATED 06Z... VERY CHALLENGEING AVIATION CONDITIONS ARE IN STORE FOR THE NEXT 24 HOURS ACROSS THE REGION...ESPECIALLY OVER NORTHERN IL/NORTHWEST IN. A STALLED FRONTAL BOUNDARY WAS ORIENTED ACROSS NORTHERN IL...WHICH HAS RESULTED IN LIGHT WINDS TO AT TIMES CALM FOR DPA/ORD/MDW/GYY. IN ADDITION VERY MOIST AIR WAS OVER THESE AIRFIELDS AND HAS RESULTED IN VSBYS BEING REDUCED. IT APPEARS ORD SHOULD ONLY REDUCE TO ARND 3-4SM OVERNIGHT...HOWEVER ELSEWHERE MDW/GYY/DPA/RFD WILL LIKELY SEE VSBYS DOWN BTWN 1/2SM AT RFD/DPA TO 2-3SM AT GYY/MDW. IR IMAGERY INDICATED SOME IFR CIGS WERE DEVELOPING OVER FAR NORTHWEST IL WHICH HAS BROUGHT CIGS DOWN AT RFD...AND IT IS POSSIBLE CIGS COULD DROP TO ARND 200-300FT AGL BEFORE DAYBREKA THEN SLOWLY IMPROVE AFT DAYBREAK. THEN THE FOCUS TURNS TOWARDS CONVECTIVE TIMING/PLACEMENT LATER TODAY. AFTER SUNRISE VSBYS SHUD BE SLOW TO IMPROVE WITH JUST A CIRRUS SHIELD EXPECTED OVERHEAD TO START THE DAY. THE COLD FRONT WILL BE WELL WEST OF THE REGION...HOWEVER STEADILY PIVOTING EAST TOWARDS NORTHERN IL AIRFIELDS. GUIDANCE CONTINUES TO INDICATE WINDS BY MID MORNING WILL BECOME SOUTHERLY ARND 10KT AND OCCASIONAL GUSTS TO THE MID-TEENS ARE LIKELY. CLOUDS WILL THICKEN BY MIDDAY WITH A DECK ARND 3-4KFT AGL. WITH CONSIDERABLE ELEMENTS SUGGESTING CONVECTION WILL BE FIRING ARND 18-19Z...IT IS LIKELY THAT THE BEST CHC FOR CONVECTION WILL BE ARND 19Z-00Z...AND THE BETTER COVERAGE WILL FALL WITHIN A 22-00Z TIMEFRAME. WINDS WILL SLOWLY TURN TO THE 240-260 DEG RANGE FRONTAL PASSAGE...WITH RAIN/THUNDER SLOWLY ENDING AFT 03-06Z SUN. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN STABLE/SLIGHTLY LOWERING TREND OF CIG...MEDIUM CONFIDENCE ON VISIBILITY. MEDIUM CONFIDENCE ON HOW LOW CIG AND VISIBILITY WILL FALL. * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE ON TSRA TIMING OF 21Z-02Z. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...VFR DURING THE DAY WITH MVFR CIGS AND CHC SHRA DURING THE NIGHT. MONDAY...CHC OF MVFR AND SLT CHC OF SHRA DURING THE MORNING. TUESDAY-THURSDAY...MAINLY VFR. MTF && .MARINE... 341 PM CDT A TROUGH OF LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY ARE SITUATED ACROSS THE UPPER MISSISSIPPI VALLEY EAST ACROSS TO THE SOUTHERN GREAT LAKES REGION...WITH THESE FEATURES STEMMING FROM AN AREA OF LOW PRESSURE SITUATED OVER THE CENTRAL PLAINS. ITS THESE FEATURES THAT ARE PROVIDING...AND WILL CONTINUE TO PROVIDE DRASTICALLY VARYING CONDITIONS ACROSS THE ENTIRE LAKE. A LIGHTER WIND FIELD IS CURRENTLY PRESENT OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT IS RELAXED...BUT WITH SPEEDS INCREASING TO 15 TO 25 KT FOR THE FAR NORTHERN PORTIONS OF THE LAKE. THIS BOUNDARY WILL LIFT BACK NORTH ACROSS THE LAKE TONIGHT INTO SATURDAY WHILE THIS LOW PRESSURE SYSTEM SLOWLY TRACKS NORTHEAST TOWARDS THE MISSISSIPPI VALLEY. AS THIS OCCURS...EXPECT A GRADUAL TRANSITION TO THE EAST SOUTHEAST WITH SPEEDS INCREASING ACROSS THE ENTIRE LAKE. EXPECT THE HIGHEST SPEEDS OF 30KT TO BE OBSERVED ACROSS THE NORTH...WITH THESE EASTERLY WINDS/SPEEDS LIKELY PERSISTING INTO EARLY SATURDAY NIGHT. EXPECT THIS LOW TO THEN CONTINUE NORTHEAST AND REACH THE CENTRAL GREAT LAKES LATE SATURDAY NIGHT INTO SUNDAY...AND THEN CONTINUE EAST TOWARDS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. AS THIS OCCURS...EXPECT SPEEDS TO DIMINISH WHILE BECOMING MORE SOUTHERLY ON SUNDAY AND THEN WEST/NORTHWEST INTO MONDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1151 PM CDT Fri Oct 4 2013 .DISCUSSION... ISSUED 850 PM CDT Fri Oct 4 2013 Updated the forecast for tonight to increase the PoPs early in southeast IL for the isolated showers and few rumbles of thunder. Also dropped the PoPs a bit in areas west of the IL River. Radar trends with the convection in Iowa and western Missouri, along with high res model solutions from the HRRR and RAP, indicate that the showers and t-storms may not impact west central IL until close to daybreak. Otherwise, the forecast low temperatures, sky cover and wind are all on track for the rest of tonight. && .AVIATION... ISSUED 1151 PM CDT Fri Oct 4 2013 Latest runs of the high resolution models and the 00z NAM/GFS indicate that the aviation forecast for central IL TAF sites needs few changes from the previous issuance. Still looking for light fog/mist to form toward early morning, although it is looking less likely that a stratus ceiling will develop. Plenty of high and mid clouds from upstream convective debris will move into central and eastern Illinois overnight. Radar trends, as well as the latest HRRR and RAP forecasts, indicating that convective remnants to approach central Illinois shortly after daybreak ahead of the cold front. Plenty of moisture, instability and increasing low/mid level wind shear will be present for t-storms to redevelop in a linear fashion by early afternoon. Maintained the predominant thunderstorm forecast to account for this expected development and movement of a line of storms. The higher resolution models were also indicating that the front will move a bit slower than previously forecast. Thus, the 06z TAFs will extend the thunderstorms a couple of hours from the previous forecast, and also hold off the frontal passage/wind shift until late afternoon- evening. Miller && .PREV DISCUSSION... ISSUED 300 PM CDT Fri Oct 4 2013 The current heat and humidity will be displaced by a chilly Canadian airmass after a strong cold front moves through on Saturday. Severe weather potential will increase as we head into Saturday afternoon, especially if sunshine is able to help destabilized the boundary layer for any portion of the day. A slight risk for severe storms has been outlined by SPC for nearly all of Illinois. The timing of the front remains in question, with a compromise used between the faster NAM/Canadian and the slower GFS/ECMWF. That basically allowed for some consistency with the going forecast. Dry air will be wrapping into the back side of the cold front, but as the occlusion process occurs, bands of moisture will trail the front and allow for a few post frontal showers to linger into Sunday and possibly even Monday. SHORT TERM...Tonight through Sunday night. A Pacific moisture connection will continue to feed into the warm sector across the nations heartland over the next 24-36 hours...as the warm front lingers in N Iowa and S Wisconsin. Localized pockets of energy will tap into that moisture to fuel isolated showers in our SE counties as well as our far NW counties into this evening. Most areas should remain dry this evening, and even overnight. We left a wide area of slight chance pops across the area after midnight, with chance PoPs in the far NW closer to the expected storm track. Tonight and early Saturday, low pressure in the western plains will lift north into eastern South Dakota before stalling during occlusion. It`s eastward progression will pick up speed as a kicker trough enters the northwest coast. The timing of the front will be key in where severe potential is maximized, mainly from the amount of sunshine for low level heating. There may be some isolated severe storms overnight west of our area as the nocturnal jet intensifies ahead of the cold front. The cold front is projected to reach the I-55 corridor by Noon or 1 pm, then slow down and reach the Indiana border mid- evening. Instability params and hodographs are pointing toward damaging winds as the main hazard in our area, with better directional shear and rotating storms farther north near the warm front and track of the low. Hail potential will increase closer to the cold front and moisture pooling and updraft strength intensify. Severe chances will linger into the evening east of I-57, but should become more isolated as the front slows down. We kept likely PoPs east of I-57 Sat eve, and near the Indiana border after midnight. Coverage of storms will likely diminish Sat night as will intensity. Some clearing behind the cold front will low temps drop into the 40s by Sunday morning west of I-55. The cold air will limit highs on Sunday to the upper 50s near GBG and mid 60s near LWV. Scattered rain will be possible across the east and north associated with cold pool-instability showers...as the upper trough lingers just west of IL. Sunday night will be coldest night of the next week, with lows in the low to mid 40s everywhere. LONG TERM...Monday through Friday. The upper vortex may still be over IL on Monday if the GFS and ECMWF verify, which would put showers across IL during the day. We left Mon dry for now, but at least sprinkles may be needed if the next couple of model runs show the slower progression. A warming trend will begin on Tue and continue through Friday. Highs should reach above normal into the mid 70s Thur/Fri. Dry conditions are expected to prevail all week, with comfortable humidity levels. The next chance of rain may hold off until the Sunday Oct 13. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
154 PM EDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 342 AM EDT SAT OCT 5 2013 A LARGE LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK. THIS LOW PRESSURE SYSTEM WILL ALSO SEND A COLD FRONT THROUGH THE AREA WITH TEMPERATURES RETURNING TO NEAR NORMAL VALUES AFTER HIGHS IN THE LOW 80S AGAIN TODAY. && .UPDATE... ISSUED AT 1125 AM EDT SAT OCT 5 2013 A COUPLE OF SMALL SCALE EMBEDDED WAVES IN SOUTHWEST UPPER FLOW HAVE RESULTED IN CLUSTERS OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL/NORTHEAST INDIANA. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OTHER SOUTHERN LAKE MICHIGAN IN CLOSER PROXIMITY TO MORE PRONOUNCED UPPER LEVEL DIFFLUENCE DOWNSTREAM OF VIGOROUS NORTHERN PLAINS UPPER TROUGH. AREAS ROUGHLY ALONG AND SOUTHEAST OF A HUNTINGTON INDIANA TO FORT WAYNE INDIANA TO DEFIANCE LINE HAVE LIKELY RECEIVED BETWEEN A HALF INCH TO AN INCH OF RAINFALL SO FAR THIS MORNING. SOME OF THESE SAME LOCATIONS ACROSS NORTHWEST OHIO HAVE ALSO RECEIVED HEAVY RAINFALL YESTERDAY. GIVEN INCREASING CONFIDENCE IN SIGNIFICANT RAINFALL LATE TONIGHT INTO SUNDAY EVENING ALONG WITH RECENT HEAVY RAIN...WILL BE ISSUING A FLASH FLOOD WATCH SHORTLY FOR FAR NORTHEAST INDIANA...PORTIONS OF SOUTH CENTRAL LOWER MICHIGAN....AND ALL OF NORTHWEST OHIO COUNTIES FROM 06Z TONIGHT TO 06Z MONDAY. IN TERMS OF CONVECTIVE POTENTIAL...15Z RUC ANALYSIS DEPICTS 1000-1500 J/KG OF 100 HPA MLCAPES ACROSS MUCH OF WESTERN HALF OF THE AREA WITH 0 TO 6 KM BULK SHEAR VALUES IN THE 25 TO 30 KNOT RANGE. DESPITE SIGNIFICANT CLOUD COVER...DEEP MOISTURE PROFILES SHOULD CONTINUE TO YIELD CAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. DEEP LAYER SHEAR TO ALSO INCREASE LATE AFTERNOON ACROSS WESTERN HALF OF THE AREA AS A 500 HPA SPEED MAX LIFTS INTO NORTHWEST INDIANA AFTER 21Z. THUS...NO CHANGE IN THINKING FROM PREVIOUS FORECAST WITH LOW/ISOLATED SEVERE THREAT ACROSS ESPECIALLY WESTERN AREAS LATE AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM EDT SAT OCT 5 2013 GRADUAL APPROACH OF IMPRESSIVE CLOSED OFF CYCLONIC GYRE EXTENDING THROUGH THE BULK OF THE TROPOSPHERE WILL BRING INCREASING CHANCES FOR RAIN THROUGH THE SHORT TERM PERIOD. SURFACE FRONTAL BOUNDARY EXTENDING INTO THE SOUTHERN GREAT LAKES WILL MOVE LITTLE THROUGH THE PERIOD WITH PERSISTENT THETA-E ADVECTION IN A LARGELY UNCAPPED ENVIRONMENT LEADING TO CONTINUED PERIODS OF CONVECTION. SMALL SCALE VORTICES IN SOUTHWEST FLOW ALOFT EMANATING FROM THE CENTRAL CONUS WILL ALSO SUPPORT INCREASING CHANCES FOR RAINFALL AS THE MAIN SYSTEM APPROACHES. OCCLUSION PROCESS IS ALREADY BEGINNING AND EARLIER NOTED SLOWING TREND HAS CONTINUED. MAIN SURFACE COLD FRONT IS NOT EXPECTED TO REACH OUR CWA UNTIL LATE TONIGHT. WILL STILL BE PLENTY OF RAIN AHEAD OF THE MAIN FRONT THOUGH. TIGHTENING LOW LEVEL MASS GRADIENT ASSOCIATED WITH APPROACHING PV ANOMALY WILL LEAD TO A STRENGTHENING OF THE LLJ AND A CORRESPONDING UPTICK IN 305K ISENTROPIC ASCENT. MOISTURE WILL CERTAINLY NOT BE LACKING EITHER. 305K MIXING RATIOS ARE ABOVE 8 G/KG AND PW VALUES ARE HOVERING AROUND 1.75 INCHES...NEAR THE 99TH PERCENTILE FOR THIS TIME OF YEAR BASED ON REGIONAL UPPER AIR CLIMATOLOGY. EXACT TIMING/PLACEMENT OF CONVECTION REMAINS HIGHLY UNCERTAIN BUT EXPECT COVERAGE TO INCREASE AS THE DAY WEARS ON GIVEN INCREASING DIURNAL INSTABILITY AND APPROACHING TROUGH. LATEST HI-RES GUIDANCE SHOWS CONVECTION NEAR INDIANAPOLIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING WITH A BRIEF BREAK BEFORE ADDITIONAL CONVECTION ARRIVES IN THE LATE AFTERNOON. TRIED TO INCORPORATE THIS INTO THE LATEST POP FORECAST BUT MAINTAINED FAIRLY BROADBRUSH APPROACH GIVEN UNCERTAINTY IN CONVECTIVE TRENDS. HIGHER CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD BY TONIGHT THOUGH AS THE COLD FRONT APPROACHES...AND HAVE PUSHED POPS INTO CATEGORICAL VALUES. HIGHS TODAY WILL BE SIMILAR TO YESTERDAY...AS ANY BREAKS IN THE CLOUD COVER WILL ALLOW TEMPS TO MAKE A RUN AT THE MID 80S GIVEN WARM PROFILES ALOFT. LOWS TONIGHT WILL BE HIGHLY DEPENDENT ON EXACT TIMING OF FRONT BUT HAVE RAISED THEM A BIT IN ANTICIPATION OF A SLOWER FRONTAL PASSAGE. LAPSE RATES NEARLY MOIST ADIABATIC WILL LIKELY ONLY SUPPORT AROUND 1000 J/KG OR LESS OF SBCAPE TODAY. DEEP LAYER SHEAR IS ALSO MARGINAL DURING THE DAY AND EXPECT ONLY A SLIGHT CHANCE FOR SEVERE WEATHER...MAINLY IN AREAS THAT SEE A SUSTAINED PERIOD OF INSOLATION THAT ALLOWS INSTABILITY TO BUILD. SHEAR WILL INCREASE BY TONIGHT...BUT INSTABILITY WILL BE AT A MINIMUM AND AGAIN ONLY EXPECTING A LOW RISK OF SEVERE WEATHER AT THE MOMENT. HEAVY RAIN WILL LIKELY BE THE BIGGEST THREAT. A VERY MOIST ENVIRONMENT AND CONTINUED POTENTIAL FOR TRAINING STORMS COULD LEAD TO HIGH RAINFALL TOTALS BY THE TIME ALL IS SAID AND DONE EARLY NEXT WEEK. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM EDT SAT OCT 5 2013 RATHER DRAMATIC CHGS REQUIRED TO BEGIN THE PD ON ACCOUNT OF CONTD MODEL CONSENSUS SLWG IN EWD PROGRESSION OF PLAINS BOWLING BALL. INTERESTINGLY STILL SOME SIG SPREAD ALOFT STILL AT THIS TIME RANGE W/POSITION AND INTENSITY OF MID LVL CYCLONE WHICH RANGES FROM NRN IL IN NAM TO SRN IL IN GEM AT FHR60. REGARDLESS ENOUGH OF A CONSENSUS SIGNAL EXISTS TO EXTEND/BUMP POPS/WX THROUGH MON NIGHT. HWVR WILL FORGO ALLBLEND POP GUIDANCE FOR TUE IN LIGHT OF RAPID UPSTREAM HGT RISES FOLLOWING IN WAKE OF UPR TROUGH WHICH AT THAT POINT SHLD BE IN SE CANADA. OF GREATEST INTEREST W/SLWG SOLUTIONS ALOFT IS CONTD PUMP OF ANOMALOUS GOMEX MSTR FLUX INTO THE GREAT LAKES INADV OF MIDLVL CYCLONE WHICH SHOWS LTL SIGN OF WKNG UNTIL MON. SLWR EWD ADV OF FNTL BNDRY ALG W/PWS OF NEAR 1.8IN (99TH PERCENTILE) WOULD PREPOSE AT LEAST THE ERN HALF OF CWA FOR A CLASSIC MADDOX TYPE I HEAVY RAIN EVENT AND NOTED IN SVRL DETERMINISTIC QPF SOLUTIONS SUN-SUN NIGHT. SINCE THIS THREAT IS XPCD TO DVLP DY2 WILL FOLLOWUP PRIOR WELL DESERVED ESF. AS AN ASIDE...FAIR NUMBER OF SOLUTIONS DEPICT THE DVLPMNT OF A SFC FNTL WAVE SUN AFTN WHICH IF TRUE WOULD YIELD A HEIGHTENED RISK FOR LOW TOPPED SUPERCELLS ACRS ERN IN/WRN OH AND INHERENT TOR THREAT W/FVRBL OVERLAP OF MIXED LYR CAPE/SHEAR. OTRWS SWD TRENDING PROGRESSION OF AT LEAST MOD INTENSE MID LVL CYCLONE LEADS TO ADDNL ESCALATION/EXPANSION OF POPS MON AFTN/MON NIGHT. IN FACT SWD CNTRD CLUSTER OF SVRL SOLUTIONS INCLUDING GFS/GEM WOULD PORTEND A SECONDARY DEFORMATION ZONE DVLPG IN RESPONSE TO TRAILING FNTL WAVE MON NIGHT W/ASSUMED SEPARATION W/REMNANTS OF TS KAREN AS SOME SEMBLANCE OF THE TROWAL REMAINS INTACT. GIVEN ALL OF THE ABOVE...SIG CHGS TO TEMPS WERE MADE SUN/MON. HWVR SIG MODERATION STILL ON TAP IN WAKE OF THIS INTENSE SYS MID WEEK TIMED W/SECONDARY DEEP WRN TROUGH DVLPMNT AND DOWNSTREAM RIDGE AMPLIFICATION W/RTN TO ABV NORMAL TEMPS XPCD BY THU. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 145 PM EDT SAT OCT 5 2013 CONVECTION BEGINNING TO INCREASE IN COVERAGE FROM SOUTHERN ILLINOIS INTO SOUTHWEST LOWER MICHIGAN WITH A POCKET OF 1000-2000 J/KG OF 100 HPA MLCAPES ACROSS THE REGION. A COUPLE OF SHORT WAVES EMBEDDED IN SOUTHWEST UPPER FLOW WILL AID IN EXPANSION OF SHRA/TSRA COVERAGE THROUGH EARLY EVENING ACROSS NORTH CENTRAL INDIANA...WITH LIKELIHOOD OF SHOWERS AND EMBEDDED THUNDERSTORMS OVERSPREADING NORTHEAST INDIANA THROUGH THE EARLY TO LATE EVENING HOURS. DIURNAL MIXING HAS IMPROVED THE IFR CIGS TO MVFR AT KSBN EARLY THIS AFTERNOON. HAVE MAINTAINED TEMPO MVFR CONDS IN HEAVIER SHOWERS AND THUNDERSTORMS THIS AFTERNOON/EARLY EVENING...WITH TREND BACK TO IFR CONDITIONS LATE EVENING/HOUR NIGHT AS DEEPER MOISTURE LIFTS NORTHWARD INTO THE AREA. A BRIEF LULL IN COVERAGE OF SHOWERS AND THUNDERSTORMS IS POSSIBLE IN THE 04Z-08Z TIMEFRAME...BUT SHOULD INCREASE ONCE AGAIN TOWARD DAYBREAK AS LARGE SCALE FORCING/LOW LEVEL FRONTOGENESIS INCREASES WITH APPROACHING UPPER TROUGH && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR INZ007-009-018-026-027-033-034. MI...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR MIZ081. OH...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR OHZ001-002-004-005-015-016-024-025. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1147 AM EDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 342 AM EDT SAT OCT 5 2013 A LARGE LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK. THIS LOW PRESSURE SYSTEM WILL ALSO SEND A COLD FRONT THROUGH THE AREA WITH TEMPERATURES RETURNING TO NEAR NORMAL VALUES AFTER HIGHS IN THE LOW 80S AGAIN TODAY. && .UPDATE... ISSUED AT 1125 AM EDT SAT OCT 5 2013 A COUPLE OF SMALL SCALE EMBEDDED WAVES IN SOUTHWEST UPPER FLOW HAVE RESULTED IN CLUSTERS OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL/NORTHEAST INDIANA. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OTHER SOUTHERN LAKE MICHIGAN IN CLOSER PROXIMITY TO MORE PRONOUNCED UPPER LEVEL DIFFLUENCE DOWNSTREAM OF VIGOROUS NORTHERN PLAINS UPPER TROUGH. AREAS ROUGHLY ALONG AND SOUTHEAST OF A HUNTINGTON INDIANA TO FORT WAYNE INDIANA TO DEFIANCE LINE HAVE LIKELY RECEIVED BETWEEN A HALF INCH TO AN INCH OF RAINFALL SO FAR THIS MORNING. SOME OF THESE SAME LOCATIONS ACROSS NORTHWEST OHIO HAVE ALSO RECEIVED HEAVY RAINFALL YESTERDAY. GIVEN INCREASING CONFIDENCE IN SIGNIFICANT RAINFALL LATE TONIGHT INTO SUNDAY EVENING ALONG WITH RECENT HEAVY RAIN...WILL BE ISSUING A FLASH FLOOD WATCH SHORTLY FOR FAR NORTHEAST INDIANA...PORTIONS OF SOUTH CENTRAL LOWER MICHIGAN....AND ALL OF NORTHWEST OHIO COUNTIES FROM 06Z TONIGHT TO 06Z MONDAY. IN TERMS OF CONVECTIVE POTENTIAL...15Z RUC ANALYSIS DEPICTS 1000-1500 J/KG OF 100 HPA MLCAPES ACROSS MUCH OF WESTERN HALF OF THE AREA WITH 0 TO 6 KM BULK SHEAR VALUES IN THE 25 TO 30 KNOT RANGE. DESPITE SIGNIFICANT CLOUD COVER...DEEP MOISTURE PROFILES SHOULD CONTINUE TO YIELD CAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. DEEP LAYER SHEAR TO ALSO INCREASE LATE AFTERNOON ACROSS WESTERN HALF OF THE AREA AS A 500 HPA SPEED MAX LIFTS INTO NORTHWEST INDIANA AFTER 21Z. THUS...NO CHANGE IN THINKING FROM PREVIOUS FORECAST WITH LOW/ISOLATED SEVERE THREAT ACROSS ESPECIALLY WESTERN AREAS LATE AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM EDT SAT OCT 5 2013 GRADUAL APPROACH OF IMPRESSIVE CLOSED OFF CYCLONIC GYRE EXTENDING THROUGH THE BULK OF THE TROPOSPHERE WILL BRING INCREASING CHANCES FOR RAIN THROUGH THE SHORT TERM PERIOD. SURFACE FRONTAL BOUNDARY EXTENDING INTO THE SOUTHERN GREAT LAKES WILL MOVE LITTLE THROUGH THE PERIOD WITH PERSISTENT THETA-E ADVECTION IN A LARGELY UNCAPPED ENVIRONMENT LEADING TO CONTINUED PERIODS OF CONVECTION. SMALL SCALE VORTICES IN SOUTHWEST FLOW ALOFT EMANATING FROM THE CENTRAL CONUS WILL ALSO SUPPORT INCREASING CHANCES FOR RAINFALL AS THE MAIN SYSTEM APPROACHES. OCCLUSION PROCESS IS ALREADY BEGINNING AND EARLIER NOTED SLOWING TREND HAS CONTINUED. MAIN SURFACE COLD FRONT IS NOT EXPECTED TO REACH OUR CWA UNTIL LATE TONIGHT. WILL STILL BE PLENTY OF RAIN AHEAD OF THE MAIN FRONT THOUGH. TIGHTENING LOW LEVEL MASS GRADIENT ASSOCIATED WITH APPROACHING PV ANOMALY WILL LEAD TO A STRENGTHENING OF THE LLJ AND A CORRESPONDING UPTICK IN 305K ISENTROPIC ASCENT. MOISTURE WILL CERTAINLY NOT BE LACKING EITHER. 305K MIXING RATIOS ARE ABOVE 8 G/KG AND PW VALUES ARE HOVERING AROUND 1.75 INCHES...NEAR THE 99TH PERCENTILE FOR THIS TIME OF YEAR BASED ON REGIONAL UPPER AIR CLIMATOLOGY. EXACT TIMING/PLACEMENT OF CONVECTION REMAINS HIGHLY UNCERTAIN BUT EXPECT COVERAGE TO INCREASE AS THE DAY WEARS ON GIVEN INCREASING DIURNAL INSTABILITY AND APPROACHING TROUGH. LATEST HI-RES GUIDANCE SHOWS CONVECTION NEAR INDIANAPOLIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING WITH A BRIEF BREAK BEFORE ADDITIONAL CONVECTION ARRIVES IN THE LATE AFTERNOON. TRIED TO INCORPORATE THIS INTO THE LATEST POP FORECAST BUT MAINTAINED FAIRLY BROADBRUSH APPROACH GIVEN UNCERTAINTY IN CONVECTIVE TRENDS. HIGHER CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD BY TONIGHT THOUGH AS THE COLD FRONT APPROACHES...AND HAVE PUSHED POPS INTO CATEGORICAL VALUES. HIGHS TODAY WILL BE SIMILAR TO YESTERDAY...AS ANY BREAKS IN THE CLOUD COVER WILL ALLOW TEMPS TO MAKE A RUN AT THE MID 80S GIVEN WARM PROFILES ALOFT. LOWS TONIGHT WILL BE HIGHLY DEPENDENT ON EXACT TIMING OF FRONT BUT HAVE RAISED THEM A BIT IN ANTICIPATION OF A SLOWER FRONTAL PASSAGE. LAPSE RATES NEARLY MOIST ADIABATIC WILL LIKELY ONLY SUPPORT AROUND 1000 J/KG OR LESS OF SBCAPE TODAY. DEEP LAYER SHEAR IS ALSO MARGINAL DURING THE DAY AND EXPECT ONLY A SLIGHT CHANCE FOR SEVERE WEATHER...MAINLY IN AREAS THAT SEE A SUSTAINED PERIOD OF INSOLATION THAT ALLOWS INSTABILITY TO BUILD. SHEAR WILL INCREASE BY TONIGHT...BUT INSTABILITY WILL BE AT A MINIMUM AND AGAIN ONLY EXPECTING A LOW RISK OF SEVERE WEATHER AT THE MOMENT. HEAVY RAIN WILL LIKELY BE THE BIGGEST THREAT. A VERY MOIST ENVIRONMENT AND CONTINUED POTENTIAL FOR TRAINING STORMS COULD LEAD TO HIGH RAINFALL TOTALS BY THE TIME ALL IS SAID AND DONE EARLY NEXT WEEK. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM EDT SAT OCT 5 2013 RATHER DRAMATIC CHGS REQUIRED TO BEGIN THE PD ON ACCOUNT OF CONTD MODEL CONSENSUS SLWG IN EWD PROGRESSION OF PLAINS BOWLING BALL. INTERESTINGLY STILL SOME SIG SPREAD ALOFT STILL AT THIS TIME RANGE W/POSITION AND INTENSITY OF MID LVL CYCLONE WHICH RANGES FROM NRN IL IN NAM TO SRN IL IN GEM AT FHR60. REGARDLESS ENOUGH OF A CONSENSUS SIGNAL EXISTS TO EXTEND/BUMP POPS/WX THROUGH MON NIGHT. HWVR WILL FORGO ALLBLEND POP GUIDANCE FOR TUE IN LIGHT OF RAPID UPSTREAM HGT RISES FOLLOWING IN WAKE OF UPR TROUGH WHICH AT THAT POINT SHLD BE IN SE CANADA. OF GREATEST INTEREST W/SLWG SOLUTIONS ALOFT IS CONTD PUMP OF ANOMALOUS GOMEX MSTR FLUX INTO THE GREAT LAKES INADV OF MIDLVL CYCLONE WHICH SHOWS LTL SIGN OF WKNG UNTIL MON. SLWR EWD ADV OF FNTL BNDRY ALG W/PWS OF NEAR 1.8IN (99TH PERCENTILE) WOULD PREPOSE AT LEAST THE ERN HALF OF CWA FOR A CLASSIC MADDOX TYPE I HEAVY RAIN EVENT AND NOTED IN SVRL DETERMINISTIC QPF SOLUTIONS SUN-SUN NIGHT. SINCE THIS THREAT IS XPCD TO DVLP DY2 WILL FOLLOWUP PRIOR WELL DESERVED ESF. AS AN ASIDE...FAIR NUMBER OF SOLUTIONS DEPICT THE DVLPMNT OF A SFC FNTL WAVE SUN AFTN WHICH IF TRUE WOULD YIELD A HEIGHTENED RISK FOR LOW TOPPED SUPERCELLS ACRS ERN IN/WRN OH AND INHERENT TOR THREAT W/FVRBL OVERLAP OF MIXED LYR CAPE/SHEAR. OTRWS SWD TRENDING PROGRESSION OF AT LEAST MOD INTENSE MID LVL CYCLONE LEADS TO ADDNL ESCALATION/EXPANSION OF POPS MON AFTN/MON NIGHT. IN FACT SWD CNTRD CLUSTER OF SVRL SOLUTIONS INCLUDING GFS/GEM WOULD PORTEND A SECONDARY DEFORMATION ZONE DVLPG IN RESPONSE TO TRAILING FNTL WAVE MON NIGHT W/ASSUMED SEPARATION W/REMNANTS OF TS KAREN AS SOME SEMBLANCE OF THE TROWAL REMAINS INTACT. GIVEN ALL OF THE ABOVE...SIG CHGS TO TEMPS WERE MADE SUN/MON. HWVR SIG MODERATION STILL ON TAP IN WAKE OF THIS INTENSE SYS MID WEEK TIMED W/SECONDARY DEEP WRN TROUGH DVLPMNT AND DOWNSTREAM RIDGE AMPLIFICATION W/RTN TO ABV NORMAL TEMPS XPCD BY THU. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 555 AM EDT SAT OCT 5 2013 AREA OF CONVECTION CURRENTLY OVER CENTRAL INDIANA WILL CONTINUE TO SLOWLY WORK NORTHWARD THIS MORNING...AIDED BY PERSISTENT THETA-E ADVECTION AND A WEAK SHORTWAVE EMBEDDED IN SOUTHWEST FLOW ALOFT. PRECIP MAY CLIP KFWA BUT PLAN TO LEAVE OUT THUNDER MENTION SINCE LIGHTNING HAS BEEN FAIRLY ISOLATED AND MAY PASS TO THE SOUTHEAST OF THE TERMINAL. SPORADIC SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE FOR MUCH OF THE TAF PERIOD AND TIMING THIS PRECIP WILL BE NEARLY IMPOSSIBLE MORE THAN A FEW HOURS OUT. HAVE HIGHLIGHTED LATE AFTERNOON AS THE BEST CHANCE GIVEN DIURNAL INSTABILITY PEAK BUT SCATTERED CONVECTION WILL BE POSSIBLE THROUGH THE OVERNIGHT PERIOD WITH MVFR...OR LOWER...CONDITIONS IN THE STRONGER STORMS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR INZ007-009-018-026-027-033-034. MI...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR MIZ081. OH...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR OHZ001-002-004-005-015-016-024-025. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
323 PM CDT Sat Oct 5 2013 .SHORT TERM...(This Evening through Sunday) Issued at 320 PM CDT SAT OCT 5 2013 20Z water vapor imagery shows the closed upper low over southeast SD slowly propagating east. A shortwave trough axis has rotated through eastern KS helping to clear out the mid level clouds. At the surface the cold front had pushed well east and south with dry cool air advecting in from the west. For tonight and Sunday, the forecast calls for generally dry weather as there is little moisture to work with and large scale forcing should remain to the north and east of the forecast area. Did leave some slight chance pops in the far northeastern corner of the forecast area during the day Sunday. As the upper low drifts across southwest IA, lapse rates could steepen enough for some isolated showers to move across Nemaha and Brown counties. The main thing to watch will be the STRATOCU deck to the north. The RAP and NAM show these clouds eventually moving into much of the forecast area overnight. This should have an impact on MIN and MAX temps. Models are in good agreement that the boundary layer will remain well mixed overnight with increasing clouds from the north. Therefore am fairly confident that MIN temps will not fall below 40 and even tweaks temps up a degree or two. The forecast may still be on the cool side if the clouds move in quicker. Highs Sunday are expected to warm back into the 60s for most areas. Forecast soundings mix the boundary layer almost to 800MB and models indicate the cold air advection will have ended. The main question is whether clouds will hold temps down. Added about 3 to 5 degrees to MAX temps across the western and southern counties where there should be more insolation with good mixing. Across northeastern KS where clouds are likely to hang in tough, kept highs in the middle 50s. Wolters .LONG TERM...(Sunday Night through Saturday) Issued at 320 PM CDT SAT OCT 5 2013 Upper low still on track to progress eastward through the mid MO and OH river valleys through Monday. Most of the moisture wrapping around the backside of the exiting upper may linger across the far northeast corner of the cwa early Sunday evening...so have left a slight chance in for that time period. Otherwise will go with a dry fcst Monday through Thursday night as upper level ridging will develop across the plains in the wake of the first trough exiting trough and ahead of the second upper trough that deepens over the west CONUS. Will continue to slowly but steadily increase high temps through the 70s Monday through Thursday...with a few low 80s on Thursday. As the western trough then lift out into the plains on Friday and Friday night...with more clouds and the potential for showers and thunderstorms cooled temps slightly for Friday before the frontal passage and and even cooler readings in the low to middle 70s on Saturday. Warmed low temps from near 40 Monday morning into the 50s by Wednesday on through the end of the week. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1209 PM CDT SAT OCT 5 2013 VFR forecast at KTOP/KFOE/KMHK with west winds gusting between 15 and 23 kts this afternoon. Winds stay up near 10 kts overnight as upper low passes to the northeast. Latest RAP and high res guidance are hinting at cigs redeveloping aft 08z at KMHK and 09z at KTOP/KFOE. Not confident enough to lower to MVFR however increased VFR cloud coverage at this time and will reevaluate MVFR potential at next issuance. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...63 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1233 PM CDT Sat Oct 5 2013 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 316 AM CDT SAT OCT 5 2013 Closed upper level low is currently centered over central SD with a well defined mid level dry punch stretched across the central plains. Surface cold front responsible for yesterday`s thunderstorms has moved east into western MO. Trailing stratiform behind the main line of thunderstorms will continue for a few more hours in the far southeast cwa. An area of scattered showers with isolated thunder is working through parts of the cwa this morning due to some elevated instability rooted at around 750 mb. These showers will move northeast through the cwa during the next few hours exiting the area by sunrise. Cold dry air has begun to push into the region behind the front with temperatures in the mid 40s already in north central KS. Low temperatures tonight will range from the low 40s in north central KS to the upper 50s in east central KS. The winds have shifted to the west northwest and are forecast to increase to around 15 to 20 mph with gusts up to 30 mph during the day today. Clouds will continue to move east today with partly to mostly sunny skies expected by this afternoon and high temperatures in the upper 50s to low 60s. Cold air advection will persist through out the day today and tonight. The 850 mb temperatures will approach 0C later tonight therefore overnight low temperatures drop to around 40 across most of the area. .LONG TERM...(Sunday through Friday) Issued at 316 AM CDT SAT OCT 5 2013 Through Sunday afternoon the upper low is forecast to drop east southeast out from near Sioux Falls into Missouri. This takes an area of stratus and the colder air aloft across the northeastern counties. By afternoon hours, there is enough lift associated with the low to generate showers through the saturated layer in the column. In fact 850mb temperatures are running just near or below freezing, and soundings suggest the top of the lift in the column just clips where the -10/-20 layer is saturated aloft. However expect to see enough warmer air in the low levels to keep precip in the form of rain or a light drizzle. Could go on for a few hours in the afternoon, and would not be surprised to see some cold air funnels ad cold pool moves through. This will also keep high temperatures across the NE down int he 50s with 60s possible elsewhere. Mon-Fro continue to advertise a nice warm up through the end of the week as Monday starts out around 70 and Friday brings highs in the upper 70s. Lows Sunday night into Morning may be pretty chilly as skies clear and winds lighten before warm air advection returns. May see lows around 40 common over the area. These lows slowly moderate back into the 50s as southwesterly flow aloft returns to the plains and the next trof approaches the Rockies on Friday. Will carry just a slight chance for some pops mainly in the western counties. 67 && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1209 PM CDT SAT OCT 5 2013 VFR forecast at KTOP/KFOE/KMHK with west winds gusting between 15 and 23 kts this afternoon. Winds stay up near 10 kts overnight as upper low passes to the northeast. Latest RAP and high res guidance are hinting at cigs redeveloping aft 08z at KMHK and 09z at KTOP/KFOE. Not confident enough to lower to MVFR however increased VFR cloud coverage at this time and will reevaluate MVFR potential at next issuance. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sanders LONG TERM...67 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS JACKSON KY
553 PM EDT SAT OCT 5 2013 .UPDATE... ISSUED AT 553 PM EDT SAT OCT 5 2013 SHOWERS/THUNDERSTORMS WHICH DEVELOPED IN CENTRAL KY HAVE HELD TOGETHER AS THEY MOVED INTO THE JKL FORECAST AREA...BUT WERE WEAKENING. UPDATED TO INCREASE POPS FOR EARLY THIS EVENING IN OUR NORTHERN COUNTIES. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 303 PM EDT SAT OCT 5 2013 COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z TUESDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIR MASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
303 PM EDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 303 PM EDT SAT OCT 5 2013 COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z TUESDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIRMASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
301 PM EDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 301 PM EDT SAT OCT 5 2013 ALL MODELS ARE STILL ON TRACK TO BRING US A POTENT AND SLOW MOVING COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z MONDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIRMASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
927 PM EDT SUN OCT 6 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ALONG THE EASTERN SEABOARD THIS EVENING. A STRONG COLD FRONT WILL APPROACH THE REGION OVERNIGHT... AND CROSS THE REGION MONDAY. HIGH PRESSURE BUILDS IN FROM THE WEST TUESDAY THROUGH THURSDAY. && .NEAR TERM /THROUGH MONDAY/... A COLD FRONT EXTENDS FROM THE UPPER GREAT LAKES SOUTH THROUGH THE OHIO VALLEY AND INTO THE GULF COAST STATES REACHING THE REMENENTS OF WHAT WAS TS KAREN THIS EVENING. HIGH PRESSURE HAS MOVED OFF THE COAST AND THE MID ATLANTIC IS RECEIVING RETURN FLOW AS SOUTHERLY WINDS HAVE INCREASED. THE PRESSURE GRADIENT HAS TIGHTENED AND MOISTURE WILL CONTINUE TO MOVE INTO THE REGION AHEAD OF THE ADVANCING COLD FRONT. ALTHOUGH AIR MASS IS STILL QUITE DRY AS 00Z IAD RAOB SHOWS DRY AIR ALOFT LOW STRATUS CLOUDS WILL FORM ACROSS THE REGION TONIGHT. THESE CLOUDS ARE STARTING TO SHOW UP ALONG THE MTN RIDGES ON THE 11-3.9 SAT CHANNEL. PER 00Z IAD RAOB...SOUTHERLY FLOW HAS INCREASED TO 25-30 KTS AT 850MB AND WILL INCREASE TO 40 KTS BY 12Z MONDAY. ISENTROPIC LIFT AND MOISTURE ADVECTION WILL SPREAD LOW CLOUDS NORTHWARD MAKING IT TO I-95 BY SUNRISE MONDAY MORNING. AS LLJ INCREASES SHOWERS WILL MOVE INTO THE REGION AS WELL. 3KM HRRR HAS ISO-SCT SHOWERS FORMING AND MOVING NORTHWARD OVERNIGHT AND INTO MONDAY MORNING. COLD FRONT WILL BE AT THE ALLEGHENY FRONT MONDAY MORNING AND SHOWERS AND GUSTY WINDS WILL BEGIN TO PROPAGATE EASTWARD TOWARD THE CHESAKPEAKE BAY. && .SHORT TERM /MONDAY NIGHT/... CONDITIONS WILL DETERIORATE ON MONDAY WITH THE APPROACH OF THE COLD FRONT FROM THE WEST. THE MAIN AREA OF SHOWERS SHOULD CROSS I-81 AND REACH THE BLUE RIDGE BEFORE NOON...THEN SPREAD EAST ACROSS THE REMAINDER OF THE REGION BY OR JUST AFTER NOON. WL BE IN A HIGH SHEAR/LOW CAPE ENVIRONMENT...BUT DEWPTS IN THE MID 60S AND A LOW LVL JET UPWRDS OF 50 KT MAY BE ABLE TO INDUCE SOME CNVCTV DVLPMNT-- LKLY LOW-TOPPED BUT STILL CAPABLE OF PRODUCING DOWNDRAFTS AND A FEW SPINNERS. SPC HAS ADDED A SLGT RISK AREA TO DAY 2 OUTLK...INCL NE MD. W/ PWAT NEAR 2 INCHES...WL BE PLACING EMPHASIS IN WX GRIDS ON THE SHRA...AS SOME CNVCTN MAY BE LACKING THUNDER/LTNG. A PLUME OF MSTR WL BE TRANSPORTED NWD AHD OF CDFNT...W/ PLENTY OF LIFT ALONG FRNTL BNDRY. HV RAISED POPS TO 100 PCT. ORDINARILY...THESE ANTICIPATED RAFL RATES IN OCT WUD LEAD TO AUTOMATIC FLASH FLOODING CONCERNS. HWVR...AREA HAS BEEN SO DRY RECENTLY THAT WL STILL BE HOLDING OFF ON ANY WATCH ISSUANCE. CANNOT RULE OUT LCLZD ISSUES DUE TO HARD GRND IF HVY RAFL IS PROLONGED. THAT CUD BE A CONSIDERATION FOR FCSTRS TNGT/TMRW MRNG. CDFNT WL BE CROSSING DELMARVA BY ELY-MID EVNG. CLRG SKIES...A DRYING AMS...AND NW/NLY WNDS WL ENSUE FOR THE BALANCE OF THE NGT. MOS GDNC FOR MAXT DROPPED QUITE A BIT FM PRVS CYCLES. WHILE AGREE THAT CLDS/RAFL WL IMPEDE DIURNAL TEMP RISE...AM LEERY OF TEMPS FALLING OFF TOO MUCH DUE TO STRONG SLY FLOW. SHADED MAXT DOWN ONLY A CPL DEGF FM PRVS FCST. DID LOWER QUITE A BIT FOR MIN-T MON NGT THO && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGH PRESSURE BUILDS INTO NEW ENGLAND FROM THE OHIO VALLEY ON TUESDAY...PUTTING OUR REGION IN NE FLOW WITH MOSTLY CLEAR SKIES. 06/00Z MEX GDNC IS GIVING THE AREA NEAR NORMAL TEMPS WITH HIGHS AROUND 70 AND NIGHTIME LOWS IN THE MID 40S. ON THURSDAY...BOTH THE 06/00Z GFS AND 05/12Z ECMWF CUT AN UPPER LOW OFF THE NC COAST WITH THE SFC REFLECTION A LARGE WARM CORE LOW PRESSURE SYSTEM. THE AREA OFF THE NC/SC IN OCTOBER IS A FAVORED REGION FOR LIKELY TROPICAL DEVELOPMENT PER NHC CLIMO DATA. THE EXTENDED GFS MEANDERS THE LOW OFF THE COAST BEFORE FINALLY TAKING IT OUT TO SEA. RIGHT NOW RUNNING WITH WPC GUIDANCE FOR DAYS 4-7...WHICH CONTINUES THE REGION IN NE FLOW AND FAIR WEATHER THROUGH SATURDAY. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS EXPECTED TONIGHT. MVFR/IFR CIGS EXPECTED EARLY MONDAY MORNING. A STRONG SOUTHERLY JET WILL ADVECT MOISTURE INTO THE REGION. ISO-SCT SHOWERS ARE POSSIBLE ACROSS THE TERMINALS OVERNIGHT WHILE HEAVY RAIN APPROACHES MRB BY LATE MONDAY MORNING. GUSTY WINDS...HEAVY RAIN AND LIGHTNING ARE ALL POSSBILE AHEAD AND ALONG COLD FRONT. A 40 KT JET AT 240 DEG AT 2K FEET MAY PRODUCE LLWS MONDAY MORNING BUT CONFIDENCE IS LOW AT THIS TIME. VSBYS WILL BE REDUCED IN HEAVY SHOWERS AND ISO THUNDERSTORMS. BEST TIMING WILL BE MONDAY AFTERNOON FOR TS. COLD FRONT WILL CROSS BWI- MTN BY LATE MON AFTERNOON. NW FLOW BEHIND FRONT WILL CONTINUE THROUGH TUESDAY MORNING. VFR CONDITIONS EXPECTED AFTER COLD FRONT. FOR THE EXTENDED AVIATION BEYOND MONDAY NIGHT...LOOKING FOR VFR CONDITIONS AT ALL TERMINALS TUESDAY THROUGH THURSDAY WITH NE WINDS LIKELY AS HIGH IS CENTERED OVER NEW ENGLAND. && .MARINE... S-SE FLOW WILL CONTINUE ACROSS THE POTOMAC AND BAY TONIGHT AND MONDAY. A COLD FRONT WILL CROSS THE WATERS MONDAY AFTERNOON AND HEAVY RAIN AND GUSTY WINDS ARE EXPECTED. SOUTHERLY WINDS MAY GUST NEAR GALE CRITERIA TOWARDS LATE MONDAY MORNING AS STRONG JET ALOFT MIXES DOWN. THESE WILL SUBSIDE SOME TOWARDS THE AFTERNOON. WATERSPOUTS AND LIGHTNING ARE ALSO POSSIBLE AHEAD OF COLD FRONT MON AFTERNOON. A SCA IS IN EFFECT THROUGH THE FRONTAL PASSAGE MONDAY NIGHT FOR MOST WATER ZONES. AFTER THE FRONTAL PASSAGE...NW WINDS WILL INCREASE AND A SCA IS IN EFFECT MONDAY NIGHT INTO EARLY TUESDAY MORNING FOR THE BAY SOUTH OF NORTH BEACH AND LOWER TIDAL POTOMAC. NO MORE MARINE HEADLINES EXPECTED THROUGH THE REMAINDER OF THE MARINE PERIOD/THURSDAY/. && .TIDES/COASTAL FLOODING... SOUTHERLY FLOW HAS INCREASED AND WILL CONTINUE TO INCREASE AHEAD OF AN APPROACHING COLD FRONT IN THE OHIO VALLEY. TIDAL ANOMALIES HAVE INCREASED TO AROUND A FOOT ACROSS THE WESTERN SHORE OF THE MD CHESAPEAKE BAY AND TIDAL POTOMAC. A CF ADVISORY IS IN EFFECT FOR THE NEXT HIGH TIDE CYCLES ON THE WESTERN SHORE OF THE BAY. THE HIGH TIDE FOR DC/SW WATERFRONT IS CURRENTLY REACHING MINOR THRESHOLD TONIGHT. LOCATIONS THAT HAVE HIGH TIDES PRIOR TO COLD FRONT PASSAGE WILL BE SUSEPTIBLE TO MINOR INUNDATION. XPCT TIDAL DEPARTURES TO INCREASE FURTHER ON MON...BUT ITS THE LOWER OF THE TWO TIDES ASTRONOMICALLY. THAT MAY BALANCE EACH OTHER OUT. THE EXTENT OF THE SLY FLOW MAY SUGGEST THAT THE MON DAYTIME TIDE MAY BE THE HIGHEST. GDNC SUGGESTING THAT TOO. WINDS BECOME NWLY MON EVNG...BUT MAY NOT BE ENOUGH FOR A RAPID BLOWOUT. TIMING WL BE KEY IN DETERMINING IF THERE WILL BE ISSUES FOR THE MON NIGHT TIDE CYCLE. && .CLIMATE... RECORD HIGH TEMP OF 89 DEGREES WAS SET AT IAD TODAY BREAKING THE OLD RECORD OF 86 DEGREES IN 1995. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR DCZ001. MD...COASTAL FLOOD ADVISORY FROM 2 AM TO 11 AM EDT MONDAY FOR MDZ011-014-017-018. COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MDZ011- 014. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT MONDAY FOR ANZ530- 535-536-538-539. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ531>534-537- 540>543. SMALL CRAFT ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR ANZ532>534-537-540>543. && $$ SYNOPSIS...HTS NEAR TERM...HAS SHORT TERM...LEE/HAS/HTS LONG TERM...LEE AVIATION...LEE/HAS MARINE...LEE/HAS TIDES/COASTAL FLOODING...HAS CLIMATE...HAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
756 PM EDT SUN OCT 6 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE WRN CONUS AND A TROUGH FROM HUDSON BAY INTO NRN ONTARIO. THE PERSISTENT MID/UPPER LEVEL LOW HAD EDGED EASTWARD INTO ERN IA. AT THE SFC...LOW PRES WAS LOCATED OVER S CNTRL LAKE SUPERIOR WITH A COLD FRONT INTO CNTRL LOWER MI AND A TROUGH TO THE SW INTO SE MN. RAIN ASSOCIATED WITH A WEAK SHORTWAVE IN THE WARM CONVEYOR AHEAD OF THE COLD FRONT WAS LIFTING NNE THROUGH ERN CWA. OTHERWISE...RADAR INDICATED ONLY VERY WEAK RETURNS OVER THE WEST WITH SOME SPRINKLES OR DRIZZLE. FARTHER WEST...A NARROW BAND OF RAIN TO NEAR DLH WAS ASSOCIATED WITH THE MID LEVEL DEFORMATION/FGEN BAND/TROWAL ON THE NRN FLANK OF THE MID LEVEL LOW. VIS LOOP SHOWED CLEARING OVER SRN UPPER MI WITH THE ADVANCING DRY SLOT. TONIGHT...MODELS SUGGEST THAT THE NE MN RAIN BAND WILL CONTINUE TO SLOWLY SPREAD INTO WEST UPPER MI THIS EVENING AND GRADUALLY SHRINK OVERNIGHT...PER FCST 310KE SURFACE. THERE MAY ALSO BE A FEW LIGHT SHOWERS THROUGH CNTRL UPPER MI THIS EVENING AS THE DRY SLOT AREA GIVES WAY TO INCREASING CLOUDS WITH INCREASING 700-300 MB QVECTOR CONV AND LOW LEVEL CONV NEAR THE TROUGH. IN ADDITION...SOME LAKE ENHANCED SHOWERS MAY DEVELOP OVERNIGHT AS 850 MB TEMPS DROP TO AROUND 1C WITH NNW LOW CYCLONIC FLOW INCREASING. SO...CHANCE POPS WERE MAINTAINED OVER MOST OF THE CWA TONIGHT EVEN IF ONLY INTERMITTENT PERIODS OF RAIN DEVELOP. MONDAY...THE REMAINING SYNOPTIC AND LAKE ENHANCED PCPN OVER THE EAST IS EXPECTED TO DIMINISH DURING THE MORNING AS THE MID LEVEL QVECTOR CONV FORCING AND DEEPER MOISTURE DEPART TO THE EAST. OTHERWISE...GRADUAL CLEARING AND SOME SUNSHINE DURING THE AFTERNOON WILL BRING TEMPS AGAIN TO NEAR SEASONAL NORMALS IN THE UPPER 50S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 QUIETER WEATHER WILL REPLACE THE UNSETTLED ACTIVITY OF THIS PAST WEEK STARTING MONDAY NIGHT. A 500MB RIDGE BUILDS ACROSS THE NORTHERN PLAINS BY 00Z TUESDAY...AND CONTINUES EASTWARD THROUGHOUT THE FORECAST PERIOD. SURFACE HIGH PRESSURE EXPANDS INTO THE GREAT LAKES DURING THE DAY TUESDAY...AND GRADUALLY CENTERS ITSELF OVER THE LOWER LAKES THROUGH FRIDAY AFTERNOON. THE ECMWF/GFS HAVE 925 MB TEMPS UP TO 14-15C FOR WEDNESDAY-FRIDAY AFTERNOON OUT WEST...WHICH PUTS HIGHS ROUGHLY IN THE UPPER 60S/NEAR 70. FOR THE REST OF THE AREA...EXPECT LOW TO MID 60S. BUMPED UP WINDS FOR TUESDAY AND WEDNESDAY TO ACCOUNT FOR TIGHTENING PRESSURE GRADIENT ACROSS UPPER MICHIGAN ASSOCIATED WITH THE SURFACE LOW MOVING JUST NORTH OF LAKE SUPERIOR AND HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES. THOUGH SOUTHERLY WINDS MAY GUST UP TO 20 KTS AND TEMPS WILL BE CLOSE TO 70...AFTERNOON RH WILL BE IN THE 35-40 PERCENT RANGE SO DO NOT EXPECT ANY FIRE WX CONCERNS. FRIDAY NIGHT INTO SUNDAY...A NEGATIVELY TILTED 500MB TROUGH/POSSIBLE CUT OFF LOW WILL DIVE INTO THE PLAINS. THIS WILL PROVIDE THE NEXT CHANCES FOR PRECIPITATION ACROSS UPPER MICHIGAN. RECENT MODEL RUNS HAVE THE SFC LOW PRESSURE SYSTEM MOVING NORTHEAST INTO HUDSON BAY BY SUNDAY MORNING...BRINGING A COLD FRONT ACROSS UPPER MI. BOTH THE GFS/ECMWF HAVE THIS...THOUGH THERE ARE DIFFERENCES IN TIMING...WITH THE GFS BRINGING THE FRONT THROUGH FRIDAY NIGHT AND THE ECMWF BRINGING IT THROUGH SATURDAY AFTERNOON. EVEN MORE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF SHOW UP ON SUNDAY AS ANOTHER TROUGH APPROACHES FROM THE WEST. THE GFS BRINGS SATURDAYS FRONT OUT OF UPPER MICHIGAN BY 12Z SUNDAY...AND THE DRY SLOT MOVES IN OVERHEAD WHICH ENDS PRECIPITATION. BY 00Z MONDAY IT HAS A SHORTWAVE SLIDING INTO THE DAKOTAS AND PRECIPITATION MOVING INTO WESTERN LAKE SUPERIOR OUT AHEAD OF IT. THE ECMWF KEEPS A STRONGER RIDGE OVER THE LOWER LAKES AND NEW ENGLAND STATES FOR SATURDAY AND SUNDAY...SO THE PROGRESSION OF THE FRONT ON SATURDAY IS SLOWER THAN THE GFS...AND IT STALLS OUT OVER CENTRAL/EASTERN UPPER MICHIGAN FOR SUNDAY. OVERALL...GENERAL CHANCE-SLIGHT CHANCE POPS ARE IN THE FORECAST FOR THESE DAYS. IT SEEMS BOTH MODELS HAVE BEEN FAIRLY INCONSISTENT FROM RUN TO RUN ON THE WEEKEND SOLUTION...SO WILL NOT GET CUTE WITH TIMING UNTIL THINGS IRON THEMSELVES OUT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 755 PM EDT SUN OCT 6 2013 LOW-LEVEL MOISTURE WRAPPING BACK INTO THE AREA BEHIND EXITING LOW PRES SHOULD RESULT IN IFR CONDITIONS THIS EVENING AT KIWD...LIFR AT KCMX AND MVFR FALLING TO IFR THIS EVENING AT KSAW. EXPECT A FEW -SHRA AS WELL. PER SATELLITE/SFC OB TRENDS...EXPECT IMPROVEMENT TO MVFR FROM NW TO SE LATE EVENING AND OVERNIGHT...AND LOW CLOUDS MAY EVEN SCATTER OUT LATE AT KIWD/KCMX. MVFR CIGS SHOULD RETURN FOR A TIME MON MORNING AT KIWD/KCMX AS DAYTIME HEATING GENERATES STRATOCU. VFR CONDITIONS SHOULD THEN DEVELOP AT KIWD/KCMX EARLY IN THE AFTN AND AT KSAW AROUND MID AFTN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 409 PM EDT SUN OCT 6 2013 NNW WINDS AT 20 TO 30 KNOTS ARE EXPECTED TO DEVELOP LATE TONIGHT INTO MONDAY AS THE LOW PRES TROUGH OVER THE UPPER LAKES MOVES OFF TO THE EAST AND THE GRADIENT TIGHTENS ACROSS THE AREA. A HIGH PRESSURE RIDGE WILL THEN BUILD EAST INTO THE UPPER GREAT LAKES FOR MONDAY NIGHT WITH WINDS DROPPING BELOW 25KTS. AT THIS HIGH SHIFTS EAST ON WEDNESDAY...SOUTHERLY FLOW WILL DEVELOP OVER THE UPPER GREAT LAKES AS A LOW PRESSURE SYSTEM MOVES THROUGH CENTRAL CANADA. AT THIS TIME...THE SOUTHERLY FLOW LOOKS TO STAY BELOW 25KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MCD AVIATION...ROLFSON MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
410 PM EDT SUN OCT 6 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE WRN CONUS AND A TROUGH FROM HUDSON BAY INTO NRN ONTARIO. THE PERSISTENT MID/UPPER LEVEL LOW HAD EDGED EASTWARD INTO ERN IA. AT THE SFC...LOW PRES WAS LOCATED OVER S CNTRL LAKE SUPERIOR WITH A COLD FRONT INTO CNTRL LOWER MI AND A TROUGH TO THE SW INTO SE MN. RAIN ASSOCIATED WITH A WEAK SHORTWAVE IN THE WARM CONVEYOR AHEAD OF THE COLD FRONT WAS LIFTING NNE THROUGH ERN CWA. OTHERWISE...RADAR INDICATED ONLY VERY WEAK RETURNS OVER THE WEST WITH SOME SPRINKLES OR DRIZZLE. FARTHER WEST...A NARROW BAND OF RAIN TO NEAR DLH WAS ASSOCIATED WITH THE MID LEVEL DEFORMATION/FGEN BAND/TROWAL ON THE NRN FLANK OF THE MID LEVEL LOW. VIS LOOP SHOWED CLEARING OVER SRN UPPER MI WITH THE ADVANCING DRY SLOT. TONIGHT...MODELS SUGGEST THAT THE NE MN RAIN BAND WILL CONTINUE TO SLOWLY SPREAD INTO WEST UPPER MI THIS EVENING AND GRADUALLY SHRINK OVERNIGHT...PER FCST 310KE SURFACE. THERE MAY ALSO BE A FEW LIGHT SHOWERS THROUGH CNTRL UPPER MI THIS EVENING AS THE DRY SLOT AREA GIVES WAY TO INCREASING CLOUDS WITH INCREASING 700-300 MB QVECTOR CONV AND LOW LEVEL CONV NEAR THE TROUGH. IN ADDITION...SOME LAKE ENHANCED SHOWERS MAY DEVELOP OVERNIGHT AS 850 MB TEMPS DROP TO AROUND 1C WITH NNW LOW CYCLONIC FLOW INCREASING. SO...CHANCE POPS WERE MAINTAINED OVER MOST OF THE CWA TONIGHT EVEN IF ONLY INTERMITTENT PERIODS OF RAIN DEVELOP. MONDAY...THE REMAINING SYNOPTIC AND LAKE ENHANCED PCPN OVER THE EAST IS EXPECTED TO DIMINISH DURING THE MORNING AS THE MID LEVEL QVECTOR CONV FORCING AND DEEPER MOISTURE DEPART TO THE EAST. OTHERWISE...GRADUAL CLEARING AND SOME SUNSHINE DURING THE AFTERNOON WILL BRING TEMPS AGAIN TO NEAR SEASONAL NORMALS IN THE UPPER 50S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 QUIETER WEATHER WILL REPLACE THE UNSETTLED ACTIVITY OF THIS PAST WEEK STARTING MONDAY NIGHT. A 500MB RIDGE BUILDS ACROSS THE NORTHERN PLAINS BY 00Z TUESDAY...AND CONTINUES EASTWARD THROUGHOUT THE FORECAST PERIOD. SURFACE HIGH PRESSURE EXPANDS INTO THE GREAT LAKES DURING THE DAY TUESDAY...AND GRADUALLY CENTERS ITSELF OVER THE LOWER LAKES THROUGH FRIDAY AFTERNOON. THE ECMWF/GFS HAVE 925 MB TEMPS UP TO 14-15C FOR WEDNESDAY-FRIDAY AFTERNOON OUT WEST...WHICH PUTS HIGHS ROUGHLY IN THE UPPER 60S/NEAR 70. FOR THE REST OF THE AREA...EXPECT LOW TO MID 60S. BUMPED UP WINDS FOR TUESDAY AND WEDNESDAY TO ACCOUNT FOR TIGHTENING PRESSURE GRADIENT ACROSS UPPER MICHIGAN ASSOCIATED WITH THE SURFACE LOW MOVING JUST NORTH OF LAKE SUPERIOR AND HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES. THOUGH SOUTHERLY WINDS MAY GUST UP TO 20 KTS AND TEMPS WILL BE CLOSE TO 70...AFTERNOON RH WILL BE IN THE 35-40 PERCENT RANGE SO DO NOT EXPECT ANY FIRE WX CONCERNS. FRIDAY NIGHT INTO SUNDAY...A NEGATIVELY TILTED 500MB TROUGH/POSSIBLE CUT OFF LOW WILL DIVE INTO THE PLAINS. THIS WILL PROVIDE THE NEXT CHANCES FOR PRECIPITATION ACROSS UPPER MICHIGAN. RECENT MODEL RUNS HAVE THE SFC LOW PRESSURE SYSTEM MOVING NORTHEAST INTO HUDSON BAY BY SUNDAY MORNING...BRINGING A COLD FRONT ACROSS UPPER MI. BOTH THE GFS/ECMWF HAVE THIS...THOUGH THERE ARE DIFFERENCES IN TIMING...WITH THE GFS BRINGING THE FRONT THROUGH FRIDAY NIGHT AND THE ECMWF BRINGING IT THROUGH SATURDAY AFTERNOON. EVEN MORE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF SHOW UP ON SUNDAY AS ANOTHER TROUGH APPROACHES FROM THE WEST. THE GFS BRINGS SATURDAYS FRONT OUT OF UPPER MICHIGAN BY 12Z SUNDAY...AND THE DRY SLOT MOVES IN OVERHEAD WHICH ENDS PRECIPITATION. BY 00Z MONDAY IT HAS A SHORTWAVE SLIDING INTO THE DAKOTAS AND PRECIPITATION MOVING INTO WESTERN LAKE SUPERIOR OUT AHEAD OF IT. THE ECMWF KEEPS A STRONGER RIDGE OVER THE LOWER LAKES AND NEW ENGLAND STATES FOR SATURDAY AND SUNDAY...SO THE PROGRESSION OF THE FRONT ON SATURDAY IS SLOWER THAN THE GFS...AND IT STALLS OUT OVER CENTRAL/EASTERN UPPER MICHIGAN FOR SUNDAY. OVERALL...GENERAL CHANCE-SLIGHT CHANCE POPS ARE IN THE FORECAST FOR THESE DAYS. IT SEEMS BOTH MODELS HAVE BEEN FAIRLY INCONSISTENT FROM RUN TO RUN ON THE WEEKEND SOLUTION...SO WILL NOT GET CUTE WITH TIMING UNTIL THINGS IRON THEMSELVES OUT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 409 PM EDT SUN OCT 6 2013 IFR CONDITIONS ARE EXPECTED TO CONTINUE AT CMX WITH ABUNDANT LOW LEVEL MOISTURE OVER THE REGION AND UPSLOPE W TO NW FLOW. MVFR CIGS ARE EXPECTED THIS AFTERNOON AT IWD/SAW AS DRIER MOVES INTO THE AREA AND GREATER DAYTIME MIXING OCCURS. CIGS MAY THEN FALL BACK AGAIN IN THE LATE AFTERNOON AND EVENING AS LOW-LEVEL MOISTURE WRAPS BACK INTO THE AREA BEHIND SFC LOW MOVING EXITING TO THE E OF THE AREA. VFR CONDITIONS WILL MOVE IN WITH DRIER AIR INTO IWD AND CMX LATE TONIGHT AND INTO SAW BY MID MON MORNING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 409 PM EDT SUN OCT 6 2013 NNW WINDS AT 20 TO 30 KNOTS ARE EXPECTED TO DEVELOP LATE TONIGHT INTO MONDAY AS THE LOW PRES TROUGH OVER THE UPPER LAKES MOVES OFF TO THE EAST AND THE GRADIENT TIGHTENS ACROSS THE AREA. A HIGH PRESSURE RIDGE WILL THEN BUILD EAST INTO THE UPPER GREAT LAKES FOR MONDAY NIGHT WITH WINDS DROPPING BELOW 25KTS. AT THIS HIGH SHIFTS EAST ON WEDNESDAY...SOUTHERLY FLOW WILL DEVELOP OVER THE UPPER GREAT LAKES AS A LOW PRESSURE SYSTEM MOVES THROUGH CENTRAL CANADA. AT THIS TIME...THE SOUTHERLY FLOW LOOKS TO STAY BELOW 25KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MCD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1023 PM CDT SUN OCT 6 2013 .UPDATE... ISSUED AT 1017 PM CDT SUN OCT 6 2013 SOME PATCHY RADIATIONAL FOG HAS DEVELOPED OVER THE ARROWHEAD OF MINNESOTA. DEWPOINT DEPRESSIONS AROUND SUNSET WERE LESS THAN 10 DEGREES FOR MOST OF THE FORECAST AREA...EXCEPT FOR THE FAR NORTHWEST COUNTIES. THEN...AS OF 9PM SOME DRIER AIR HAD FILTERED IN FROM THE NORTHWEST AND THE BETTER DEWPOINT DEPRESSIONS REMAIN IN THE SAME AREAS. HAVE PUT IN PATCHY TO AREAS OF FOG INTO THE GRIDS FOR THE REST OF THE NIGHT FOR A FAIRLY LARGE PORTION OF THE FORECAST AREA...AND AM ALSO IN THE PROCESS OF UPDATING TERMINAL FORECASTS AS WELL. UPDATE ISSUED AT 641 PM CDT SUN OCT 6 2013 SOME MINOR ADJUSMENTS TO EVENING FORECAST...MAINLY FOR CLOUD TRENDS AND TEMPERATURES FOR THE NEXT FEW HOURS. HAVE SOME CONCERNS FOR THE RECENT RAINFALL SETTING UP GOOD PRECONDITIONS FOR FOG...WITH PLENTY OF LOW LEVEL MOISTURE AND LIGHT NORTHWEST WINDS. CURRENTLY GUIDANCE INDICATES NO FOG IS LIKELY TO FORM. EXPERIENCE BEGS TO DIFFER. FOR NOW WILL MONITOR LOW LEVEL MOISTURE PARAMETERS AND WINDS...AND RE-EVALUATE HERE BEFORE 10 PM. ALSO UPDATED AVIATION SECTION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 MID LEVEL DEFORMATION ZONE EVIDENT ON SATELLITE AND RADAR ACROSS THE CWA. A LINE OF LIGHT RAIN/DRIZZLE EXTENDED FROM THE ARROWHEAD THROUGH AITKIN INTO SOUTHWEST MINNESOTA. THE HRRR HAS BEEN SHOWING THIS BAND DEVELOPING TODAY...BUT WAS A BIT TOO STRONG AND SLOW WITH IT. WE HAVE CHANCE FOR RAIN OVER OUR FAR EASTERN MN CWA AND NORTHWEST WISCONSIN THIS EVENING...AND DIMINISH OVERNIGHT. ANY RAINFALL SHOULD BE RATHER LIGHT...FROM A TRACE TO A COUPLE HUNDREDTHS OF AN INCH. CLEARING WAS ALSO WORKING INTO OUR WESTERN CWA...AND THAT SHOULD CONTINUE AS WELL THROUGH THE NIGHT. WE DO DECREASE SKY COVER TO CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH LOWS IN THE MID THIRTIES TO AROUND FORTY. WE DO NOT EXPECT WINDS TO DECOUPLE OVER A LARGE AREA...BUT A FEW FAVORED LOCATIONS LIKELY WILL SUCH AS KHIB/KBFW AND WE LOWERED TEMPS A BIT MORE THERE. SURFACE HIGH PRESSURE WILL LEAD TO PARTLY TO MOSTLY SUNNY SKIES MONDAY WITH TEMPERATURES WARMING INTO THE UPPER FIFTIES TO LOWER SIXTIES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 THE WESTERN GREAT LAKES REGION WILL BE SITUATED BETWEEN THE DEPARTING RIDGE AND AN APPROACHING NEGATIVELY TILTED LONG WAVE TROUGH THROUGH THE TUESDAY-FRIDAY TIME FRAME. THIS WILL RESULT IN AN INCREASING SW FLOW WITH A RETURN TO UNSEASONABLY WARM H92-H85 TEMPS BY MID WEEK. HAVE INCREASED THE SOUTH WINDS TUESDAY AS LATEST MODEL RUNS ARE IN GOOD AGREEMENT THAT A 40-50 KT LLJ PUSHES OVER MINNESOTA THROUGH TUESDAY AFTERNOON. LATEST NAM BUFR SOUNDINGS AT LOCATIONS ACROSS THE DLH CWA SHOW WINDS AROUND 35 KT IN THE MIX LAYER TUESDAY AFTERNOON AS TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 60 TO LOW 70S. HOWEVER...HIGHER GUSTS TO 40 KT ARE NOT OUT OF THE QUESTION IF TEMPERATURES WARM JUST A FEW DEGREES HIGHER ALLOWING FOR DEEPER MIXING. RAIN CHANCES RETURN TO THE FCST FRIDAY NIGHT/SATURDAY AS A STRONG VORT MAX /WITH CLOSED H85-H50 LOW/ ROUNDS THE BASE OF THE LONG WAVE TROUGH AND LIFTS INTO THE UPPER MIDWEST. THIS LOW WILL BRING CLOUDS AND ONGOING RAIN CHANCES TO THE NORTHLAND THROUGH MUCH OF THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 641 PM CDT SUN OCT 6 2013 LIFR CIGS AT KDLH AND KHYR TO CLEAR BY 03Z THIS EVENING...LEAVING VFR CONDITIONS AND LIGHT NORTHWEST WINDS AT THE TERMINALS THE REST OF THE NIGHT. HAVE CONCERNS FOR FOG POTENTIAL AS MENTIONED IN UPDATE SECTION ABOVE...AND WILL MAKE ADJUSTMENTS AS NEEDED. VFR CONDITIONS TO CONTINUE THROUGH TOMORROW...WITH WINDS REMAINING NORTHWEST AT OR BELOW 10 KTS THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 36 60 42 67 / 10 0 0 0 INL 35 61 41 69 / 0 0 0 0 BRD 38 64 44 72 / 0 0 0 0 HYR 36 61 39 70 / 30 10 0 0 ASX 38 61 43 70 / 30 10 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...LE SHORT TERM...MELDE LONG TERM...GRANING AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
644 PM CDT SUN OCT 6 2013 .UPDATE... ISSUED AT 641 PM CDT SUN OCT 6 2013 SOME MINOR ADJUSMENTS TO EVENING FORECAST...MAINLY FOR CLOUD TRENDS AND TEMPERATURES FOR THE NEXT FEW HOURS. HAVE SOME CONCERNS FOR THE RECENT RAINFALL SETTING UP GOOD PRECONDITIONS FOR FOG...WITH PLENTY OF LOW LEVEL MOISTURE AND LIGHT NORTHWEST WINDS. CURRENTLY GUIDANCE INDICATES NO FOG IS LIKELY TO FORM. EXPERIENCE BEGS TO DIFFER. FOR NOW WILL MONITOR LOW LEVEL MOISTURE PARAMETERS AND WINDS...AND RE-EVALUATE HERE BEFORE 10 PM. ALSO UPDATED AVIATION SECTION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 MID LEVEL DEFORMATION ZONE EVIDENT ON SATELLITE AND RADAR ACROSS THE CWA. A LINE OF LIGHT RAIN/DRIZZLE EXTENDED FROM THE ARROWHEAD THROUGH AITKIN INTO SOUTHWEST MINNESOTA. THE HRRR HAS BEEN SHOWING THIS BAND DEVELOPING TODAY...BUT WAS A BIT TOO STRONG AND SLOW WITH IT. WE HAVE CHANCE FOR RAIN OVER OUR FAR EASTERN MN CWA AND NORTHWEST WISCONSIN THIS EVENING...AND DIMINISH OVERNIGHT. ANY RAINFALL SHOULD BE RATHER LIGHT...FROM A TRACE TO A COUPLE HUNDREDTHS OF AN INCH. CLEARING WAS ALSO WORKING INTO OUR WESTERN CWA...AND THAT SHOULD CONTINUE AS WELL THROUGH THE NIGHT. WE DO DECREASE SKY COVER TO CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH LOWS IN THE MID THIRTIES TO AROUND FORTY. WE DO NOT EXPECT WINDS TO DECOUPLE OVER A LARGE AREA...BUT A FEW FAVORED LOCATIONS LIKELY WILL SUCH AS KHIB/KBFW AND WE LOWERED TEMPS A BIT MORE THERE. SURFACE HIGH PRESSURE WILL LEAD TO PARTLY TO MOSTLY SUNNY SKIES MONDAY WITH TEMPERATURES WARMING INTO THE UPPER FIFTIES TO LOWER SIXTIES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 THE WESTERN GREAT LAKES REGION WILL BE SITUATED BETWEEN THE DEPARTING RIDGE AND AN APPROACHING NEGATIVELY TILTED LONG WAVE TROUGH THROUGH THE TUESDAY-FRIDAY TIME FRAME. THIS WILL RESULT IN AN INCREASING SW FLOW WITH A RETURN TO UNSEASONABLY WARM H92-H85 TEMPS BY MID WEEK. HAVE INCREASED THE SOUTH WINDS TUESDAY AS LATEST MODEL RUNS ARE IN GOOD AGREEMENT THAT A 40-50 KT LLJ PUSHES OVER MINNESOTA THROUGH TUESDAY AFTERNOON. LATEST NAM BUFR SOUNDINGS AT LOCATIONS ACROSS THE DLH CWA SHOW WINDS AROUND 35 KT IN THE MIX LAYER TUESDAY AFTERNOON AS TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 60 TO LOW 70S. HOWEVER...HIGHER GUSTS TO 40 KT ARE NOT OUT OF THE QUESTION IF TEMPERATURES WARM JUST A FEW DEGREES HIGHER ALLOWING FOR DEEPER MIXING. RAIN CHANCES RETURN TO THE FCST FRIDAY NIGHT/SATURDAY AS A STRONG VORT MAX /WITH CLOSED H85-H50 LOW/ ROUNDS THE BASE OF THE LONG WAVE TROUGH AND LIFTS INTO THE UPPER MIDWEST. THIS LOW WILL BRING CLOUDS AND ONGOING RAIN CHANCES TO THE NORTHLAND THROUGH MUCH OF THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 641 PM CDT SUN OCT 6 2013 LIFR CIGS AT KDLH AND KHYR TO CLEAR BY 03Z THIS EVENING...LEAVING VFR CONDITIONS AND LIGHT NORTHWEST WINDS AT THE TERMINALS THE REST OF THE NIGHT. HAVE CONCERNS FOR FOG POTENTIAL AS MENTIONED IN UPDATE SECTION ABOVE...AND WILL MAKE ADJUSTMENTS AS NEEDED. VFR CONDITIONS TO CONTINUE THROUGH TOMORROW...WITH WINDS REMAINING NORTHWEST AT OR BELOW 10 KTS THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 39 60 42 67 / 10 0 0 0 INL 37 61 41 69 / 0 0 0 0 BRD 39 64 44 72 / 0 0 0 0 HYR 39 61 39 70 / 30 10 0 0 ASX 42 61 43 70 / 30 10 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...LE SHORT TERM...MELDE LONG TERM...GRANING AVIATION...LE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
353 PM CDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 315 PM CDT SAT OCT 5 2013 OCCLUDED AND VERTICALLY STACKED LOW WAS SPINNING OVER SOUTHEAST SODAK THIS AFTERNOON. AN OCCLUDED FRONT AT THE SFC STRETCHES FROM NEAR AXN...DOWN TO THE NRN TWIN CITIES METRO AND SOUTHEAST FROM THERE TO A TRIPLE POINT IN SW WISCONSIN. THIS LOW HAS STARTED TO SLIP ESE TOWARD SW MN THIS AFTERNOON. THIS IS ALLOWING THE BLIZZARD THAT HAS BEEN RAGING FOR THE BETTER PART OF 3 DAYS ACROSS THE NRN HIGH PLAINS TO SLOWLY WIND DOWN TODAY...WITH AN IMPRESSIVE BANK OF SNOW SHOWING UP ON VIS SATELLITE THIS AFTERNOON ACROSS WYOMING INTO WRN NEB/SODAK. .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 315 PM CDT SAT OCT 5 2013 STRONG MID LEVEL JET HAS ROUNDED THE BASE OF THE STACKED LOW OVER SODAK TODAY. THIS HAS HELPED ENHANCE MID-LEVEL TEMP GRADIENTS ACROSS THE AREA. THIS HAS RESULTED IN AN ENHANCED AREA OF FGEN DEVELOPING IN THE H7 TO H5 LAYER...MIX IN SOME ADIABATIC OMEGA ON THE 305K SFC AND YOU GET THE DEVELOPING BAND OF SHOWERS ACROSS THE TWIN CITIES METRO AT 300 PM. THE HRRR ALONG WITH THE HOPWRF HAVE BEEN CONSISTENT IN DEVELOPING THIS FEATURE ALL DAY...SO FOLLOWED THESE MODELS CLOSELY TO MOVE THIS BAND OF PRECIP THROUGH ERN AND CENTRAL MN AND WRN WI THIS EVENING INTO TONIGHT. STILL HAVE BEST LI/S BETWEEN 0 AND -2 OVER WRN WI..SO HAVE SOME ISO THUNDER WORDING IN THE EAST THIS AFTERNOON. THIS ALSO MATCHES UP WELL WITH WHERE THE HRRR IS DEVELOPING MORE ROBUST CONVECTION. THOUGH WE ARE NOT EXPECTING ANY SEVERE WEATHER...COOLER TEMPERATURES ALOFT MOVING IN FROM THE SOUTHWEST HAS RESULTED IN SOME GRAUPEL/SMALL HAIL BEING REPORTED THIS AFTERNOON...WHICH WILL CONTINUE TO BE THE CASE THROUGH THIS EVENING BEFORE WE LOOSE THE CONVECTIVE ASPECT OF THE PRECIP AND IT BECOMES MAINLY STRATIFORM. FOR TONIGHT...THE BIG QUESTION IS WHETHER OR NOT SKIES TRY TO CLEAR OUT AGAIN ACROSS THE SOUTH AS THE DEVELOPING PRECIP BAND MOVES INTO CENTRAL MN AND NW WI. TO SOME EXTENT...THE NAM/ECMWF/GFS ALL SHOW SKIES CLEARING OUT TONIGHT FOR AT LEAST A PERIOD FROM SRN MN INTO WRN WI. THE NAM IS THE MOST AGGRESSIVE WITH THIS...WITH LOWS DOWN INTO THE 30S FROM SOUTH CENTRAL MN UP INTO WRN WI. BESIDE THE COOLER TEMPS...IF SKIES DO CLEAR OUT LIKE THAT...THEN THOSE CLEAR SKIES WOULD LIKELY FILL IN WITH DENSE FOG...SO THAT WILL NEED TO BE WATCHED AS WE GO THROUGH THE NIGHT. FOR SUNDAY...THINGS ARE LOOKING UP WEATHER WISE FOR THE TWIN CITIES MARATHON IN THE MORNING...AS PRECIP LOOKS TO HOLD OFF IN THE TWIN CITIES UNTIL THE AFTERNOON. BY 12Z THE LOW WILL HAVE FILLED IN TO THE POINT WHERE IT WILL BE A RATHER BROAD AREA OF LOW PRESSURE EXTENDING FROM SW MN UP INTO THE WRN UP OF MICH. COLD CONVEYOR BELT PRECIP BY SUNDAY MORNING WILL STRETCH ACROSS NRN WI ACROSS CENTRAL/NRN MN...THEN DOWN ACROSS THE ERN DAKOTAS...ALMOST WRAPPING AROUND THE MPX AREA. AS SFC AND UPPER AIR FEATURES DRIFT TOWARD THE GREAT LAKES DURING THE DAY...THE WRN EDGE OF THE PRECIP WILL BEGIN MOVING ACROSS THE AREA. USED A BLEND OF THE GEM/NAM/SREF TO BRING THIS PRECIP BACK EAST ACROSS THE AREA SUNDAY...THIS RESULTED IN A SLOWING OF THE EWD PROGRESSION OF POPS TOMORROW. IN FACT...MOST OF THE 12Z GUIDANCE KEEPS PRECIP THROUGH 7 PM SUNDAY EVENING WEST OF WISCONSIN...SO A FURTHER SLOWING IN POP GRIDS MAY BE NEEDED TONIGHT. OTHER CHANGE FOR SUNDAY WAS TO LOWER TEMPS A BIT...ESPECIALLY ACROSS MN. WITH MOSTLY CLOUDY CONDITIONS EXPECTED TO PREVAIL...WILL BE A STRUGGLE FOR MUCH OF THE MN AREA TO CRACK 50 FOR HIGHS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CDT SAT OCT 5 2013 AS THE SHORT TERM MENTIONED...THE UPPER LOW CONTINUES TO SLOW AND LOW POPS REMAIN IN PLACE OVER ERN/SRN MN AND WRN WI INTO SUNDAY NIGHT. CLEARING WILL GRADUALLY TAKE PLACE AND IT IS POSSIBLE TO GET AREAS OF FOG BY MONDAY MORNING DEPENDING ON TIMING OF CLEARING AND STRENGTH OF WIND. ANOTHER LONG STRETCH OF LATE SUMMER WEATHER WILL TAKE HOLD NEXT WEEK...PARTICULARLY TUESDAY ONWARD AS A DIGGING WEST COAST TROUGH LEADS TO A LARGE RIDGE BUILDING EASTWARD ACROSS THE PLAINS. STRONG RETURN FLOW AND GUSTY SOUTH WINDS TUESDAY WILL EASE MID/LATE WEEK AS A BAGGIER PRESSURE PATTERN DEVELOPS UNDER THE RIDGE. 925 MB TEMPS REACH THE MID/UPPER TEENS CELSIUS FOR MUCH OF NEXT WEEK...BRINGING HIGHS FIRMLY INTO THE 70S. GUIDANCE IS IN STRONG AGREEMENT FOR MID 70S...INCLUDING THE CLIMATOLOGICALLY FAVORING MOS PRODUCT AT EXTENDED RANGES. HIGHS AND LOWS WILL BE ABOUT 15 DEGREES ABOVE AVERAGE WITH NEARLY UNRESTRICTED SUNSHINE EACH DAY THROUGH THURSDAY. ANOTHER POTENT STORM SYSTEM WILL DEVELOP TO THE LEE OF THE ROCKIES THURSDAY NIGHT AND TRACK NORTHWARD INTO THE DAKOTAS FRIDAY NIGHT. THIS SHOULD KEEP THE MAJORITY OF THE AREA DRY THROUGH FRIDAY BEFORE THE COLD FRONT SWINGS THROUGH FRIDAY NIGHT. OVERALL...THE GFS AND ECMWF REMAIN IN RATHER GOOD AGREEMENT SO FORECAST CONFIDENCE IS HIGH THROUGHOUT THE LONG TERM PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT OCT 5 2013 LOW CONFIDENCE WITH CIG FORECAST IN TAFS. DRYING ASSOCIATED WITH OCCLUDED LOW OVER SE SODAK HAS BEEN SLOWLY SPREADING NORTH/EAST. THE RAP ALONG WITH THE GFS/NAM TAKES VFR CONDITIONS ACROSS ALL TERMINALS FOR A TIME. THERE IS LOTS OF DISAGREEMENT WITH WHEN MVFR CIGS WILL DROP BACK SOUTH AND EAST THIS EVENING...WITH RAP BEING THE MOST AGGRESSIVE WITH BRINGING MVFR OR LOWER CIGS BACK AND THE GFS/NAM SIGNIFICANTLY SLOWER. THESE TAFS WERE WRITTEN MORE TOWARD THE GFS/NAM IDEA FOR CIGS. CONFIDENCE INCREASING IN AN AREA OF SHRA DEVELOPING SHORTLY FROM STC DOWN TO MKT ON EAST FOR THE AFTERNOON. THE HRRR ALONG WITH THE HOPWRF HAVE BOTH BEEN DEPICTING THIS ALL MORNING AND WITH MID LEVEL CLOUDS EXPANDING ON SATELLITE ALONG WITH RETURNS SHOWING UP ON RADAR IN SOUTH CENTRAL MN...SIDED CLOSELY WITH THE HRRR IN BRINGING PRECIP BACK TO ALL BUT RWF. THE LOW OFF TO THE WEST WILL DRIFT ACROSS MN TONIGHT...WITH WINDS BECOMING LIGHT AND VRB AS A RESULT. WITH THE LIGHT WINDS... ANYWHERE THAT REMAINS RELATIVELY CLEAR TONIGHT WILL HAVE TO THREAT FOR DENSE FOG. AT THE MOMENT...THE MOST LIKELY PLACE FOR THAT TO HAPPEN WOULD BE OVER WRN WI. KMSP...TOUGH TO PIN DOWN THE CIGS FOR THIS FORECAST...AS THE 12Z NAM/GFS WOULD BOTH INDICATE THAT CIGS WILL REMAIN VFR UNTIL LATE SUNDAY AFTERNOON. CONFIDENCE HIGH IN ANOTHER ROUND OF SHOWERS MOVING ACROSS THE FIELD BETWEEN 20Z AND 01Z PER THE HRRR AND HOPWRF...THOUGH CONFIDENCE LOWER IN CIGS COMING BACK DOWN AS LOW AS THEY ARE CURRENTLY FORECAST TO BE...MAY ONLY COME AS LOW AS 6K FT WITH THE PRECIP. OPTIMISTIC CIG FORECAST TOMORROW BASED ON THE GFS/NAM...BUT THE RAP SHOWS MVFR CIGS RETURNING TO MSP AROUND 09Z. IF THE CIGS DO COME IN BEFORE 12Z SUNDAY...THERE IS A GOOD CHANCE THEY WILL COME IN BELOW 017. /OUTLOOK FOR KMSP/ MON...VFR...MVFR POSSIBLE EARLY. WINDS NW 5-10 KT. TUE...VFR. WINDS S 15G25 KT. WED...VFR. WINDS SSE 10-15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SYNOPSIS...MPG SHORT TERM...MPG LONG TERM...BORGHOFF AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
320 PM CDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 319 PM CDT SAT OCT 5 2013 STACKED LOW PRESSURE OVER SOUTHEAST SOUTH DAKOTA WILL MOVE EAST/SOUTHEAST TONIGHT...ALTHOUGH THE SURFACE LOW IS FORECAST TO MOVE TOWARD UPPER MICHIGAN TONIGHT. AS THE SURFACE LOW NEARS THE NORTHLAND LATER TONIGHT...WINDS SHOULD GRADUALLY SUBSIDE. WE CONTINUE TO GET GUSTS OF 35 TO 45 MPH AT THE HEAD OF LAKE SUPERIOR...AND WE`LL EXTEND THE WIND ADVISORY FOR DOUGLAS...SOUTHERN SAINT LOUIS...CARLTON...AND SOUTHERN LAKE COUNTIES UNTIL 10 PM. THE STRONGEST WINDS WILL REMAIN WILL BE CLOSE TO LAKE SUPERIOR. RAIN WAS DEVELOPING ACROSS PORTIONS OF CENTRAL/SOUTHEAST MINNESOTA SIMILAR TO WHAT THE MODELS INCLUDING THE HRRR WERE DEPICTING. WE SHOULD CONTINUE TO SEE RAIN DEVELOP AND MOVE NORTH THROUGH THE NORTHLAND THIS EVENING/OVERNIGHT...BECOMING WIDESPREAD. WE`VE SEEN A FEW LIGHTNING STRIKES CLOSE TO THE AREA...SO ADDED A SLIGHT CHANCE FOR A STORM TO ALL AREAS LATE THIS AFTERNOON/EARLY EVENING...THEN TO EASTERN AREAS THROUGH LATE EVENING. SOME FOG WILL ALSO BE POSSIBLE...ESPECIALLY AROUND THE LAKE AND AS THE GRADIENT RELAXES. THERE WILL BE A CONTINUED CHANCE FOR SHOWERS ON SUNDAY...ALTHOUGH COVERAGE WILL BE LESS THAN WHAT HAS OCCURRED TODAY AND WHAT IS EXPECTED TONIGHT. THERE SHOULD STILL BE PLENTY OF CLOUDS AROUND THOUGH...AND THE MODELS CONTINUE TO SHOW PLENTY OF LOW LEVEL MOISTURE REMAINING. THE EXCEPTION WILL BE PORTIONS OF OUR SOUTHEAST ZONES EARLY...AND OUR FAR NORTHWEST ZONES LATE. HIGHS SUNDAY WILL RANGE FROM 55 TO 60 OVER OUR WESTERN/SOUTHEAST ZONES...WITH AREAS BETWEEN AROUND 50. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 319 PM CDT SAT OCT 5 2013 TAIL END OF A DEPARTING LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL ALLOW A FEW LIGHT RAIN SHOWERS TO LINGER ACROSS THE ERN HALF OF THE FORECAST AREA SUNDAY NIGHT INTO EARLY MONDAY MORNING. RAINFALL AMTS WILL BE LOW. HIGH PRESSURE WILL BUILD IN ACROSS THE UPPER MIDWEST MONDAY AND TUESDAY WITH QUIET WEATHER CONDITIONS AND WARMER TEMPERATURES. SKIES WILL REMAIN MOSTLY SUNNY EARLY IN THE WEEK BEFORE A WEAK SFC FRONT SLIDES ACROSS THE NRN PLAINS AND USHERS IN ADDITIONAL CLOUD COVER WED AND THURSDAY...MAINLY OVER THE NRN COUNTIES. THE UPPER RIDGE OVER THE ERN US WILL AMPLIFY LATE IN THE WEEK AS A TROUGH IN THE WEST DEEPENS THROUGH THE ROCKIES. THIS UPPER LOW WILL EVENTUALLY MOVE INTO THE MIDWEST BY THE WEEKEND AND BRING ADDITIONAL CHANCES FOR PRECIPITATION. TEMPERATURES WILL REMAIN ABOVE AVERAGE THIS WEEK WITH VERY MILD AFTERNOON HIGHS IN THE 60S AND LOWER 70S. OVERNIGHT LOWS EARLY IN THE WEEK WILL BE SLIGHTLY CHILLY INTO THE 30S AND LOWER 40S...BUT RISE INTO THE UPPER 40S AND LOWER 50S BY THE LATTER HALF OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1232 PM CDT SAT OCT 5 2013 IFR AND MVFR CIGS/VSBYS WILL PERSIST THROUGH TODAY AND MOST OF TONIGHT BEFORE GRADUAL IMPROVEMENT IS SEEN BY LATE SUNDAY MORNING ACROSS THE WRN TERMINALS. LIGHT SCATTERED RAIN SHOWERS ARE EXPECTED THIS AFTERNOON WITH MORE WIDESPREAD HEAVIER SHOWERS POSSIBLE THIS EVENING...AFTER 23/00Z...LASTING THROUGH 05/06Z. VSBYS WILL LOWER IN THE STRONGER SHOWERS...WITH POSSIBLY PATCHY FOG AROUND DLH AND HYR TONIGHT. GUSTY NE WINDS WILL SLOWLY DIMINISH IN INTENSITY AND BACK TO THE NORTH TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 47 51 40 62 / 90 60 20 10 INL 39 55 37 62 / 60 40 0 0 BRD 46 51 39 65 / 80 60 10 0 HYR 46 56 40 61 / 80 50 30 10 ASX 49 54 43 62 / 80 60 40 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ020-037. WI...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR WIZ001. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR LSZ121-140-148. && $$ SHORT TERM...MELDE LONG TERM...BJT AVIATION...BJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
111 PM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1034 AM CDT SAT OCT 5 2013 A TRICKY FORECAST TO SAY THE LEAST FOR TODAY. DRY SLOT HAS MOVED IN BEHIND THE OCCLUDED FRONT THIS MORNING...WITH PARTIAL CLEARING OF SKIES SEEN WEST AND SOUTH OF THE TWIN CITIES. AFTER MAKING GOOD PROGRESS OVERNIGHT...THIS CLEARING HAS PUT ON THE BREAKS AS THE LOW OVER SE SODAK HAS STARTED TO DRIFT ESE. THIS WILL KEEP THE CLEARING FROM MAKING IT MUCH FARTHER NORTH...BUT IT WILL CONTINUE TO SLOWLY CRAWL TOWARD THE EAST TODAY. OF COURSE AS THIS IS GOING ON THE BIGGEST CHANGE TO THE FORECAST IS THE ADDITION OF SHOWERS THIS AFTERNOON FROM MANKATO TO ST. CLOUD ON EAST. THE HRRR HAS BEEN SHOWING THIS AREA OF SHOWERS DEVELOPING BACK TO THE WEST FOR SEVERAL RUNS NOW. LOOKING AT THE RAP...THIS IS IN RESPONSE TO A STRONG BAND OF FGEN COMING UP FROM IOWA IN THE H7-H5 LAYER. LOOKING DOWN TO THE SOUTHWEST ON SATELLITE...YOU CAN SEE THIS AREA OF PRECIP STARTING TO TAKE SHAPE FROM ERN KANSAS UP INTO WRN IOWA. BOOSTED POPS UP TO AROUND 50 PERCENT BACK TO THE CITIES THIS AFTERNOON...BUT IF THE HRRR IS CORRECT...MAY NEED TO BOOST THEM UP SIGNIFICANTLY IN THE NEAR FUTURE...ESPECIALLY CONSIDERING ALL 4 MEMBERS OF THE 05.09 HOPWRF SHOW SOMETHING SIMILAR HAPPENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE POTENCY OF THIS EARLY FALL SYSTEM WAS AGAIN ON DISPLAY LAST NIGHT WITH STRONG TO SEVERE STORMS IN THE WARM SECTOR AND A RAGING BLIZZARD IN WESTERN SOUTH DAKOTA. FURTHERMORE...THE SYSTEM HAS BEEN OCCLUDED FOR 12-18 HOURS NOW AND WE STILL SAW A 1-2 MB MSLP PRESSURE DROP OVERNIGHT. THE TROWAL IS CREATING A HOME RUN HITTING DEFORMATION BAND FROM NORTHERN MN TO ND TO SD. IN FACT...THE PRECIP SHIELD ALONG THE COLD CONVEYOR BELT ACTUALLY EXTENDS ALL THE WAY FROM WYOMING TO MICHIGAN...AND THUNDERSTORMS ALONG THE COLD FRONT EXTEND FROM MICHIGAN TO TEXAS. NOT A SMALL SYSTEM BY ANY MEANS. THE FORECAST AREA WILL FIND ITSELF IN THE DRY SLOT MOST OF THE DAY TODAY AND ALSO TONIGHT TO SOME DEGREE. HOWEVER SOME DRIZZLE IS POSSIBLE AND THE CLOUDS SHOULD LARGELY STAY IN TACT. THE OCCLUDED BOUNDARY ISN`T GOING ANYWHERE...ESPECIALLY FOR CENTRAL MN/WI. SOUTHERN PORTIONS OF THE FORECAST AREA /THAT`S RIGHT...SOUTHERN/ ARE CLOSER TO THE COLDER AND DRIER AIR...SO THERE IS A BETTER CHANCE OF AT LEAST PARTIAL CLEARING TODAY IN SOUTHERN MN. MUCH COLDER AIR ALOFT ARRIVES TONIGHT...SO THE STRATUS WON`T BE FAR BEHIND EVEN IF THERE IS CLEARING DURING THE DAY TODAY. THE 00-06Z GUIDANCE IS TOO FAR SOUTH WITH THE DEFORMATION PRECIP BAND THIS MORNING...AS THE FORECAST AREA IS VIRTUALLY PRECIP FREE. IT`S ALSO NOT DEEP ENOUGH WITH THE SURFACE LOW. TRIED TO KEEP THE POPS TODAY ON THE OUTER EDGES OF THE FORECAST AREA TO COUNTER THIS AND ALSO TO STAY CLOSE TO SURROUND FORECAST OFFICES. OTHERWISE...WINDS WILL FALL OFF AS THE LOW SLOWLY FILLS AND MOVES OVERHEAD. IF THE CLOUDS CLEAR ANYWHERE TONIGHT...FOG COULD BE A PROBLEM...TOOK THE SIDE OF LOW STRATUS FOR NOW. NEAR STEADY TEMPERATURE TODAY SO MADE LITTLE ADJUSTMENT TO THE PREVIOUS FORECAST. WE ADJUSTED DEWPOINTS BY KEEPING SLIGHTLY HIGHER VALUES NEAR THE FRONT AND COOLER VALUES CLOSER TO THE DRY SLOT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE SFC LOW FROM THE POTENT/DEEP SYSTEM AFFECTING THE REGION WILL SHIFT INTO WI BY DAYBREAK SUN MRNG WHILE THE LOW PRES CENTER ALOFT WILL SHIFT SE INTO NRN IA. AS THESE TWO LOWS MOVE EAST IN TANDEM SLOWLY DURG THE DAY ON SUN...THE DRY SLOT OVER MUCH OF THE AREA WILL FILL BACK IN WITH DEEPER MOISTURE WRAPPING AROUND THE UPPER LEVEL LOW. COLD ALOFT COMBINED WITH LOW LEVEL WINDS SHIFTING TO A MORE NLY DIRECTION WILL AID IN KEEPING LOW CLOUDS IN PLACE FOR MUCH OF THE DAY...ALONG WITH A DRIZZLE/RAIN SCENARIO FOR SENSIBLE WX. THE UPPER LOW WILL SHIFT ESE INTO CENTRAL IL BY MON MRNG...DRAGGING MUCH OF THE MOISTURE WITH IT BUT THERE WILL STILL BE A CHC FOR LINGERING SHOWERS IN WRN WI ON MON WHILE SRN/CENTRAL MN STARTS TO CLEAR OUT. CONDS WILL GRADUALLY IMPROVE DURG THE DAY ON MON AS HIGH PRES FROM SW CANADA DROPS IN. DESPITE THE COOL ORIGIN OF THIS AIRMASS...IT WILL BE QUICKLY MODIFIED BY AN UPPER LEVEL RIDGE THAT WITH INCRG H5 HEIGHTS WILL SPELL A WARMING TREND ALONG WITH A PROLONGED DRYING-OUT PERIOD FOR THE AREA. DRY WX IS FORECAST MON THRU THU WITH HIGHS RISING BACK INTO THE MID 70S. MODELS CONTINUE TO ADVERTISE ANOTHER POTENT SYNOPTIC-SCALE LOW PRES SYSTEM TO DEVELOP IN THE LEE OF THE ROCKIES THU NIGHT INTO FRI MORNING...WITH IT QUICKLY MOVG NEWD INTO THE DAKOTAS FRI. THIS MAY ALLOW FOR SOME MID-TO-LATE DAY SHWRS/TSTMS OVER WRN MN ON FRI AS THIS SYSTEM ADVANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT OCT 5 2013 LOW CONFIDENCE WITH CIG FORECAST IN TAFS. DRYING ASSOCIATED WITH OCCLUDED LOW OVER SE SODAK HAS BEEN SLOWLY SPREADING NORTH/EAST. THE RAP ALONG WITH THE GFS/NAM TAKES VFR CONDITIONS ACROSS ALL TERMINALS FOR A TIME. THERE IS LOTS OF DISAGREEMENT WITH WHEN MVFR CIGS WILL DROP BACK SOUTH AND EAST THIS EVENING...WITH RAP BEING THE MOST AGGRESSIVE WITH BRINGING MVFR OR LOWER CIGS BACK AND THE GFS/NAM SIGNIFICANTLY SLOWER. THESE TAFS WERE WRITTEN MORE TOWARD THE GFS/NAM IDEA FOR CIGS. CONFIDENCE INCREASING IN AN AREA OF SHRA DEVELOPING SHORTLY FROM STC DOWN TO MKT ON EAST FOR THE AFTERNOON. THE HRRR ALONG WITH THE HOPWRF HAVE BOTH BEEN DEPICTING THIS ALL MORNING AND WITH MID LEVEL CLOUDS EXPANDING ON SATELLITE ALONG WITH RETURNS SHOWING UP ON RADAR IN SOUTH CENTRAL MN...SIDED CLOSELY WITH THE HRRR IN BRINGING PRECIP BACK TO ALL BUT RWF. THE LOW OFF TO THE WEST WILL DRIFT ACROSS MN TONIGHT...WITH WINDS BECOMING LIGHT AND VRB AS A RESULT. WITH THE LIGHT WINDS... ANYWHERE THAT REMAINS RELATIVELY CLEAR TONIGHT WILL HAVE TO THREAT FOR DENSE FOG. AT THE MOMENT...THE MOST LIKELY PLACE FOR THAT TO HAPPEN WOULD BE OVER WRN WI. KMSP...TOUGH TO PIN DOWN THE CIGS FOR THIS FORECAST...AS THE 12Z NAM/GFS WOULD BOTH INDICATE THAT CIGS WILL REMAIN VFR UNTIL LATE SUNDAY AFTERNOON. CONFIDENCE HIGH IN ANOTHER ROUND OF SHOWERS MOVING ACROSS THE FIELD BETWEEN 20Z AND 01Z PER THE HRRR AND HOPWRF...THOUGH CONFIDENCE LOWER IN CIGS COMING BACK DOWN AS LOW AS THEY ARE CURRENTLY FORECAST TO BE...MAY ONLY COME AS LOW AS 6K FT WITH THE PRECIP. OPTIMISTIC CIG FORECAST TOMORROW BASED ON THE GFS/NAM...BUT THE RAP SHOWS MVFR CIGS RETURNING TO MSP AROUND 09Z. IF THE CIGS DO COME IN BEFORE 12Z SUNDAY...THERE IS A GOOD CHANCE THEY WILL COME IN BELOW 017. /OUTLOOK FOR KMSP/ MON...VFR...MVFR POSSIBLE EARLY. WINDS NW 5-10 KT. TUE...VFR. WINDS S 15G25 KT. WED...VFR. WINDS SSE 10-15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...MPG SHORT TERM...CLF LONG TERM...JPC AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1232 PM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1232 PM CDT SAT OCT 5 2013 UPDATED FOR AVIATION DISCUSSION. UPDATE ISSUED AT 1029 AM CDT SAT OCT 5 2013 THE SURFACE LOW WAS LOCATED IN SOUTHEAST SOUTH DAKOTA AS OF 15Z WITH AN OCCLUDED FRONT EXTENDING FROM THIS LOW ACROSS PORTIONS OF S-C MINNESOTA INTO FAR SOUTHWEST WISCONSIN. 925MB BOUNDARY IS IN NEARLY THE SAME LOCATION WITH HIGHER THETA-E AIR NORTH AND EAST OF THE BOUNDARY. THIS FRONT MARKED A CLEARING LINE WITH DRY CONDITIONS BEHIND IT OVER MUCH OF SOUTHERN MINNESOTA. LIGHT RAIN/DRIZZLE CONTINUED OVER PORTIONS OF THE NORTHLAND THIS MORNING...BUT WASN`T REAL WIDESPREAD. WE TRIMMED BACK SOME ON POPS THROUGH MID AFTERNOON BUT MAY HAVE TO FURTHER AS SEVERAL OBSERVATIONS WERE NOT REPORTING ANY RAIN AS OF 15Z. WE DO EXPECT AN INCREASE IN COVERAGE LATER THIS AFTERNOON AS THE STACKED LOW PRESSURE SYSTEM MOVES FURTHER EAST. THE LATEST HRRR WAS DOING A DECENT JOB DEPICTING THE LIGHT RAIN THIS MORNING AND SHOWS COVERAGE INCREASING QUITE A BIT MID TO LATE AFTERNOON ACROSS THE SOUTHERN THIRD...THEN FURTHER NORTH THIS EVENING. THE 12Z NAM SUPPORTS THE HRRR BUT STILL MAY BE OVERDONE WITH IT`S QPF. AREAS OF DRIZZLE WILL ALSO OCCUR AROUND LAKE SUPERIOR. WE CONTINUE TO MONITOR RADAR TRENDS AND LATEST MODEL OUTPUT AND ADJUST AS NEEDED. IT REMAINS WINDY AROUND LAKE SUPERIOR...ESPECIALLY FROM SILVER BAY TO THE TWIN PORTS AND ALONG THE BAYFIELD PENINSULA. KDLH WAS GUSTING TO 42 MPH AS OF THE 1008 AM OBSERVATION AND TO 46 MPH ON PARK POINT. WE`LL KEEP THE WIND ADVISORY GOING AS IS FOR NOW. WE MAY NEED TO EXTEND IT FOR THE TWIN PORTS AREA TO TWO HARBORS/SILVER BAY. THE WIND WASN`T AS STRONG ACROSS BAYFIELD/ASHLAND COUNTIES BUT SOME HIGHER GUSTS WILL REMAIN POSSIBLE THERE AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 AT 4 AM...RAIN CONTINUED TO MOVE NORTHWARD ACROSS THE CWA. THE MASSIVE LOW PRESSURE SYSTEM WAS LOCATED IN CENTRAL SOUTH DAKOTA...WITH AN OCCLUDED FRONT STRETCHING EASTWARD THROUGH SW MN. TEMPERATURES AT 4 AM WERE GENERALLY IN THE MID TO UPPER 40S NORTH AND LOWER TO MIDDLE 50S SOUTH. STRONG WINDS CONTINUED NEAR LAKE SUPERIOR...WITH KDYT AND KDLH STILL GUSTING ABOVE 40 MPH. THE RAIN HAD DIMINISHED CONSIDERABLY ACROSS THE SOUTHERN THIRD OF THE CWA BUT CONTINUED FROM THE TWIN PORTS NORTHWARD. THE MAIN FOCUS FOR TODAY THROUGH SUNDAY IS THE EXTENT AND TIMING OF VARIOUS WAVES OF PRECIPITATION. THE NAM AND THE NSSL AND NCEP WRF RUNS SEEM TO HAVE A DECENT HANDLE ON THE SITUATION. THEY ALL BRING A REPRIEVE IN THE RAIN TO THE SOUTHERN CWA...BEFORE INCREASING AGAIN THIS AFTERNOON. DESPITE SOME BREAKS IN THE PRECIPITATION...THERE SHOULD BE AREAS OF DRIZZLE AS WELL. WILL CONTINUE WITH HIGH POPS. A LITTLE CONCERNED WE MAY NEED TO EVENTUALLY PULL BACK ON POPS IN THE SOUTH...BUT KEPT THEM HIGH DUE TO THE POTENTIAL FOR DRIZZLE. RAIN SHOULD BECOME WIDESPREAD AGAIN TONIGHT...AS SURFACE LOW PRESSURE RE-FORMS OVER WISCONSIN. FOR THAT REASON...WILL CONTINUE WITH HIGH POPS TONIGHT...AND THEN GRADUALLY DECREASE IN PLACE AS THE LOW STARTS TO FALL APART ON SUNDAY. WILL CONTINUE POPS THROUGHOUT THE DAY THOUGH...AS THERE SHOULD BE SOME LINGERING PRECIPITATION. WILL CONTINUE WITH THE WIND ADVISORY FOR TODAY DUE TO THE STRONG EASTERLY WINDS COMING OFF LAKE SUPERIOR. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 ANOMALOUS SFC/MID LVL LOW WILL DRIFT EAST OF REGION BE EARLY MONDAY AS SPLIT FLOW IN WESTERLIES ALLOWS NRN BRANCH TO DEEPEN OVER REGION. PRECIP WILL GRADUALLY DIMINISH OVER THE ERN CWA AS CYCLONIC CIRCULATION LOOSENS ITS GRIP MONDAY. MDLS AGREE THAT A RELATIVELY QUIET DRY WEATHER PATTERN WILL COMMENCE TUESDAY AND PERSIST THROUGH THE WEEK. SYNOPTIC PATTERN WILL FEATURE A DEVELOPING LARGE AMPLITUDE UPPER TROF OVER CALIFORNIA WITH A BROAD UPPER RIDGE ACROSS THE NRN PLAINS AND THE WRN GT LAKES. A SFC TROUGH WILL BEGIN TO FORM OVER THE PLAINS AND EXTEND NORTH INTO NWRN MN BY WED EVENING. ALTHOUGH A WARM ADVECTION REGIME WILL BECOME MORE PRONOUNCED ACROSS THE CWA AT THIS TIME IT APPEARS THE MORE FAVORABLE LIFT WILL OCCUR TO THE WEST OF THE REGION THROUGH THURSDAY. CONFIDENCE LOWERS BY FRIDAY AS TO HOW FAR EAST THE EJECTING MID LVL SYSTEM WILL TRACK DUE TO DOWNSTREAM UPPER RIDGE OVER MS RIVER VALLEY. WILL KEEP MAINLY DRY OVER ALL OF CWA THROUGH FRIDAY BEFORE ALLOWING POPS TO RENTER THE CWA FRIDAY NIGHT. TEMPS WILL RISE ABOVE CLIMO MOST OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1232 PM CDT SAT OCT 5 2013 IFR AND MVFR CIGS/VSBYS WILL PERSIST THROUGH TODAY AND MOST OF TONIGHT BEFORE GRADUAL IMPROVEMENT IS SEEN BY LATE SUNDAY MORNING ACROSS THE WRN TERMINALS. LIGHT SCATTERED RAIN SHOWERS ARE EXPECTED THIS AFTERNOON WITH MORE WIDESPREAD HEAVIER SHOWERS POSSIBLE THIS EVENING...AFTER 23/00Z...LASTING THROUGH 05/06Z. VSBYS WILL LOWER IN THE STRONGER SHOWERS...WITH POSSIBLY PATCHY FOG AROUND DLH AND HYR TONIGHT. GUSTY NE WINDS WILL SLOWLY DIMINISH IN INTENSITY AND BACK TO THE NORTH TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 47 51 41 / 80 80 60 20 INL 47 39 54 38 / 70 50 40 10 BRD 54 46 53 40 / 80 80 60 20 HYR 57 44 59 41 / 80 80 50 30 ASX 55 49 57 44 / 80 80 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ020-037. WI...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR WIZ001-002. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LSZ121-140-148. && $$ SHORT TERM...DAP LONG TERM...CANNON AVIATION...BJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1048 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1034 AM CDT SAT OCT 5 2013 A TRICKY FORECAST TO SAY THE LEAST FOR TODAY. DRY SLOT HAS MOVED IN BEHIND THE OCCLUDED FRONT THIS MORNING...WITH PARTIAL CLEARING OF SKIES SEEN WEST AND SOUTH OF THE TWIN CITIES. AFTER MAKING GOOD PROGRESS OVERNIGHT...THIS CLEARING HAS PUT ON THE BREAKS AS THE LOW OVER SE SODAK HAS STARTED TO DRIFT ESE. THIS WILL KEEP THE CLEARING FROM MAKING IT MUCH FARTHER NORTH...BUT IT WILL CONTINUE TO SLOWLY CRAWL TOWARD THE EAST TODAY. OF COURSE AS THIS IS GOING ON THE BIGGEST CHANGE TO THE FORECAST IS THE ADDITION OF SHOWERS THIS AFTERNOON FROM MANKATO TO ST. CLOUD ON EAST. THE HRRR HAS BEEN SHOWING THIS AREA OF SHOWERS DEVELOPING BACK TO THE WEST FOR SEVERAL RUNS NOW. LOOKING AT THE RAP...THIS IS IN RESPONSE TO A STRONG BAND OF FGEN COMING UP FROM IOWA IN THE H7-H5 LAYER. LOOKING DOWN TO THE SOUTHWEST ON SATELLITE...YOU CAN SEE THIS AREA OF PRECIP STARTING TO TAKE SHAPE FROM ERN KANSAS UP INTO WRN IOWA. BOOSTED POPS UP TO AROUND 50 PERCENT BACK TO THE CITIES THIS AFTERNOON...BUT IF THE HRRR IS CORRECT...MAY NEED TO BOOST THEM UP SIGNIFICANTLY IN THE NEAR FUTURE...ESPECIALLY CONSIDERING ALL 4 MEMBERS OF THE 05.09 HOPWRF SHOW SOMETHING SIMILAR HAPPENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE POTENCY OF THIS EARLY FALL SYSTEM WAS AGAIN ON DISPLAY LAST NIGHT WITH STRONG TO SEVERE STORMS IN THE WARM SECTOR AND A RAGING BLIZZARD IN WESTERN SOUTH DAKOTA. FURTHERMORE...THE SYSTEM HAS BEEN OCCLUDED FOR 12-18 HOURS NOW AND WE STILL SAW A 1-2 MB MSLP PRESSURE DROP OVERNIGHT. THE TROWAL IS CREATING A HOME RUN HITTING DEFORMATION BAND FROM NORTHERN MN TO ND TO SD. IN FACT...THE PRECIP SHIELD ALONG THE COLD CONVEYOR BELT ACTUALLY EXTENDS ALL THE WAY FROM WYOMING TO MICHIGAN...AND THUNDERSTORMS ALONG THE COLD FRONT EXTEND FROM MICHIGAN TO TEXAS. NOT A SMALL SYSTEM BY ANY MEANS. THE FORECAST AREA WILL FIND ITSELF IN THE DRY SLOT MOST OF THE DAY TODAY AND ALSO TONIGHT TO SOME DEGREE. HOWEVER SOME DRIZZLE IS POSSIBLE AND THE CLOUDS SHOULD LARGELY STAY IN TACT. THE OCCLUDED BOUNDARY ISN`T GOING ANYWHERE...ESPECIALLY FOR CENTRAL MN/WI. SOUTHERN PORTIONS OF THE FORECAST AREA /THAT`S RIGHT...SOUTHERN/ ARE CLOSER TO THE COLDER AND DRIER AIR...SO THERE IS A BETTER CHANCE OF AT LEAST PARTIAL CLEARING TODAY IN SOUTHERN MN. MUCH COLDER AIR ALOFT ARRIVES TONIGHT...SO THE STRATUS WON`T BE FAR BEHIND EVEN IF THERE IS CLEARING DURING THE DAY TODAY. THE 00-06Z GUIDANCE IS TOO FAR SOUTH WITH THE DEFORMATION PRECIP BAND THIS MORNING...AS THE FORECAST AREA IS VIRTUALLY PRECIP FREE. IT`S ALSO NOT DEEP ENOUGH WITH THE SURFACE LOW. TRIED TO KEEP THE POPS TODAY ON THE OUTER EDGES OF THE FORECAST AREA TO COUNTER THIS AND ALSO TO STAY CLOSE TO SURROUND FORECAST OFFICES. OTHERWISE...WINDS WILL FALL OFF AS THE LOW SLOWLY FILLS AND MOVES OVERHEAD. IF THE CLOUDS CLEAR ANYWHERE TONIGHT...FOG COULD BE A PROBLEM...TOOK THE SIDE OF LOW STRATUS FOR NOW. NEAR STEADY TEMPERATURE TODAY SO MADE LITTLE ADJUSTMENT TO THE PREVIOUS FORECAST. WE ADJUSTED DEWPOINTS BY KEEPING SLIGHTLY HIGHER VALUES NEAR THE FRONT AND COOLER VALUES CLOSER TO THE DRY SLOT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE SFC LOW FROM THE POTENT/DEEP SYSTEM AFFECTING THE REGION WILL SHIFT INTO WI BY DAYBREAK SUN MRNG WHILE THE LOW PRES CENTER ALOFT WILL SHIFT SE INTO NRN IA. AS THESE TWO LOWS MOVE EAST IN TANDEM SLOWLY DURG THE DAY ON SUN...THE DRY SLOT OVER MUCH OF THE AREA WILL FILL BACK IN WITH DEEPER MOISTURE WRAPPING AROUND THE UPPER LEVEL LOW. COLD ALOFT COMBINED WITH LOW LEVEL WINDS SHIFTING TO A MORE NLY DIRECTION WILL AID IN KEEPING LOW CLOUDS IN PLACE FOR MUCH OF THE DAY...ALONG WITH A DRIZZLE/RAIN SCENARIO FOR SENSIBLE WX. THE UPPER LOW WILL SHIFT ESE INTO CENTRAL IL BY MON MRNG...DRAGGING MUCH OF THE MOISTURE WITH IT BUT THERE WILL STILL BE A CHC FOR LINGERING SHOWERS IN WRN WI ON MON WHILE SRN/CENTRAL MN STARTS TO CLEAR OUT. CONDS WILL GRADUALLY IMPROVE DURG THE DAY ON MON AS HIGH PRES FROM SW CANADA DROPS IN. DESPITE THE COOL ORIGIN OF THIS AIRMASS...IT WILL BE QUICKLY MODIFIED BY AN UPPER LEVEL RIDGE THAT WITH INCRG H5 HEIGHTS WILL SPELL A WARMING TREND ALONG WITH A PROLONGED DRYING-OUT PERIOD FOR THE AREA. DRY WX IS FORECAST MON THRU THU WITH HIGHS RISING BACK INTO THE MID 70S. MODELS CONTINUE TO ADVERTISE ANOTHER POTENT SYNOPTIC-SCALE LOW PRES SYSTEM TO DEVELOP IN THE LEE OF THE ROCKIES THU NIGHT INTO FRI MORNING...WITH IT QUICKLY MOVG NEWD INTO THE DAKOTAS FRI. THIS MAY ALLOW FOR SOME MID-TO-LATE DAY SHWRS/TSTMS OVER WRN MN ON FRI AS THIS SYSTEM ADVANCES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 623 AM CDT SAT OCT 5 2013 CONDITIONS HAVE GENERALLY BEEN IFR WITH LIFR AT TIMES AND MVFR AT OTHERS. WE EXPECTED LITTLE CHANGE FOR THE NEXT 2-4 AT THE TAF SITES AS THE DRIER AIR TAKES ITS TIME TO ARRIVE. HOWEVER...WE DO EXPECT IMPROVEMENT BY THE LATE MORING OR EARLY AFTERNOON. ITS HARD TO IMAGINE SKIES GOING MOSTLY SUNNY FOR TOO LONG...AS CU WITH MVFR CEILINGS SHOULD FILL IN...BUT WE THINK KMSP/KEAU/KRNH/KSTC ALL HAVE A CHANCE FOR MVFR OR EVEN VFR THIS AFTERNOON. LITTLE RAIN IS EXPECTED TODAY AND EVEN TONIGHT - LIGHT RAIN THIS MORNING OR DRIZZLE AS LONG AS THERE ARE LOW CLOUDS AROUND. KMSP... LOW CEILINGS WILL CONTINUE FOR WHAT REMAINS OF THE EARLY MORNING...BUT WE HAVE HIGH CONFIDENCE IN IMPROVEMENT BY THE EARLY AFTERNOON. ANY CLEARING LATER TODAY SHOULD BE RELATIVELY SHORT LIVED WITH WRAP AROUND CLOUD COVER MOVING BACK IN LATE THIS EVENING. ONLY A LITTLE BIT OF LIGHT RAIN OR DRIZZLE TODAY AND THAT SHOULD PRIMARILY BE CONFINED TO THE MORNING. THE STEADIER LIGHT RAIN RETURNS TOMORROW. /OUTLOOK FOR KMSP/ SUN...MVFR OR IFR LIKELY. PERIODS OF -RA/-DZ. WINDS NW 10-15 KTS. MON...VFR...MVFR POSSIBLE EARLY. WINDS W 5-10 KT. TUE...VFR. WINDS S 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...MPG SHORT TERM...CLF LONG TERM...JPC AVIATION...CLF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1030 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1029 AM CDT SAT OCT 5 2013 THE SURFACE LOW WAS LOCATED IN SOUTHEAST SOUTH DAKOTA AS OF 15Z WITH AN OCCLUDED FRONT EXTENDING FROM THIS LOW ACROSS PORTIONS OF S-C MINNESOTA INTO FAR SOUTHWEST WISCONSIN. 925MB BOUNDARY IS IN NEARLY THE SAME LOCATION WITH HIGHER THETA-E AIR NORTH AND EAST OF THE BOUNDARY. THIS FRONT MARKED A CLEARING LINE WITH DRY CONDITIONS BEHIND IT OVER MUCH OF SOUTHERN MINNESOTA. LIGHT RAIN/DRIZZLE CONTINUED OVER PORTIONS OF THE NORTHLAND THIS MORNING...BUT WASN`T REAL WIDESPREAD. WE TRIMMED BACK SOME ON POPS THROUGH MID AFTERNOON BUT MAY HAVE TO FURTHER AS SEVERAL OBSERVATIONS WERE NOT REPORTING ANY RAIN AS OF 15Z. WE DO EXPECT AN INCREASE IN COVERAGE LATER THIS AFTERNOON AS THE STACKED LOW PRESSURE SYSTEM MOVES FURTHER EAST. THE LATEST HRRR WAS DOING A DECENT JOB DEPICTING THE LIGHT RAIN THIS MORNING AND SHOWS COVERAGE INCREASING QUITE A BIT MID TO LATE AFTERNOON ACROSS THE SOUTHERN THIRD...THEN FURTHER NORTH THIS EVENING. THE 12Z NAM SUPPORTS THE HRRR BUT STILL MAY BE OVERDONE WITH IT`S QPF. AREAS OF DRIZZLE WILL ALSO OCCUR AROUND LAKE SUPERIOR. WE CONTINUE TO MONITOR RADAR TRENDS AND LATEST MODEL OUTPUT AND ADJUST AS NEEDED. IT REMAINS WINDY AROUND LAKE SUPERIOR...ESPECIALLY FROM SILVER BAY TO THE TWIN PORTS AND ALONG THE BAYFIELD PENINSULA. KDLH WAS GUSTING TO 42 MPH AS OF THE 1008 AM OBSERVATION AND TO 46 MPH ON PARK POINT. WE`LL KEEP THE WIND ADVISORY GOING AS IS FOR NOW. WE MAY NEED TO EXTEND IT FOR THE TWIN PORTS AREA TO TWO HARBORS/SILVER BAY. THE WIND WASN`T AS STRONG ACROSS BAYFIELD/ASHLAND COUNTIES BUT SOME HIGHER GUSTS WILL REMAIN POSSIBLE THERE AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 AT 4 AM...RAIN CONTINUED TO MOVE NORTHWARD ACROSS THE CWA. THE MASSIVE LOW PRESSURE SYSTEM WAS LOCATED IN CENTRAL SOUTH DAKOTA...WITH AN OCCLUDED FRONT STRETCHING EASTWARD THROUGH SW MN. TEMPERATURES AT 4 AM WERE GENERALLY IN THE MID TO UPPER 40S NORTH AND LOWER TO MIDDLE 50S SOUTH. STRONG WINDS CONTINUED NEAR LAKE SUPERIOR...WITH KDYT AND KDLH STILL GUSTING ABOVE 40 MPH. THE RAIN HAD DIMINISHED CONSIDERABLY ACROSS THE SOUTHERN THIRD OF THE CWA BUT CONTINUED FROM THE TWIN PORTS NORTHWARD. THE MAIN FOCUS FOR TODAY THROUGH SUNDAY IS THE EXTENT AND TIMING OF VARIOUS WAVES OF PRECIPITATION. THE NAM AND THE NSSL AND NCEP WRF RUNS SEEM TO HAVE A DECENT HANDLE ON THE SITUATION. THEY ALL BRING A REPRIEVE IN THE RAIN TO THE SOUTHERN CWA...BEFORE INCREASING AGAIN THIS AFTERNOON. DESPITE SOME BREAKS IN THE PRECIPITATION...THERE SHOULD BE AREAS OF DRIZZLE AS WELL. WILL CONTINUE WITH HIGH POPS. A LITTLE CONCERNED WE MAY NEED TO EVENTUALLY PULL BACK ON POPS IN THE SOUTH...BUT KEPT THEM HIGH DUE TO THE POTENTIAL FOR DRIZZLE. RAIN SHOULD BECOME WIDESPREAD AGAIN TONIGHT...AS SURFACE LOW PRESSURE RE-FORMS OVER WISCONSIN. FOR THAT REASON...WILL CONTINUE WITH HIGH POPS TONIGHT...AND THEN GRADUALLY DECREASE IN PLACE AS THE LOW STARTS TO FALL APART ON SUNDAY. WILL CONTINUE POPS THROUGHOUT THE DAY THOUGH...AS THERE SHOULD BE SOME LINGERING PRECIPITATION. WILL CONTINUE WITH THE WIND ADVISORY FOR TODAY DUE TO THE STRONG EASTERLY WINDS COMING OFF LAKE SUPERIOR. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 ANOMALOUS SFC/MID LVL LOW WILL DRIFT EAST OF REGION BE EARLY MONDAY AS SPLIT FLOW IN WESTERLIES ALLOWS NRN BRANCH TO DEEPEN OVER REGION. PRECIP WILL GRADUALLY DIMINISH OVER THE ERN CWA AS CYCLONIC CIRCULATION LOOSENS ITS GRIP MONDAY. MDLS AGREE THAT A RELATIVELY QUIET DRY WEATHER PATTERN WILL COMMENCE TUESDAY AND PERSIST THROUGH THE WEEK. SYNOPTIC PATTERN WILL FEATURE A DEVELOPING LARGE AMPLITUDE UPPER TROF OVER CALIFORNIA WITH A BROAD UPPER RIDGE ACROSS THE NRN PLAINS AND THE WRN GT LAKES. A SFC TROUGH WILL BEGIN TO FORM OVER THE PLAINS AND EXTEND NORTH INTO NWRN MN BY WED EVENING. ALTHOUGH A WARM ADVECTION REGIME WILL BECOME MORE PRONOUNCED ACROSS THE CWA AT THIS TIME IT APPEARS THE MORE FAVORABLE LIFT WILL OCCUR TO THE WEST OF THE REGION THROUGH THURSDAY. CONFIDENCE LOWERS BY FRIDAY AS TO HOW FAR EAST THE EJECTING MID LVL SYSTEM WILL TRACK DUE TO DOWNSTREAM UPPER RIDGE OVER MS RIVER VALLEY. WILL KEEP MAINLY DRY OVER ALL OF CWA THROUGH FRIDAY BEFORE ALLOWING POPS TO RENTER THE CWA FRIDAY NIGHT. TEMPS WILL RISE ABOVE CLIMO MOST OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 643 AM CDT SAT OCT 5 2013 INITIAL AREA OF RAIN IS PUSHING NORTH OF MOST TERMINALS WITH REDEVELOPMENT OVER SERN MN. LOW CLOUDS WILL BE EXTENSIVE TODAY AS MID LVL DRY SLOT MOVES OVERHEAD. CONFIDENCE ON REDEVELOPMENT OF RAIN AT MOST TERMINALS IS LOW. SHOULD SEE SOME INCREASE IN CEILINGS TODAY WITH BDRY LYR WARMING BUT LOWERING OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 44 51 41 / 80 80 60 20 INL 47 39 54 38 / 70 50 40 10 BRD 52 44 53 40 / 80 80 60 20 HYR 57 46 59 41 / 80 80 50 30 ASX 53 46 57 44 / 80 80 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ020-037. WI...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR WIZ001-002. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LSZ121-140-148. && $$ UPDATE...MELDE SHORT TERM...DAP LONG TERM...CANNON AVIATION...CANNON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1157 PM CDT Fri Oct 4 2013 .UPDATE: Issued at 950 PM CDT Fri Oct 4 2013 Inherited forecast still looks on track...so made no major changes. Warm advection SHRAS have moved out of SW IL. SHRA/TSTMS along and ahead of the front across ern KS/wrn MO timed to reach the wrn CWA around 9-10Z...if it holds together. Several solutions have moisture convergence along the front weakening significantly overnight across nthrn MO. Going fcst reflects the assumption that precip in one form or another will reach our CWA prior to daybreak. Besides massaging other grids to reflect ongoing trends...existing fcst looks good. 2% && .SHORT TERM: (Through Late Tonight) Issued at 330 PM CDT Fri Oct 4 2013 Diurnal heating of the unseasonably warm and moist air mass has resulted in weak instability across the region this afternoon. However with little impetus, attempts for convective development thus far across far southeast Missouri and southern Illinois have been short-lived. The HRRR continues to indicate potential for spot storms through sunset within the southern CWA so will continue with some slight chance pops until then. Otherwise attention for tonight turns to the strong storm system currently across the Plains region. Anticipating that a squall line will evolve ahead of the attendant cold front from Nebraska into Oklahoma this evening and this will move eastward as the whole system progresses, with a swath of precipitation also developing overnight in the wake of the front in response to frontogenetical forcing and large scale ascent as a short-wave rotates through the base of the progressive upper trof. The main question then is just how far eastward all of this precipitation will get before daybreak Saturday. The consensus of the model guidance is that it may be after 12z before entering the CWA. At this time I didn`t deviate dramatically from the previous forecast with the leading edge just making it into the western CWA, but reduced pops further east. Areas to the east of the main line will still be under the threat of spotty warm advection activity overnight. Glass .LONG TERM: (Saturday through Next Friday) Issued at 300 PM CDT Fri Oct 4 2013 By Saturday morning, surface cold front to be just west of St. Louis metro area. As the occluded surface low, over southeastern SD, associated with it slowly lifts out to the northeast, front to slowly slide through rest of forecast area. Expect activity that initially forms tonight to diminish by mid morning. Then trying to determine when and where activity will refire as atmosphere becomes more unstable by early afternoon is hard to pin down. With front extending from Quincy to just west of St. Louis to near Monett by 18z Saturday, best chances of storms refiring and some severe weather will be over southeast MO and southern IL. This matches well with the day 2 outlook with this area in a slight risk. Another forecast issue will be temperatures on Saturday. Will see a non-diurnal trend as high temps will be reached early in the day then either remain steady or fall during the afternoon hours. Showers and isolated thunderstorms will taper off Saturday evening before coming to an end. However, could see some scattered showers on Sunday, especially during the afternoon hours as wrap around clouds on back side of system moves through with an upper level shortwave. So have added low chance pops over northeast MO/west central IL with silent slight chance pops further south for now as well as increase cloud cover through this period. Lows Saturday night will be in the low 40s to low 50s with highs only rising into the mid 50s to mid 60s on Sunday. Sunday night could be our coldest night depending on how fast the clouds clear out. For now will err on side of caution and keep more clouds over the region with lows in the low to mid 40s. If clouds completely clear out and winds remain light, could see even cooler temps. Beyond that, surface ridge moves off to the east with a slow warming trend through the week. Temperatures to warm back up into the mid to upper 70s by Thursday. Byrd && .AVIATION: (For the 06z TAFs through 06z Saturday Night) Issued at 1125 PM CDT Fri Oct 4 2013 Latest surface analysis shows the cold frontal boundary entering western Missouri. Band of showers and thunderstorms extending north-central Missouri through north-central Oklahoma continues to move northeast. Expect scattered showers and possible thunderstorm to enter Columbia MO area and Quincy IL around 0900 UTC. Scattered showers and a few thunderstorms will enter STL area after 1500 UTC. Cold front expected to move across STL area after 1700 UTC. Post frontal light rain will continue through late afternoon. Specifics for KSTL: Scattered showers and a few thunderstorms will move through STL area after 1500 UTC. Southwest winds of 8 to 10 kts expected during the mid to late morning hours. Brief stronger gusts are possible in the vicinty of thunderstorms. Cold front expected through STL between 1700 and 1800 UTC. Post frontal light rain expected much of the afternoon and ending late afternoon. Westerly wind of 8 to 10 kts expected during the afternoon. RP && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
900 PM MDT Sun Oct 6 2013 .DISCUSSION... Have made minor adjustments to the sky and wind grids and will issue an update this evening. Surface winds have decreased over the plains and have adjusted accordingly. The RUC continues to indicate a tightening of the surface gradient after 07z and HRRR analysis also supports mid level winds strengthening around this time along the Northern Rocky Mountain Front. This gives some corroboration for the high wind warning that goes in effect for this area at 09z. A chinook arch remains in place adjacent to the northern front range and have adjusted sky grids to better define its location. Temperatures look reasonable. Emanuel && .AVIATION... UPDATED 2348Z. Chinook arch remains in place across the Northern Rocky Mountain Front bringing SCT-BKN mid/upper level clouds to KCTB. Just a few clouds over the remaining terminals. Wind gusts have begun to subside across north-central MT this afternoon with generally light and variable winds over southwest MT. Expect this trend to remain intact through the overnight hours. Wind gusts will pick once again late Monday morning...especially over north-central MT. Gusts could exceed 30kts from the southwest. Foltz && .PREV DISCUSSION...Issued 249 PM MDT Sun Oct 6 2013 Today through Tuesday...Upper ridge over the region will gradually progress eastward overnight. Despite models continuing to show completely clear skies over the forecast area tonight, Have opted to learn from failure and keep a mention of partly to mostly cloudy skies for the Rocky Mountain Front where a persistent chinook arch has defied the skills of every supercomputer that forecasts for this area. Breezy conditions will continue overnight as well, with temperatures expected to remain above guidance values much like those seen last night. Mid level winds are also expected to increase overnight as the next upper disturbance approaches the area causing surface pressure to fall east of the divide. Conditions look borderline favorable for high winds along the Northern Rocky Mountain Front late tonight. Winds will likely diminish during the morning hours but will pick up again during the afternoon as a cold front pushes through the state. Have issued a High Wind Warning for just the Northern Rocky Mountain Front from 3 AM Monday through 6 AM Tuesday. Conditions may also approach high wind criteria along the Southern Rocky Mountain Front and at Norris Hill in Madison County but confidence is not high enough to warrant highlights at this time. Behind the previously mentioned frontal system a moist Pacific flow will bring widespread rain and snow showers to the mountains of the Continental Divide from the Canadian border south to about Highway 200. Temperatures and snow levels drop behind the front with showers continuing over the mountains through late Tuesday but heavy snow accumulations are not expected. mpj Tuesday Night through Sunday...Upper level trof that moves through the PacNW area earlier in the week will continue to drop well south into the Great Basin states, with a closed low pressure center developing along the CA/NV border by late Wed. Moisture on the eastern flank of the trof will spread scattered mtn snow/valley rain showers, mainly over the southwest counties, through Thurs evening. Current long-range forecast models are in decent agreement that the low center will remain far enough that our region will only see light precipitation amounts through midday Thurs. As the Great Basin system exits into the Central Rockies, a second trof and associated cold front will drop south from BC/Alberta late Thurs into Fri. GFS and ECMWF models still not in sync on temperatures and precipitation with this second system, as the ECMWF model continues to be slightly colder and wetter through early Fri afternoon. Late Fri through Sat aftn looks cloudy but dry as we`ll between the departing second trof and the next Pacific system that arrives Sat evening with another round of scattered light showers. High temperatures will remain about 8 to 12 degrees below normal each day of the extended period, with low-mid 50s on Wed-Thur and upper 40s for Fri-Sun. Waranauskas && .PRELIMINARY POINT TEMPS/POPS... GTF 48 70 42 53 / 0 0 0 10 CTB 46 67 40 53 / 0 0 10 20 HLN 36 68 39 53 / 0 10 10 20 BZN 30 67 36 54 / 0 0 0 20 WEY 24 56 31 47 / 0 0 0 20 DLN 33 63 33 49 / 0 0 10 20 HVR 40 74 41 60 / 0 0 0 10 LWT 37 71 37 53 / 0 0 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING from 3 AM Monday to 6 AM MDT Tuesday Northern Rocky Mountain Front. && $$ weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1236 PM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1229 PM CDT SAT OCT 5 2013 STRONG LOW PRESSURE SYSTEM SLOWLY MOVING THROUGH THE NORTHERN PLAINS WILL CONTINUE TO IMPACT THE AVIATION FORECAST IN WESTERN AND NORTH CENTRAL NEBRASKA THROUGH SUNDAY MORNING. SNOW SQUALLS WILL MOVE THROUGH KVTN DURING THE AFTERNOON AND BRING VSBYS DOWN TO 2SM OR LESS AT TIMES. SNOW SHOWER ACTIVITY WILL BEGIN TO TAPER OFF THIS EVENING AND OVERNIGHT. NO SNOW SHOWERS ARE ANTICIPATED TO REACH KLBF...HOWEVER CIGS WILL HOVER AT OR JUST ABOVE MVFR LEVELS THROUGH THE AFTERNOON. GUSTY WINDS NORTHWEST WINDS WILL REMAIN THROUGH THE TAF PERIOD. STRONGEST WINDS GUSTING TO 35 TO 40 KTS ARE EXPECTED THIS AFTERNOON AND EARLY EVENING. WINDS WILL BEGIN TO RELAX AFTER 00Z WITH WIND GUSTS OF 20 TO 25 KTS EXPECTED BY SUNDAY MORNING. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ006>010-022>029-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ004-005-094. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...MARTIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
637 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 637 AM CDT SAT OCT 5 2013 STRONG TO PERHAPS HIGH WIND CONDITION TODAY WITH WINDS OPERATING AT 31032G45KT. GIVEN THE STORM MOTION OF JUST 6 KTS INDICATED BY THE RAP MODEL...STRONGER WINDS COULD DEVELOP. IFR/MVFR IN SNOW AND LOW CIGS SHOULD GRADUALLY DRIFT EAST OF HIGHWAY 83 LATE TONIGHT. THIS AREA OF CLOUDS WILL ALSO DRIFT EAST AT 6 KTS. THE AREA AFFECTED WILL BE MOSTLY ALONG AND NORTH OF NEBRASKA HIGHWAY 2. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ008- 022>027-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005. WINTER STORM WARNING UNTIL NOON MDT TODAY FOR NEZ004-094. WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR NEZ006-007-009-010-028-029. && $$ LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
357 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1226 AM CDT SAT OCT 5 2013 WIDESPREAD SNOW IN NORTHWEST NEBRASKA WILL CONTINUE TONIGHT. IN BBW...LIGHT SNOW IS POSSIBLE BUT LITTLE ACCUMULATION IS EXPECTED. FOR LBF...OGA AND IML...THE PROBABILITY OF PRECIPITATION IN EITHER FORM IS LOW. CLEAR SKY IN SOUTHWEST NEBRASKA IS LIKELY TO BECOME OVERCAST AGAIN BY 08Z...BUT THE CEILING IS LIKELY BE ABOVE 3000 FEET AGL. OTHERWISE...WIND WILL CONTINUE TO BE A CONCERN THROUGH AT LEAST SATURDAY AFTERNOON WITH 310-340 AT 24-28G35-38KT IN THE MORNING...INCREASING TO 32-36G40-44KT BY 15Z OR 16Z AS THE STORM SYSTEM MOVES OUT AND A BLAST OF CANADIAN AIR POURS IN BEHIND IT. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ008- 022>027-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005. WINTER STORM WARNING UNTIL NOON MDT TODAY FOR NEZ004-094. WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR NEZ006-007-009-010-028-029. && $$ SYNOPSIS...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1135 PM MDT FRI OCT 4 2013 .AVIATION... 06Z TAF CYCLE VFR CIGS AND VIZ NEXT 24 HRS. WEATHER SYSTEM CORE EJECTING INTO SOUTH DAKOTA WITH BROAD INTENSE CIRCULATION ALOFT PUSHING WESTERLY WINDS ACROSS NEW MEXICO...AND THESE WILL SHIFT RAPIDLY NORTHERLY BY 00Z SAT EVENING. CLOUD COVER AOA BKN/OVC100 ACROSS THE HEART OF NEW MEXICO WILL EJECT RAPIDLY TO THE NORTHEAST THROUGH 15Z SAT MORNING WITH NEXT ROUND OF GUSTS REDEVELOPING FROM 16Z ONWARD ACROSS WESTERN AND CENTRAL PORTIONS OF THE STATE. WIND SPEEDS DROPPING OFF AFTER 03Z SATURDAY EVENING. SHY && .PREV DISCUSSION...315 PM MDT FRI OCT 4 2013... FRONT HAS BEEN HUNG UP JUST NORTH OF THE UNION COUNTY BORDER ALL DAY...ALTHOUGH THE LOW CLOUDS ASSOCIATED WITH IT LAST NIGHT HAVE DISSIPATED OVER SOUTHEAST AND EAST CENTRAL CO. RUC INDICATES THE BOUNDARY TO PLUNGE SWD WITHIN THE NEXT 3 HOURS. IT ALSO INDICATES A LITTLE MORE MOISTURE OVER PARTS OF THE NORTHEAST...AND RESULT HAS BEEN TO UPGRADE SKY COVER TO PARTLY CLOUDY RATHER THAN CLEAR. STILL MODELS NOT SUGGESTING A HUGE UPTICK IN DEW POINTS THERE OVERNIGHT. NORTHERLY WINDS ASSOCIATED WITH THE FRONT AS IT TRACKS THROUGH THE PLAINS TO BE GUSTY BUT NOT QUITE AS STRONG AS INDICATED 24 HOURS AGO. AS FOR FREEZE HIGHLIGHTS...STILL SOME MARGINAL TEMPERATURES FOR PORTIONS OF THE EAST CENTRAL AND RGV AS WELL AS THE SOUTH CENTRAL HIGHLANDS. AND SATURDAY NIGHT TEMPERATURE GUIDANCE IS STILL LEANING TOWARDS SOME WARMING. FORECAST BOUNDARY LAYER WINDS TONIGHT NORTHEAST OVER THE PLAINS BUT FOR SATURDAY NIGHT THE GFS FORECASTS A MORE WLY WIND FLOW IN THE LOWER LEVELS...AS OPPOSED TO THE NAM/S LIGHT AND VRBL TO WEAK NW WINDS. FORECAST SOUNDINGS INDICATE SOME STEEP INVERSIONS OFF THE DECK AT SELECTED POINTS SATURDAY NIGHT BUT OVERALL THE SOUNDINGS EXHIBIT A WARMING TREND. THINK THERE MAY BE SOME POINTS IN SHELTERED AREAS UNAFFECTED BY WIND THAT COULD REACH THE MAGIC 32 OR SLIGHTLY BELOW OUTSIDE OF OUR FORECAST POINTS TONIGHT...SO WENT AHEAD AND UPGRADED REMAINING EAST CENTRAL ZONES IN THE WATCH. ALSO ADDED THE SOUTH CENTRAL HIGHLANDS TO THE WARNING TONIGHT WITH FORECAST LOWS AGAIN HOVERING NEAR THE FREEZING MARK. BASED ON THE ABOVE MODEL DISCUSSION...HAVE HELD OFF ON ISSUING FURTHER FREEZE HIGHLIGHTS FOR SATURDAY NIGHT. WILL WAIT TO SEE WHAT THE GUIDANCE DOES AS WELL AS WHAT MINS TONIGHT DO. WINDS STILL TO TAPER OFF SATURDAY WITH A WARMING TREND SUNDAY THROUGH TUESDAY. MODELS CONTINUE TO FOCUS ON AN UPPER LOW DIGGING INTO THE SW US AROUND THE MID TO LATE WEEK PERIOD NEXT WEEK. WINDS LOOK TO INCREASE TUESDAY AND MORE SO WEDNESDAY WITH TEMPERATURES FALLING THURSDAY/FRIDAY. WE NOW HAVE SOME MEAGER POPS FOR THE NORTH AND WEST DURING THIS PERIOD...BUT MODELS NOT EXACTLY IN AGREEMENT HOW THIS WILL PLAY OUT. .FIRE WEATHER... CURRENT FIRE WEATHER HIGHLIGHTS ARE MARGINAL BUT WILL KEEP THEM RUNNING THROUGH EVENT EXPIRATION. TUCUMCARI IS SHOWING NEAR RED FLAG CONDITIONS WITH GUSTY WINDS AND TEEN HUMIDITY. THE UPPER LOW WHICH IS CURRENTLY OVER THE CENTRAL ROCKIES AND GREAT PLAINS WILL GRADUALLY SHIFT EASTWARD THE REST OF TODAY...TONIGHT INTO SATURDAY. THE SURFACE WIND FLOW WILL GENERALLY RELAX AS A RESULT ALTHOUGH A BACK DOOR COLD FRONT WILL PUSH ACROSS THE EASTERN PLAINS TONIGHT AND INCREASE WINDS FOR A TIME. A CHILLY NIGHT IS IN STORE WITH FREEZING TO NEAR FREEZING TEMPERATURES EXPECTED ACROSS THE MAJORITY OF THE FIRE WEATHER FORECAST AREA. A HARD FREEZE WILL BE FELT ACROSS THE NORTHERN AND WESTERN MOUNTAINS AND INCLUDE SOME LOWLAND SITES AS WELL. HIGH PRESSURE WILL BE IN CONTROL DURING THE WEEKEND. THE SURFACE WIND FLOW WILL BE MUCH MORE RELAXED ALTHOUGH LOOK FOR SOME NORTHERLY BREEZES ACROSS SOME WESTERN AND CENTRAL AREAS SATURDAY AFTERNOON. THE FLOW ALOFT WILL BE MUCH WEAKER SO MAINLY SURFACE DRIVEN. FAIRLY LIGHT WINDS FOR SUNDAY WITH JUST A FEW BREEZES ALONG INTERSTATE 25 BETWEEN LAS VEGAS TO RATON. MIXING HEIGHTS WILL BE ON THE LOWER SIDE THANKS TO POST COLD FRONTAL INVERSION EFFECTS. THUS VENTILATION RATES WILL BE LOWER. VENTILATION WILL BE THE POOREST ON SUNDAY. EXPECTING A STRONG LOW LEVEL RADIATION INVERSION TO DEVELOP SATURDAY NIGHT. THIS WILL BE ACCOMPANIED BY ADDITIONAL FREEZING TEMPERATURES WITHIN BASINS AND VALLEYS. HIGH TEMPERATURES WILL BE WELL BELOW NORMAL SATURDAY AND BE AROUND 5 TO 10 DEGREES BELOW NORMAL SUNDAY AFTERNOON. HUMIDITY VALUES WILL BE NEAR SEASONABLE LEVELS ON SATURDAY BUT LOWER ON SUNDAY WITH LOTS OF MINIMUM VALUES IN THE TEENS. A MID LEVEL DRY INTRUSION PLUS A WARM UP WILL BE THE CATALYST FOR LOWER HUMIDITY VALUES SUNDAY. WEATHER MODELS REMAIN PERSISTENT WITH DEPICTING RIDGING ON MONDAY AND THEN BREAKING DOWN OR SHIFTING EASTWARD ON TUESDAY. TEMPERATURES WOULD CONTINUE TO WARM WHILE THE UPPER FLOW TURNS MORE SOUTHWESTERLY ON TUESDAY. DRY CONDITIONS WOULD CONTINUE. VENTILATION RATES WILL REMAIN ON THE LOWER SIDE MONDAY ALTHOUGH IMPROVE IN A FEW AREAS COMPARED TO SUNDAY/S READINGS. TRANSPORT WINDS WILL INCREASE TUESDAY SO THE VENTILATION WILL IMPROVE SIGNIFICANTLY THEN. NEAR TO ABOVE NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK AND SURFACE HUMIDITY WILL REMAIN ON THE LOWER SIDE. CURRENTLY HAVE SOME LOCALIZED CRITICAL FIRE WEATHER GROWTH CONDITIONS DEPICTED WITHIN OUR GRIDDED FORECAST TUESDAY AFTERNOON ACROSS THE NORTHEAST SO WILL BE MONITORING THAT TREND. THE LATEST LONG RANGE MODELS CONTINUE TO SHOW A BREEZY TO WINDY PATTERN WEDNESDAY THROUGH FRIDAY AS ANOTHER PACIFIC TROUGH CROSSES OVER THE INTERMOUNTAIN WEST. IT STILL APPEARS TO BE A DRY TROUGH PASSAGE FOR THE FORECAST AREA. THUS...CANT RULE OUT SOME CRITICAL FIRE WEATHER AREAS...MOST LIKELY FAVORING THE EAST...WHERE TEMPERATURES WOULD BE ABOVE NORMAL FOR THE LONGEST. COOLING EXPECTED ACROSS THE WEST ON THURSDAY AND SPREAD ACROSS THE ENTIRE AREA ON FRIDAY. THIS AIR MASS APPEARS TO BE LESS CHILLY COMPARED TO THE CURRENT ONE. VENTILATION WOULD BE QUITE HIGH WEDNESDAY AND THURSDAY AND PROBABLY LOWER SOME ON FRIDAY. CONFIDENCE IS AT LEAST MODERATE FOR THIS SCENARIO. 50 && .ABQ WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 9 AM MDT SATURDAY FOR THE FOLLOWING ZONES... NMZ518-519-524-530>534. && $$ 33
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1136 PM EDT SUN OCT 6 2013 .SYNOPSIS... A STRONG COLD FRONT WILL APPROACH FROM THE WEST OVERNIGHT. THIS FRONT WILL BRING A PERIOD OF HEAVY RAIN AND GUSTY WINDS AS IT CROSSES THE AREA MONDAY WITH A SHARP DROP IN TEMPERATURES IN ITS WAKE. A BRIEF PERIOD OF COOL AND CLOUDY WEATHER TUESDAY WILL GIVE WAY TO INCREASING SUNSHINE ALONG WITH TEMPERATURES THAT WILL GRADUALLY WARM ABOVE NORMAL AS HIGH PRESSURE SETTLES IN ACROSS THE LOWER GREAT LAKES FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... A STRONG COLD FRONT IS LOCATED FROM SOUTHERN ONTARIO TO EASTERN OHIO AS OF 1130PM. RADARS SHOW A BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS ALONG THE LEADING EDGE OF THE FRONT. A SOUTHERLY LOW LEVEL JET AHEAD OF THE FRONT IS KEEPING THE WARM TEMPERATURES OBSERVED ACROSS WESTERN AND CENTRAL NEW YORK ALONG WITH GUSTY WINDS ACROSS THE HILLTOPS AND DOWNSLOPE AREAS EAST OF LAKE ERIE AND ACROSS THE NORTH COUNTY WHERE GUSTS HAVE REACHED AROUND 30 MPH. MODELS SHOW THE JET INCREASING TO 50+ KNOTS AT 925MB WHICH COULD BRING SOME GUSTS TO 40 OR 45 MPH BUT LIKELY REMAINING JUST BELOW WIND ADVISORY CRITERIA. LATEST HRRR SURFACE WIND GUSTS NO HIGHER THAN 35 KTS MAINLY OVER THE EASTERN END OF LAKE ONTARIO. THE COLD FRONT WILL BRING HEAVY RAINS AND EMBEDDED THUNDERSTORMS ACROSS WESTERN NEW YORK BEGINNING LATE TONIGHT THEN SHIFTING TOWARD CENTRAL NEW YORK LATE MORNING OR EARLY AFTERNOON. WIDESPREAD AVERAGE RAINFALL AMOUNTS OF AROUND HALF AN INCH EXPECTED WITH HIGHER AMOUNTS POSSIBLE IN CONVECTION. THE ONLY REASON HIGHER AVERAGE AMOUNTS ARE NOT EXPECTED WILL BE BY VIRTUE OF THE SPEED OF THE FRONT CROSSING THE REGION AS THE UPPER LEVEL LOW RAPIDLY LIFTS NORTHEAST INTO EASTERN CANADA. FOLLOWING THE FRONTAL PASSAGE A SHIFT TO STRONG WEST-SOUTHWESTERLY WINDS IS EXPECTED. 850MB WINDS ARE PROGGED TO BE IN THE 40-45KT RANGE...PROBABLY A LITTLE TOO WEAK TO HIT ADVISORY LEVEL CRITERIA...HOWEVER WIDESPREAD GUSTS TO 35-39KT ARE NOT OUT OF THE QUESTION. TEMPERATURES WILL FALL SHARPLY BEHIND THE FRONT INTO THE 50S. THE COOLER AIR COUPLED WITH A REASONABLY WELL ALIGNED SOUTHWESTERLY WIND PROFILE DOWN LAKE ERIE COULD RESULT IN LAKE EFFECT RAIN SHOWERS DEVELOPING THIS AFTERNOON. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... TO START THIS TIME PERIOD THE 12Z DETERMINISTIC MODELS OF THE NAM/GFS/ECMWF/CMC ALL BRING THE COLD FRONT THROUGH THE REGION TO START MONDAY EVENING. WHILE THE HEAVY RAIN ALONG THE FRONT WILL LIKELY BE JUST TO OUR EAST...THERE WILL STILL BE SOME TRAILING SHOWERS AS A SECONDARY TROUGH PASSES THROUGH THE REGION...AND MORE LIKELY SOME LAKE EFFECT RAIN AS TEMPERATURES AT 850 HPA DROP TO AROUND +2 TO +3C OVER THE LAKES. LAKE RAINS WILL BE MOST PREVALENT THROUGH THE EVENING HOURS BEFORE DRIER AIR ENTRAINS...AND A VEERING WIND BEHIND SHIFTS BANDS SOUTHEASTWARD AS THEY DISSIPATE. WINDS WILL STILL BE BRISK BEHIND THE FRONT MONDAY NIGHT WITH STRONGEST WINDS FELT NEAR THE SHORELINES OF THE GREAT LAKES. TUESDAY AND TUESDAY NIGHT LOOK TO BE DRY AS HIGH PRESSURE NEARS THE REGION. WITH MOISTURE DEPLETING BEHIND THIS SECONDARY TROUGH WE SHOULD SEE SKIES BECOME MOSTLY SUNNY BY TUESDAY AFTERNOON. LINGERING MOISTURE MAY START THE DAY WITH SOME CLOUDS BUT WARM AIR ADVECTION AND RISING HEIGHTS SHOULD ALLOW FOR DAYTIME MIXING ERODING ANY LINGERING MORNING CLOUDS. BEHIND THIS COLD FRONT TEMPERATURES TUESDAY EVEN WITH THE SUNSHINE WILL RISE ONLY INTO THE UPPER 50S TO LOWERS 60S...WHICH IS ACTUALLY NORMAL FOR THIS TIME OF YEAR...BUT MAY FEEL CHILLY SINCE THE LAST WEEK OR SO HAS BEEN QUITE WARM. TUESDAY NIGHT SOME VALLEY FOG IS POSSIBLE THROUGH THE RIVER VALLEYS OF THE SOUTHERN TIER AS HIGH PRESSURE CAMPED OVER THE REGION PROVIDES EXCELLENT RADIATIONAL COOLING CONDITIONS. LOWS WILL DROP BACK INTO THE LOWER 40S TO 30S WITH THE STAR LITE SKIES AND SOME AREAS OF FROST ARE POSSIBLE THROUGH THE SOUTHERN TIER...WYOMING...LIVINGSTON AS WELL AS THE EASTERN LAKE ONTARIO REGION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ANOTHER EXTENDED PERIOD OF DRY WEATHER IS EXPECTED THROUGH THIS TIME PERIOD AS A LARGE SCALE TROUGH AND COLD FRONT WILL HAVE SWEPT THE HUMIDITY EASTWARD ALLOWING FOR SURFACE HIGH PRESSURE FROM THE CENTRAL PLAINS TO EXPAND EASTWARD TOWARDS THE EAST COASTLINE. WITHIN THIS AIRMASS OUR TEMPERATURES ALOFT AT 850 HPA WILL CLIMB INTO THE 12 TO 14C RANGE WHICH WILL ALLOW FOR HIGHS TO BE SLIGHTLY ABOVE NORMAL. WHILE A RIDGE ALOFT WILL EXTEND FROM THE TENNESSEE VALLEY NORTHEASTWARD ACROSS THE EASTERN GREAT LAKES REGION...TROUGHINESS ALONG THE EASTERN SEABOARD WILL MAINTAIN UNSETTLED WEATHER. EXACT TIMING AND PLACEMENT OF AN EASTCOAST DISTURBANCE IS STILL UNCERTAIN...THOUGH THERE IS A SMALL POSSIBILITY THAT LATE IN THE EXTENDED PERIOD SOME ATLANTIC MOISTURE MAY BE THROWN WESTWARD ACROSS OUR EASTERN ZONES. FOR NOW WILL JUST KEEP DRY FORECAST...BUT ALLOW FOR SOME CLOUDS ACROSS EASTERN ZONES. A NEARING COLD FRONT FROM THE WEST SHOULD DIMINISH AS IT ENCOUNTERS A RIBBON OF DRY AIR...HIGH PRESSURE SUBSIDENCE THAT WILL BE ANCHORED OVER OUR REGION AND BETWEEN THE WESTERN ATLANTIC DISTURBANCE. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... A 40-50KT LOW LEVEL JET IS CROSSING THE REGION TONIGHT AHEAD OF AN APPROACHING COLD FRONT FOUND JUST TO THE WEST OF NEW YORK. RADAR WIND PROFILES SHOWING THESE SOUTHERLY WINDS 2-3KFT OFF THE SURFACE WHICH CONFIRMS THAT LLWS IS PRESENT ACROSS ALL WESTERN TAFS. THIS LOW LEVEL JET HAS BROUGHT GUSTY WINDS TO KART WITH LESS OF CHANCE OF STRONG WIND SHEAR IS SURFACE WINDS ARE ALREADY GUSTY. THE COLD FRONT WILL CROSS INTO THE NIAGARA FRONTIER CLOSE TO DAYBREAK MONDAY AND RAPIDLY MARCH ACROSS THE REST OF NEW YORK DURING THE DAY MONDAY. THE FRONT WILL BE ACCOMPANIED BY HEAVY RAIN AND POSSIBLY SOME LIGHTNING. VSBYS IN THIS HEAVY RAIN COULD FALL TO IFR AT TIMES ALONG/JUST AHEAD OF THE FRONT WITH CIGS ONLY DOWN TO MVFR. EXPECT A SHARP WIND SHIFT TO THE WEST-SOUTHWEST BEHIND THE FRONT. A PERIOD OF LAKE EFFECT RAIN SHOWERS IS POSSIBLE DOWNSTREAM OF LAKE ERIE ACROSS THE NIAGARA FRONTIER BEHIND THE FRONT. OUTLOOK... MONDAY NIGHT...MVFR. TUESDAY...MVFR IMPROVING TO VFR. WEDNESDAY THROUGH FRIDAY...VFR. SOME PATCHY MORNING IFR VSBYS IN VALLEY FOG. && .MARINE... SOUTHERLY WINDS ARE INCREASING AHEAD OF AN APPROACHING COLD FRONT TONIGHT RESULTING IN INCREASING WINDS/WAVES ON THE EAST END OF LAKE ONTARIO. THE COLD FRONT WILL CROSS THE LAKES FROM EARLY MONDAY MORNING THROUGH THE REST OF THE DAY. HEAVY RAINS AND POSSIBLE LIGHTNING WILL BE FOLLOWED BY SHARPLY INCREASING SOUTHWESTERLIES BEHIND THE FRONT THAT WILL RAPIDLY PUSH WAVES AS HIGH AS 8 FEET ON LAKE ERIE AND 11 FEET ON LAKE ONTARIO MONDAY NIGHT. THESE WINDS WILL ALSO CAUSE CHOPPY CONDITIONS DOWN THE SAINT LAWRENCE RIVER. WHILE WINDS SHOULD REMAIN BELOW GALE FORCE OVER THE LAKES...GUSTS APPROACHING GALE MAY BE POSSIBLE DURING THIS PERIOD. WINDS AND WAVES SHOULD RAPIDLY SUBSIDE ON TUESDAY HOWEVER AS HIGH PRESSURE MOVES OVER THE LOWER GREAT LAKES WITH GENERALLY TRANQUIL CONDITIONS PREVAILING THROUGH THE REMAINDER OF THE WEEK. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM MONDAY TO 8 AM EDT TUESDAY FOR LEZ040-041. SMALL CRAFT ADVISORY FROM 8 AM TO 10 PM EDT MONDAY FOR LEZ020. SMALL CRAFT ADVISORY FROM 2 PM MONDAY TO 11 AM EDT TUESDAY FOR LOZ042-043. SMALL CRAFT ADVISORY UNTIL 3 PM EDT TUESDAY FOR LOZ045. SMALL CRAFT ADVISORY FROM 5 PM MONDAY TO 3 PM EDT TUESDAY FOR LOZ044. SMALL CRAFT ADVISORY FROM 2 PM MONDAY TO 2 AM EDT TUESDAY FOR SLZ022-024. && $$ SYNOPSIS...SMITH NEAR TERM...SMITH SHORT TERM...THOMAS LONG TERM...THOMAS AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
255 PM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... 240 PM EDT UPDATE... A MUCH DRIER WEATHER PATTERN IS EXPECTED IN THE EXTENDED THAN IN THE NEAR TERM. THE UPPR LVL TROUGH THAT WILL BRING SHOWERS AND THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS WILL PUSH OUT OF THE AREA TUESDAY/TUESDAY NIGHT. IN ITS WAKE AN UPPER AND LOWER LVL RIDGE WILL BUILD INTO THE REGION. THERE WILL STILL BE A SLIGHT CHANCE FOR SHOWERS ON TUESDAY/TUESDAY NIGHT FROM LINGERING MOISTURE OF KAREN BUT WILL DIMINISH QUICKLY THEREAFTER. WENT CLOSELY WITH WPC GUIDANCE AND KEPT THE FORECAST DRY AS CHANCES FOR RAIN ARE VERY MINIMAL THROUGH THE EXTENDED. HIGH TEMPS STARTING WED THROUGH SAT WILL BE MUCH COOLER AS WELL... WITH HIGHS REMAINING IN THE MID TO UPPER 60S EVEN THOUGH CLOUD COVERAGE WILL BE FOR THE MOST PART PARTLY CLOUDY. THESE TEMPS WILL BE CLOSER TO THE SEASONABLE NORM BUT ARE STILL ABOVE AVERAGE. COOLER TEMPS ARE AHEAD. & .AVIATION /19Z SATURDAY THROUGH THURSDAY/... 140 PM EDT UPDATE... A VERY CHALLENGING FORECAST IS IN STORE FOR THE NEXT 24 HOURS AS A WARM FRONT LIFTS NORTH FROM THE BORDER OF PA TO NORTHERN NY. CURRENTLY ACROSS THE REGION A VERY DENSE MVFR STRATUS DECKS LIES ACROSS MUCH OF CENTRAL NY. DUE TO HEATING FROM THE SUN...WE DO EXPECT THESE CLOUDS TO LIFT BRIEFLY TO VFR THIS AFTERNOON/EVENING. CONFIDENCE IS NOT HIGH ON THE TIMING OF THE TRANSITION. THERE IS A CHANCE FOR LIGHT RAIN SHOWERS THIS AFTERNOON...BUT WITHOUT STRONG UPPER FORCING DECIDED TO KEEP OUT OF TAFS DUE TO UNCERTAINTY OF LOCATION. THE OVERALL CHANCE FOR RAIN SHOWERS WILL INCREASE AFTER 00Z TONIGHT AS THE DRAPED WARM FRONT MOVES NORTH. THE BEST CHANCES FOR RAIN ARE AT KRME... KITH... AND KSYR. THESE SHOWERS MAY PERSIST WELL INTO THE AFTERNOON ON SUNDAY AND EXPECT THESE SHOWERS TO BE FUEL ALTERNATE CIGS AND VISBYS. OUTLOOK... SUNDAY THROUGH THURSDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM...KAH AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
158 PM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... 140 PM EDT UPDATE... A VERY CHALLENGING FORECAST IS IN STORE FOR THE NEXT 24 HOURS AS A WARM FRONT LIFTS NORTH FROM THE BORDER OF PA TO NORTHERN NY. CURRENTLY ACROSS THE REGION A VERY DENSE MVFR STRATUS DECKS LIES ACROSS MUCH OF CENTRAL NY. DUE TO HEATING FROM THE SUN...WE DO EXPECT THESE CLOUDS TO LIFT BRIEFLY TO VFR THIS AFTERNOON/EVENING. CONFIDENCE IS NOT HIGH ON THE TIMING OF THE TRANSITION. THERE IS A CHANCE FOR LIGHT RAIN SHOWERS THIS AFTERNOON...BUT WITHOUT STRONG UPPER FORCING DECIDED TO KEEP OUT OF TAFS DUE TO UNCERTAINTY OF LOCATION. THE OVERALL CHANCE FOR RAIN SHOWERS WILL INCREASE AFTER 00Z TONIGHT AS THE DRAPED WARM FRONT MOVES NORTH. THE BEST CHANCES FOR RAIN ARE AT KRME... KITH... AND KSYR. THESE SHOWERS MAY PERSIST WELL INTO THE AFTERNOON ON SUNDAY AND EXPECT THESE SHOWERS TO BE FUEL ALTERNATE CIGS AND VISBYS. OUTLOOK... SUNDAY THROUGH THURSDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1155 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... FNTL BNDRY DRAPED OVER THE TWIN TIERS/NRN PA WITH LIFR/IFR TO THE N OF THE FNT. PROFILES SUGGEST THESE CONDITIONS TO CONTINUE THRU THE MID MRNG HRS...WITH ITH/ELM/BGM/SYR/AVP BLO ALT MINS AND BRIEFLY LIKELY BLO AIRPORT MINS THRU 14Z. COULD SEE SCT -SHRA THIS MRNG 14-16Z AT SYR/RME IF ACTIVITY OVER WRN NY HOLDS TOGETHER. XPCT CIGS TO SLOWLY LIFT LATE THIS MRNG/AFTN TO MVFR MOST SITES. CHCS FOR SHRA APPEAR TO BE GREATEST THIS AFTN NEAR THE FNT AND INCLUDED TEMPOS FOR SHRA AT ITH/ELM/BGM/AVP THIS AFTN. POTNL FOR TSRA ACRS SRN SITES WHICH MAY BE ADDED WITH LATER FCST UPDATES. TNGT...MVFR XPCTD TO PREVAIL THRU 06Z...WITH POTNL FOR MVFR/IFR MAINLY AFTER 06Z AS -SHRA MOV BACK IN. WINDS ON THE LGT SIDE AND RATHER VRBL...MAINLY FROM A NORTHERLY DIRECTION ACRS CNTRL NY...BECMG ERLY OR SELY TNGT. OUTLOOK... SATURDAY NIGHT THROUGH WEDNESDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
922 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... FNTL BNDRY DRAPED OVER THE TWIN TIERS/NRN PA WITH LIFR/IFR TO THE N OF THE FNT. PROFILES SUGGEST THESE CONDITIONS TO CONTINUE THRU THE MID MRNG HRS...WITH ITH/ELM/BGM/SYR/AVP BLO ALT MINS AND BRIEFLY LIKELY BLO AIRPORT MINS THRU 14Z. COULD SEE SCT -SHRA THIS MRNG 14-16Z AT SYR/RME IF ACTIVITY OVER WRN NY HOLDS TOGETHER. XPCT CIGS TO SLOWLY LIFT LATE THIS MRNG/AFTN TO MVFR MOST SITES. CHCS FOR SHRA APPEAR TO BE GREATEST THIS AFTN NEAR THE FNT AND INCLUDED TEMPOS FOR SHRA AT ITH/ELM/BGM/AVP THIS AFTN. POTNL FOR TSRA ACRS SRN SITES WHICH MAY BE ADDED WITH LATER FCST UPDATES. TNGT...MVFR XPCTD TO PREVAIL THRU 06Z...WITH POTNL FOR MVFR/IFR MAINLY AFTER 06Z AS -SHRA MOV BACK IN. WINDS ON THE LGT SIDE AND RATHER VRBL...MAINLY FROM A NORTHERLY DIRECTION ACRS CNTRL NY...BECMG ERLY OR SELY TNGT. OUTLOOK... SATURDAY NIGHT THROUGH WEDNESDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1151 PM EDT SUN OCT 6 2013 .SYNOPSIS... A FEW SHOWERS WILL CONTINUE THIS AFTERNOON AND TONIGHT. A STRONG COLD FRONT WILL CROSS THE CAROLINAS LATE MONDAY...BRINGING A PERIOD OF SHOWERS AND THUNDERSTORMS. MOISTURE AND BLUSTERY CONDITIONS WILL CONTINUE TUESDAY AND WEDNESDAY. A DRYING TREND SHOULD DEVELOP LATER IN THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1100 PM SUNDAY...STREAMER TYPE CONVECTION FROM OFF THE ATL WATERS TO CONTINUE OVERNIGHT. SPEED CONVERGENCE IN THE LOWER LEVELS AS A RESULT OF THE SE-S ONSHORE FLOW CONTINUES TO FIRE LOW TOPPED CONVECTION ACROSS THE ILM COASTAL WATERS AND ONSHORE. WITH THE DAYS INSOLATION OVERWITH...THE ACTIVITY THAT MOVES ONSHORE WILL FOR THE MOST PART BE UNABLE TO SUSTAIN ITS INTENSITY LET ALONE ITS INTEGRITY AS IT PROGRESSES FURTHER INLAND. THIS CURRENTLY IS BEING PLAYED OUT AS ONE LOOPS THE KLTX AND SURROUNDING RADARS. ALTHO CURRENT LTG REMAINS LACKING...THE ACTIVITY OVER THE ADJACENT ATL WATERS WILL HAVE INCREASING AND DEEPER INSTABILITY OVERNIGHT AS ACTIVITY PASSES OVER SSTS THAT ARE AROUND 80 DEGREES. WOULD NOT BE SURPRISED FOR THUNDER TO OCCUR...AND POSSIBLY REACH AND PUSH ONSHORE LATER OVERNIGHT. NO PRONOUNCED UPPER S/W TROF OR VORT TO AFFECT THE FA OVERNITE THAT WOULD PROVIDE ADDITIONAL FORCING TO FURTHER PROMOTE THUNDER. THIS IS NOT PROGGED BY THE MODELS TO OCCUR UNTIL DAYTIME MONDAY WHILE APPROACHING FROM THE WEST. HOWEVER...ENOUGH CAPE MANIFESTS ACROSS THE FA TOWARD DAYBREAK MONDAY AS EXHIBITED BY THE LATEST HRRR MODEL RUN...TO AT-LEAST MENTION ISOLATED THUNDER DURING THIS TIME FRAME. OVERALL...POPS ACROSS THE FA OVERNIGHT WILL RANGE BETWEEN 25 TO 50 PERCENT. WIDESPREAD 70+ SFC DEWPTS CURRENTLY ACROSS THE FA. DO NOT SEE MUCH OF A DOWNWARD OR DECREASING TREND OVERNITE WITH SFC DEWPTS. AS A RESULT...LOOKING AT WIDESPREAD 70 TO 75 DEGREE LOWS FOR TONIGHT...WHICH IS NEARLY 15 DEGREES HIGHER THAN CLIMO NORMS FOR THIS TIME OF THE YEAR. MUST BE GLOBAL WARMING AGAIN. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE SHORT TERM CONTINUES TO TREND TO A VERY ACTIVE PERIOD MOSTLY AS A RESULT OF MODEL CONSENSUS ON THE EVENTS FOR TUESDAY. THE 1200 UTC GFS AND NAM ARE IN AGREEMENT ON A MID LEVEL LOW CUTTING OFF IN THE SOUTHEAST TUESDAY WITH BROAD ISENTROPIC LIFT DEVELOPING BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND THE ASSOCIATED SURFACE LOW/TROUGH TO THE SOUTH. IT WILL BE A RATHER WET AND RAW DAY AS GUIDANCE SHOWS HIGH TEMPERATURES REMAINING IN THE 60S WITH WIND SPEEDS FROM THE EAST/NORTHEAST AT 10-15 MPH. THE LACK OF SATURATION IN THE 305K LAYER AND MODEST ISENTROPIC LIFT...WINDS ARE ACTUALLY FAIRLY LIGHT ABOVE THE SURFACE MAY KEEP QPF VALUES MODEST. HOWEVER SUBSEQUENT SHIFTS MAY WANT TO INCREASE POPS ESPECIALLY LATE IN THE PERIOD AS THE COLUMN SHOWS BETTER SATURATION IN THIS LAYER. AS FOR THE EVENTS MONDAY...LITTLE CHANGE WAS WARRANTED WITH THE FORECAST AS THE MODELS ARE STILL IN AGREEMENT ON THE FRONT...CURRENTLY LOCATED IN THE TENNESSEE VALLEY MOVING ACROSS MONDAY EVENING. MAINTAINED THE LIKELY TO CATEGORICAL POPS WITH THE SAME TEMPORAL TRENDS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...WEDNESDAY NO LONGER LOOKING DRY AS PREVIOUSLY THOUGHT. A WEAK SOUTHERN BRANCH SHORTWAVE LIFTS OUT OF THE GULF OF MEXICO EARLY IN THE WEEK AND CROSSES THE CAROLINAS WEDNESDAY. THERE IS STILL COPIOUS/DEEP MOISTURE IN PLACE AS THE THE MONDAY COLD FRONT ONLY SEEMS TO REMOVE THE SURFACE MOISTURE. THE UPPER SYSTEM INDUCES A WAVE ALONG THE BOUNDARY WELL OFFSHORE ON WEDNESDAY BUT ITS LOCATION IS NOT AGREED UPON BY VARIOUS GUIDANCE. INTERESTINGLY THE EC DOESN`T REALLY DEVELOP A WAVE BUT STILL HAS QPF AS THE UPPER SHORTWAVE MOVES ATOP THE WEDGE. WILL INTRODUCE LOW CHC POPS MAINLY ALONG THE COAST. MOST IF NOT ALL OF THE REMAINDER OF THE PERIOD WILL BRING DRY WEATHER AS BUILDING UPPER LEVEL RIDGE AND SOUTHWARD SPRAWLING SURFACE HIGH OCCUPY OUR LONGITUDE. THE GFS CONTINUES TO SHOW THAT OUR WEDNESDAY SHORTWAVE EVENTUALLY BEARS A LOW OFF THE DELMARVA COAST THAT RETROGRADES AND MAY BRING SOME WEEKEND POPS. FOR NOW THIS LOOKS JUST ANOMALOUS ENOUGH TO CAP POPS AT SLIGHT. THE EC ALSO SHOWS SOME ATLANTIC DEVELOPMENT BUT NOT THE RETROGRADING MOTION. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 00Z...CURRENTLY VFR CONDITIONS ARE BEING REPORTED AT ALL TERMS WITH S-SE WINDS AOB 8 KTS. VFR SHOULD PREVAIL EARLY THIS EVENING WITH MID-LEVEL CIGS 8-10KFT AND FEW/SCT LOW CLOUDS 1-2KFT. SOME TEMPO PERIODS OF MVFR/IFR ARE POSSIBLE BEFORE 06Z ALONG THE COAST... BUT ANY RESTRICTIONS SHOULD BE SHORT-LIVED. FCST SOUNDINGS AND GUIDANCE CALL FOR MVFR/IFR CIGS TO DEVELOP LATER TONIGHT...WHICH MAKES SENSE GIVEN THE MOIST LOW-LEVEL ENVIRONMENT. EXPECT MAINLY MVFR CIGS ALONG THE COAST AND MVFR/IFR CIGS INLAND AFTER 06Z THROUGH SUNRISE. THE LOW-LEVEL WINDS WILL BE TOO STRONG TO SUPPORT ANY FOG. AN APPROACHING COLD FRONT WILL BRING SHRA/ISO TSRA TO OUR FORECAST AREA ON MONDAY. FCST SOUNDINGS SHOW PWAT VALUES SURGING TO NEAR 2 INCHES DURING THE DAY. VFR/MVFR CONDITIONS WILL LIKELY PREVAIL FROM LATE MORNING THROUGH THE AFTN HOURS...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. EXPECT SOUTH WINDS AROUND 10 KTS ON MONDAY...WITH GUSTS OF 15-20 KTS POSSIBLE ALONG THE COAST. BY 00Z TUESDAY...THE COLD FRONT SHOULD BE NEARING KLBT/KFLO. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1100 PM SUNDAY...LATEST PIER AND BUOY OBS ACROSS THE AREA WATERS INDICATE WINDS ARE RUNNING CLOSE TO THE CURRENT FORECAST TREND. WILL ONLY MAKE SLIGHT ADJUSTMENTS TO WIND DIRECTIONS...WITH SE-S BEING ADVERTISED INSTEAD OF INDICATING A SSE WIND DIRECTION. LATEST HRRR SFC WIND OUTPUT ACROSS THE ILM WATERS CONTINUES WITH 10-15 KT...INCREASING TO 15-20 KT BY DAYBREAK. THIS ONSHORE FLOW WILL BUILD SIGNIFICANT SEAS RATHER QUICKLY OVERNIGHT...WITH THE MAJORITY OF THE ILM COASTAL WATERS AT 3 TO 5 FT BY DAYBREAK MONDAY. BUILDING WIND DRIVEN WAVES AT 4 TO 6 SECOND PERIODS WILL DOMINATE THE WAVE SPECTRUM OVERNIGHT. THE SMALL ESE 9 TO 11 SECOND PERIOD GROUND SWELL WILL PROVIDE NO AID FOR INCREASING THE SIG. SEAS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE MARINE COMMUNITY WILL SEE RATHER CHANGEABLE CONDITIONS THROUGH THE PERIOD. EXPECT A SOUTHEAST FLOW OF 15-20 KNOTS INITIALLY. THIS FLOW WILL WEAKEN AND VEER TO THE SOUTH THEN SOUTHWEST BY THE END OF THE DAY MONDAY. A FRONT WILL MOVE ACROSS THE WATERS AROUND 0600 UTC TUESDAY WITH A NORTH TO NORTHEASTERLY FLOW DEVELOPING BY 1200 TUESDAY. SPEEDS WILL INCREASE AS WELL TO 15-20 KNOTS BY THIS TIME. THIS PATTERN WILL REMAIN IN PLACE THROUGH THE END OF THE PERIOD. SIGNIFICANT SEAS ARE 3-5 FEET EARLY IN THE PERIOD WITH A DECREASE MONDAY EVENING. SEAS WILL INCREASE ONCE AGAIN TUESDAY ESPECIALLY LATER IN THE DAY TO POSSIBLY SMALL CRAFT CRITERIA. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...LONG DURATION OF NORTHERLY FLOW EXPECTED. HIGH PRESSURE WEDGING IN EAST OF THE APPALACHIANS TO PRODUCE A MODERATE GRADIENT ACROSS THE WATERS. A WAVE OF LOW PRESSURE SHOULD DEVELOP SOMEWHERE ALONG COLD FRONT STALLED WELL OFFSHORE BUT ITS LOCATION IS UNCERTAIN AT THIS POINT. THIS IS EXPECTED TO MODULATE THE STRENGTH OF THE GRADIENT AND HAVE AN IMPACT ON THE STRENGTH OF THE GRADIENT PINCH AND WHETHER OR NOT WELL NEED ANY HEADLINES OR EVEN BORDERLINE AND SHORT-LIVED ADVISORY OUT ALONG FRYING PAN SHOALS. WHEREVER THIS LOW DEVELOPS...IT WILL PULL AWAY TO THE NORTH AND EAST THURSDAY INTO FRIDAY AND THE SURFACE HIGH WILL REMAIN ENTRENCHED ACROSS THE EASTERN U.S. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH SHORT TERM...SHK LONG TERM...MBB AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
905 PM EDT SUN OCT 6 2013 .SYNOPSIS... A FEW SHOWERS WILL CONTINUE THIS AFTERNOON AND TONIGHT. A STRONG COLD FRONT WILL CROSS THE CAROLINAS LATE MONDAY...BRINGING A PERIOD OF SHOWERS AND THUNDERSTORMS. MOISTURE AND BLUSTERY CONDITIONS WILL CONTINUE TUESDAY AND WEDNESDAY. A DRYING TREND SHOULD DEVELOP LATER IN THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 745 PM SUNDAY...SPEED CONVERGENCE IN THE LOWER LEVELS AS A RESULT OF THE SE-S ONSHORE FLOW CONTINUES TO FIRE LOW TOPPED CONVECTION ACROSS THE ILM COASTAL WATERS AND ONSHORE. WITH THE DAYS HEATING IE. FUEL OVER-WITH...THE ACTIVITY THAT MOVES ONSHORE WILL FOR THE MOST PART BE UNABLE TO SUSTAIN ITS INTENSITY LET ALONE CONTINUING TO OCCUR AS IT PROGRESSES FURTHER INLAND BY 1 COUNTY. THIS CURRENTLY IS BEING PLAYED OUT AS ONE LOOPS THE KLTX AND SURROUNDING RADAR DISPLAYS. ALTHO CURRENT LTG CONTINUES TO LACK...THE ACTIVITY OVER THE ADJACENT ATL WATERS WILL HAVE INCREASING AND DEEPER INSTABILITY OVERNIGHT ESPECIALLY WHERE SSTS ARE AROUND 80 DEGREES. WOULD NOT BE SURPRISED FOR THUNDER TO OCCUR...AND POSSIBLY REACH AND PUSH ONSHORE LATE TONIGHT. NO PRONOUNCED S/W TROF OR VORT IN THE MID-LEVELS TO AFFECT THE FA OVERNITE THAT WOULD PROVIDE ADDITIONAL FORCING TO FURTHER PROMOTE THUNDER. THIS IS NOT PROGGED TO OCCUR UNTIL DAYTIME MONDAY...THE SHORT TERM PERIOD. HOWEVER...ENOUGH CAPE...VIA LATEST HRRR MODEL RUNS...TO AT-LEAST MENTION ISOLATED THUNDER DURING THE PRE-DAWN MON HRS. OVERALL...POPS ACROSS THE FA OVERNIGHT WILL RANGE BETWEEN 20 TO 50 PERCENT. WIDESPREAD 70+ SFC DEWPTS CURRENTLY ACROSS THE FA. DO NOT SEE MUCH OF A DOWNWARD OR DECREASE TREND TO OVERNITE SFC DEWPTS. AS A RESULT...HAVE TWEAKED TONIGHTS MINS UPWARDS ACROSS THE FA... WITH SOME LOCALES UP BY NEARLY A CATEGORY. THIS WILL RESULT IN TONIGHTS MIN FORECAST AT NEARLY 15 DEGREES HIGHER THAN THE CLIMO NORMS. PREVIOUS DISCUSSION............................................... AS OF 3 PM SUNDAY...LOW-TOPPED SEMI-TROPICAL SHOWERS WILL CONTINUE TO MOVE ONSHORE AND DEEPER INTO THE EASTERN CAROLINA INTERIOR INTO THE LATE AFTERNOON AND EARLY EVENING...AS MOISTURE CONVERGENCE IN THE LOW-LEVELS CONTINUES TO SPREAD TO THE NW. WITH DIURNAL COOLING INTO THE OVERNIGHT HOURS...BUOYANCY WILL INCREASE OVER THE MILD OCEAN WATERS...PROLONGING THE PROSPECT OF PASSING SHOWERS TONIGHT. KLTX VAD WIND PROFILE CONTINUES TO SHOW A DEEP SOUTHERLY ONSHORE WIND FLOW SUPPLYING A RICH DOSE OF COLUMN MOISTURE THROUGH 600 MB. BECAUSE THE CONVERGENCE INLAND WILL ENDURE INTO EVENING...SUSPECT WE WILL SEE ISOLATED SHOWERS EXTENDING INTO THE NIGHT HOURS ALSO. WIND SPEEDS IN THE 0-6KM LAYER WILL INCREASE OVERNIGHT AS A COLD FRONT APPROACHES FROM THE WEST...BUT MOISTURE DEPTH AND OVERALL MOISTURE PROFILES DO NOT CHANGE A GREAT DEAL...SO THE PLAN IS TO MAINTAIN ISOLATED TO SCATTERED CONVECTION OVERNIGHT. STORM MOTION WILL AS A CONSEQUENCE INCREASE...REMAINING A TRACK FROM SOUTH TO NORTH. THE COASTAL ZONES SHOULD BECOME SLIGHTLY MORE FAVORED LATE TONIGHT AS BUOYANCY OVER THE WATERS GOES INTO A DIURNAL MAXIMUM. MILD MINIMUMS TEMPS INTO EARLY MONDAY IS EXPECTED IN THE BLUSTERY ONSHORE FLOW...AND WILL BE THE MILDEST AND MOST-HUMID EARLY MORNING WE HAVE SEEN IN A WHILE. LOW 70S ALONG THE COAST AND UPPER 60S TO AROUND 70 OVER THE INTERIOR OF OUR FORECAST REGION IS EXPECTED AT DAYBREAK ON MONDAY. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE SHORT TERM CONTINUES TO TREND TO A VERY ACTIVE PERIOD MOSTLY AS A RESULT OF MODEL CONSENSUS ON THE EVENTS FOR TUESDAY. THE 1200 UTC GFS AND NAM ARE IN AGREEMENT ON A MID LEVEL LOW CUTTING OFF IN THE SOUTHEAST TUESDAY WITH BROAD ISENTROPIC LIFT DEVELOPING BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND THE ASSOCIATED SURFACE LOW/TROUGH TO THE SOUTH. IT WILL BE A RATHER WET AND RAW DAY AS GUIDANCE SHOWS HIGH TEMPERATURES REMAINING IN THE 60S WITH WIND SPEEDS FROM THE EAST/NORTHEAST AT 10-15 MPH. THE LACK OF SATURATION IN THE 305K LAYER AND MODEST ISENTROPIC LIFT...WINDS ARE ACTUALLY FAIRLY LIGHT ABOVE THE SURFACE MAY KEEP QPF VALUES MODEST. HOWEVER SUBSEQUENT SHIFTS MAY WANT TO INCREASE POPS ESPECIALLY LATE IN THE PERIOD AS THE COLUMN SHOWS BETTER SATURATION IN THIS LAYER. AS FOR THE EVENTS MONDAY...LITTLE CHANGE WAS WARRANTED WITH THE FORECAST AS THE MODELS ARE STILL IN AGREEMENT ON THE FRONT...CURRENTLY LOCATED IN THE TENNESSEE VALLEY MOVING ACROSS MONDAY EVENING. MAINTAINED THE LIKELY TO CATEGORICAL POPS WITH THE SAME TEMPORAL TRENDS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...WEDNESDAY NO LONGER LOOKING DRY AS PREVIOUSLY THOUGHT. A WEAK SOUTHERN BRANCH SHORTWAVE LIFTS OUT OF THE GULF OF MEXICO EARLY IN THE WEEK AND CROSSES THE CAROLINAS WEDNESDAY. THERE IS STILL COPIOUS/DEEP MOISTURE IN PLACE AS THE THE MONDAY COLD FRONT ONLY SEEMS TO REMOVE THE SURFACE MOISTURE. THE UPPER SYSTEM INDUCES A WAVE ALONG THE BOUNDARY WELL OFFSHORE ON WEDNESDAY BUT ITS LOCATION IS NOT AGREED UPON BY VARIOUS GUIDANCE. INTERESTINGLY THE EC DOESN`T REALLY DEVELOP A WAVE BUT STILL HAS QPF AS THE UPPER SHORTWAVE MOVES ATOP THE WEDGE. WILL INTRODUCE LOW CHC POPS MAINLY ALONG THE COAST. MOST IF NOT ALL OF THE REMAINDER OF THE PERIOD WILL BRING DRY WEATHER AS BUILDING UPPER LEVEL RIDGE AND SOUTHWARD SPRAWLING SURFACE HIGH OCCUPY OUR LONGITUDE. THE GFS CONTINUES TO SHOW THAT OUR WEDNESDAY SHORTWAVE EVENTUALLY BEARS A LOW OFF THE DELMARVA COAST THAT RETROGRADES AND MAY BRING SOME WEEKEND POPS. FOR NOW THIS LOOKS JUST ANOMALOUS ENOUGH TO CAP POPS AT SLIGHT. THE EC ALSO SHOWS SOME ATLANTIC DEVELOPMENT BUT NOT THE RETROGRADING MOTION. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...CURRENTLY VFR CONDITIONS ARE BEING REPORTED AT ALL TERMS WITH S-SE WINDS AOB 8 KTS. VFR SHOULD PREVAIL EARLY THIS EVENING WITH MID-LEVEL CIGS 8-10KFT AND FEW/SCT LOW CLOUDS 1-2KFT. SOME TEMPO PERIODS OF MVFR/IFR ARE POSSIBLE BEFORE 06Z ALONG THE COAST... BUT ANY RESTRICTIONS SHOULD BE SHORT-LIVED. FCST SOUNDINGS AND GUIDANCE CALL FOR MVFR/IFR CIGS TO DEVELOP LATER TONIGHT...WHICH MAKES SENSE GIVEN THE MOIST LOW-LEVEL ENVIRONMENT. EXPECT MAINLY MVFR CIGS ALONG THE COAST AND MVFR/IFR CIGS INLAND AFTER 06Z THROUGH SUNRISE. THE LOW-LEVEL WINDS WILL BE TOO STRONG TO SUPPORT ANY FOG. AN APPROACHING COLD FRONT WILL BRING SHRA/ISO TSRA TO OUR FORECAST AREA ON MONDAY. FCST SOUNDINGS SHOW PWAT VALUES SURGING TO NEAR 2 INCHES DURING THE DAY. VFR/MVFR CONDITIONS WILL LIKELY PREVAIL FROM LATE MORNING THROUGH THE AFTN HOURS...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. EXPECT SOUTH WINDS AROUND 10 KTS ON MONDAY...WITH GUSTS OF 15-20 KTS POSSIBLE ALONG THE COAST. BY 00Z TUESDAY...THE COLD FRONT SHOULD BE NEARING KLBT/KFLO. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 745 PM SUNDAY...LATEST PIER AND BUOY OBS ACROSS THE AREA WATERS INDICATE WINDS ARE RUNNING JUST SLIGHTLY BELOW THE CURRENT FORECAST TREND. HAVE THEREFORE ADJUSTED THE 1ST SEVERAL HRS OF THE WIND FORECAST TO ACCOUNT FOR THESE CURRENT CONDITIONS...AND THEN APPLIED THE LATEST HRRR SFC WIND OUTPUT ACROSS THE ILM WATERS FOR THE REMAINDER OF THE NIGHT. THIS WILL RESULT IN A PROLONGED SE WIND BEFORE BECOMING DUE S BY DAYBREAK MONDAY...WHICH REMAINS QUITE CLOSE TO THE CURRENT CWF. THIS ONSHORE FLOW WILL BUILD SIGNIFICANT SEAS OVERNIGHT...WITH THE MAJORITY OF THE ILM COASTAL WATERS AT 3 TO 5 FT BY DAYBREAK MONDAY. BUILDING WIND DRIVEN WAVES AT 4 TO 6 SECOND PERIODS WILL DEFINITELY DOMINATE THE WAVE SPECTRUM FOR SIGNIFICANT SEAS TONIGHT. THE SMALL ESE 9 TO 11 SECOND PERIOD GROUND SWELL OF THE PREVIOUS DAYS IS BASICALLY NON- EXISTENT AND WILL PROVIDE NO AID FOR INCREASING SIG. SEAS OVERNIGHT. AS MENTIONED B4...DOMINANT PERIODS WILL RUN 5 TO 6 SECONDS. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SUNDAY...SEA CONDITIONS TO GET A LITTLE BUMPY TONIGHT AS ONSHORE WINDS INCREASE IN ADVANCE OF AN APPROACHING COLD FRONT BUT NO ADVISORIES HOWEVER ARE EXPECTED THROUGH DAYBREAK MONDAY. SSE WINDS AROUND 15 KT WILL INCREASE TO 15-20 KT OVERNIGHT...WITH SEA HEIGHTS RESPONDING AND BUILDING TO 4 FEET...POSSIBLY NEARING 5 FT ACROSS OUR OUTER WATERS AND FRYING PAN SHOALS EARLY ON MONDAY. THEREFOR AN EXERCISE CAUTION STATEMENT IS PLANNED BEGINNING 6AM MONDAY. SHOWERS MOVING SOUTH TO NORTH CAN BE EXPECTED THROUGH TONIGHT OVER THE 0-20 NM WATERS...AND A FEW TSTMS WILL BE POSSIBLE ALSO. SEAS WILL FEATURE GROWING SE WAVES OVERNIGHT WITH DOMINANT PERIODS RUNNING NEAR 6 SEC. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE MARINE COMMUNITY WILL SEE RATHER CHANGEABLE CONDITIONS THROUGH THE PERIOD. EXPECT A SOUTHEAST FLOW OF 15-20 KNOTS INITIALLY. THIS FLOW WILL WEAKEN AND VEER TO THE SOUTH THEN SOUTHWEST BY THE END OF THE DAY MONDAY. A FRONT WILL MOVE ACROSS THE WATERS AROUND 0600 UTC TUESDAY WITH A NORTH TO NORTHEASTERLY FLOW DEVELOPING BY 1200 TUESDAY. SPEEDS WILL INCREASE AS WELL TO 15-20 KNOTS BY THIS TIME. THIS PATTERN WILL REMAIN IN PLACE THROUGH THE END OF THE PERIOD. SIGNIFICANT SEAS ARE 3-5 FEET EARLY IN THE PERIOD WITH A DECREASE MONDAY EVENING. SEAS WILL INCREASE ONCE AGAIN TUESDAY ESPECIALLY LATER IN THE DAY TO POSSIBLY SMALL CRAFT CRITERIA. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...LONG DURATION OF NORTHERLY FLOW EXPECTED. HIGH PRESSURE WEDGING IN EAST OF THE APPALACHIANS TO PRODUCE A MODERATE GRADIENT ACROSS THE WATERS. A WAVE OF LOW PRESSURE SHOULD DEVELOP SOMEWHERE ALONG COLD FRONT STALLED WELL OFFSHORE BUT ITS LOCATION IS UNCERTAIN AT THIS POINT. THIS IS EXPECTED TO MODULATE THE STRENGTH OF THE GRADIENT AND HAVE AN IMPACT ON THE STRENGTH OF THE GRADIENT PINCH AND WHETHER OR NOT WELL NEED ANY HEADLINES OR EVEN BORDERLINE AND SHORT-LIVED ADVISORY OUT ALONG FRYING PAN SHOALS. WHEREVER THIS LOW DEVELOPS...IT WILL PULL AWAY TO THE NORTH AND EAST THURSDAY INTO FRIDAY AND THE SURFACE HIGH WILL REMAIN ENTRENCHED ACROSS THE EASTERN U.S. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH/MJC SHORT TERM...SHK LONG TERM...MBB AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST AND OFF SHORE OF THE CAROLINA COAST TONIGHT AND SUNDAY. WEAK LOW PRESSURE...AND MOISTURE STREAMING AWAY FROM KAREN...WILL MOVE NORTHEAST ALONG A COLD FRONT THAT WILL CROSS THE CAROLINAS ON MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM SATURDAY... SURFACE RIDGE REMAINS IN PLACE OVER CENTRAL NORTH CAROLINA...AND THE MORNING UPPER-AIR ANALYSIS SHOWED THE RIDGE AXIS ALOFT JUST TO OUR WEST. MORNING AMDAR SOUNDINGS AS WELL AS THE SOUNDING FROM KGSO NOTED WARMING ALOFT AROUND 600MB OVER THE LAST 24 HOURS... REPRESENTING STRONG CAPPING. THE LATEST RAP SHOWS THE RIDGE ALOFT BUILDING EAST OVERHEAD DURING THE AFTERNOON...WITH GOOD SUBSIDENCE AND LITTLE OR NO MIXED-LAYER CAPE IN THE LOWEST KM. MORNING SOUNDINGS AND THE KRAX VAD WIND PROFILE NOTED A FAIRLY DEEP...BUT LIGHT...NORTHERLY COMPONENT TO THE WIND WHICH SHOULD VEER DURING THE DAY BASED ON THE LATEST RAP AND MOS GUIDANCE. MAIN CHANGES...ALL MINOR...TO THE FORECAST FOR THE AFTERNOON WERE TO MODIFY THE DIRECTION OF THE LIGHT WIND INTO THE MID-AFTERNOON HOURS...AND NOTE JUST A FEW MORE CLOUDS WITH SOME MOSTLY THIN CIRRUS WORKING ITS WAY EAST OF THE RIDGE AXIS ALOFT. 1000-850MB THICKNESSES FROM THE KGSO 12Z SOUNDING COMBINED WITH THE FORECAST MAXIMUM VALUE OF THAT PARAMETER THIS AFTERNOON GIVES MAXES IN LINE WITH THE FORECAST. LOWS TONIGHT WILL BE SIMILAR TO THIS MORNING...IN THE LOWER/MID 60S...COOLEST IN RURAL AND LOW-LYING AREAS. EXPECT AREAS OF FOG AGAIN TONIGHT UNDER A MAINLY CLEAR SKY...LIGHT WIND...AND SURFACE DEW POINTS LATE AT NIGHT 60 TO 65. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 345 AM SATURDAY... AN IMPRESSIVE UPPER LEVEL LOW CENTERED OVER THE UPPER MIDWEST THIS MORNING WILL TRACK INTO THE CENTRAL MS RIVER VALLEY SUN INTO SUN NIGHT...WHILE ADDITIONAL SHORTWAVE ENERGY (OVER THE 4-CORNERS REGION THIS MORNING) DIGS SOUTHEAST THROUGH THE LOWER MIDWEST INTO THE LOWER MS RIVER VALLEY ALONG THE SOUTHERN PERIPHERY OF THE UPPER LOW. ADDITIONALLY...TROPICAL CYCLONE KAREN IS EXPECTED TO TRACK SLOWLY NORTH TOWARD THE GULF COAST ON SUN...MOVING ASHORE SOMEWHERE IN THE DEEP SOUTH SUN NIGHT. IN THE LOWER LEVELS...A COLD FRONT ASSOC/W AN OCCLUDED SFC LOW ATTENDANT THE UPPER LEVEL LOW WILL TRACK EAST INTO THE TN/OH VALLEY ON SUN...APPROACHING THE SOUTHERN APPALACHIANS SUN NIGHT. PER THE 00Z GUIDANCE...SOUTHERLY RETURN FLOW AND LOW-LEVEL WARM ADVECTION WILL NOT SIGNIFICANTLY STRENGTHEN UNTIL SUN NIGHT...AND THE AIRMASS ON SUNDAY IS EXPECTED TO BE VERY SIMILAR TO TODAY WITH A PRONOUNCED MID-LEVEL CAP AND MEAGER DIURNAL DESTABILIZATION (AT BEST). FORCING FOR ASCENT WILL LARGELY BE ABSENT OVER CENTRAL NC...CONFINED TO THE SEABREEZE OVER THE COASTAL CAROLINAS AND SMALL AMPLITUDE DISTURBANCES IN STRENGTHENING SW FLOW ALOFT OVER FAR WESTERN PORTIONS OF THE STATE DURING THE AFT/EVE. AS A RESULT...WILL CONTINUE TO INDICATE A DRY FCST ON SUN. A RAPID INCREASE IN LOW-LEVEL MOISTURE ASSOC/W STRENGTHENING SOUTHERLY FLOW WILL OCCUR SUN NIGHT AND MON MORNING...WITH ASCENT INCREASING IN THE FORM OF LOW-LEVEL WARM ADVECTION AND DPVA ASSOC/W SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. ALL OF THE 00Z GUIDANCE INDICATES MEASURABLE PRECIP IN THE WESTERN PIEDMONT BY 12Z MON...AND THIS SEEMS CONSISTENT WITH THE AFOREMENTIONED DISCUSSION. WILL INDICATE PRECIP CHANCES INCREASING FROM THE WEST AFTER MIDNIGHT...RANGING FROM 60-80% IN THE FAR WESTERN PIEDMONT TO ~20% ALONG THE I-95 CORRIDOR. EAST OF I-95...FORCING FOR ASCENT WILL BE MUCH WEAKER AND PRECIP CHANCES WILL LARGELY BE TIED TO SHOWER ACTIVITY MOVING INLAND FROM THE ATLANTIC IN ASSOC/W ONSHORE FLOW. AS A RESULT...WILL INDICATE A DRY FCST IN THE FAR NE COASTAL PLAIN WITH A SLIGHT CHANCE SOUTH OF HWY 64 IN THE SE COASTAL PLAIN. THICKNESSES WILL BE SLIGHTLY LOWER (PERHAPS 5-10M) THAN TODAY. THIS...ALONG WITH INCREASING CLOUD COVER DURING THE AFTERNOON SHOULD RESULT IN HIGHS A FEW DEGREES COOLER THAN TODAY IN THE MID 80S (84-88F)...COOLEST IN THE WESTERN PIEDMONT. LOWS SUN NIGHT WILL BE TEMPERED BY CLOUD COVER AND A LIGHT SOUTHERLY BREEZE...IN THE UPPER 60S TO NEAR 70F IN THE SOUTH. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 155 PM SATURDAY... THE 18Z VALID TAF FORECAST WILL BASICALLY BE PERSISTENCE...WITH SOME AFTERNOON CU DIMINISHING LEAVING A FEW CIRRUS STREAMING ATOP THE RIDGE AXIS. LIGHT WINDS...MOSTLY LIGHT SOUTH...WITH DEW POINTS IN THE LOWER TO MID 60S LATE TONIGHT SHOULD RESULT IN AREAS OF FOG ONCE AGAIN. THE HIGHEST PROBABILITIES OF FOG CONTINUE TO BE TOWARD KFAY AND KRWI...LESSER TOWARD THE NORTHWEST. THE TAFS NOTE LOCAL MVFR VISIBILITY TOWARD KGSO AND KINT...LOCAL IFR VISIBILITY AT KRDU...AND RELATIVELY LOWER VISIBILITIES AT KFAY AND KRWI LATE TONIGHT INTO EARLY SUNDAY. WITH MIXING SUNDAY MORNING...A MORE NOTICEABLE SOUTHERLY WIND SHOULD DEVELOP WITH SURFACE SPEEDS AVERAGING JUST UNDER 10KT BY THE END OF THE 18Z VALID TAF PERIOD. BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS PERSIST UNTIL JUST AFTER MIDNIGHT SUNDAY NIGHT INTO MONDAY MORNING. MOISTURE STREAMING NORTH INTO THE CAROLINAS FROM THE GULF AHEAD OF A COLD FRONT LIKELY RESULTS IN CONDITIONS BECOMING SUB-VFR WITH AT LEAST NUMEROUS SHOWERS DEVELOPING. SOUTH WINDS SUNDAY NIGHT INCREASE ALOFT TO 30KT BY 2000FT AS THE SURFACE GRADIENT INCREASES AHEAD OF THE FRONT. BY TUESDAY...AVIATION CONDITIONS ARE EXPECTED TO IMPROVE TO PREDOMINANTLY VFR IN NORTHEAST FLOW BEHIND THE FRONT. THESE CONDITIONS CONTINUE THROUGH THURSDAY...WITH ONLY A SMALL PROBABILITY OF LOW CLOUDS IN A LOW-LEVEL NORTHEAST FLOW LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SEC/DJF NEAR TERM...DJF/VINCENT SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST OFFSHORE THE CAROLINA COAST TONIGHT AND SUNDAY. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST SUNDAY NIGHT...THEN TRACK EASTWARD THROUGH THE CAROLINAS ON MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM SATURDAY... SURFACE RIDGE REMAINS IN PLACE OVER CENTRAL NORTH CAROLINA...AND THE MORNING UPPER-AIR ANALYSIS SHOWED THE RIDGE AXIS ALOFT JUST TO OUR WEST. MORNING AMDAR SOUNDINGS AS WELL AS THE SOUNDING FROM KGSO NOTED WARMING ALOFT AROUND 600MB OVER THE LAST 24 HOURS... REPRESENTING STRONG CAPPING. THE LATEST RAP SHOWS THE RIDGE ALOFT BUILDING EAST OVERHEAD DURING THE AFTERNOON...WITH GOOD SUBSIDENCE AND LITTLE OR NO MIXED-LAYER CAPE IN THE LOWEST KM. MORNING SOUNDINGS AND THE KRAX VAD WIND PROFILE NOTED A FAIRLY DEEP...BUT LIGHT...NORTHERLY COMPONENT TO THE WIND WHICH SHOULD VEER DURING THE DAY BASED ON THE LATEST RAP AND MOS GUIDANCE. MAIN CHANGES...ALL MINOR...TO THE FORECAST FOR THE AFTERNOON WERE TO MODIFY THE DIRECTION OF THE LIGHT WIND INTO THE MID-AFTERNOON HOURS...AND NOTE JUST A FEW MORE CLOUDS WITH SOME MOSTLY THIN CIRRUS WORKING ITS WAY EAST OF THE RIDGE AXIS ALOFT. 1000-850MB THICKNESSES FROM THE KGSO 12Z SOUNDING COMBINED WITH THE FORECAST MAXIMUM VALUE OF THAT PARAMETER THIS AFTERNOON GIVES MAXES IN LINE WITH THE FORECAST. LOWS TONIGHT WILL BE SIMILAR TO THIS MORNING...IN THE LOWER/MID 60S...COOLEST IN RURAL AND LOW-LYING AREAS. EXPECT AREAS OF FOG AGAIN TONIGHT UNDER A MAINLY CLEAR SKY...LIGHT WIND...AND SURFACE DEW POINTS LATE AT NIGHT 60 TO 65. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 345 AM SATURDAY... AN IMPRESSIVE UPPER LEVEL LOW CENTERED OVER THE UPPER MIDWEST THIS MORNING WILL TRACK INTO THE CENTRAL MS RIVER VALLEY SUN INTO SUN NIGHT...WHILE ADDITIONAL SHORTWAVE ENERGY (OVER THE 4-CORNERS REGION THIS MORNING) DIGS SOUTHEAST THROUGH THE LOWER MIDWEST INTO THE LOWER MS RIVER VALLEY ALONG THE SOUTHERN PERIPHERY OF THE UPPER LOW. ADDITIONALLY...TROPICAL CYCLONE KAREN IS EXPECTED TO TRACK SLOWLY NORTH TOWARD THE GULF COAST ON SUN...MOVING ASHORE SOMEWHERE IN THE DEEP SOUTH SUN NIGHT. IN THE LOWER LEVELS...A COLD FRONT ASSOC/W AN OCCLUDED SFC LOW ATTENDANT THE UPPER LEVEL LOW WILL TRACK EAST INTO THE TN/OH VALLEY ON SUN...APPROACHING THE SOUTHERN APPALACHIANS SUN NIGHT. PER THE 00Z GUIDANCE...SOUTHERLY RETURN FLOW AND LOW-LEVEL WARM ADVECTION WILL NOT SIGNIFICANTLY STRENGTHEN UNTIL SUN NIGHT...AND THE AIRMASS ON SUNDAY IS EXPECTED TO BE VERY SIMILAR TO TODAY WITH A PRONOUNCED MID-LEVEL CAP AND MEAGER DIURNAL DESTABILIZATION (AT BEST). FORCING FOR ASCENT WILL LARGELY BE ABSENT OVER CENTRAL NC...CONFINED TO THE SEABREEZE OVER THE COASTAL CAROLINAS AND SMALL AMPLITUDE DISTURBANCES IN STRENGTHENING SW FLOW ALOFT OVER FAR WESTERN PORTIONS OF THE STATE DURING THE AFT/EVE. AS A RESULT...WILL CONTINUE TO INDICATE A DRY FCST ON SUN. A RAPID INCREASE IN LOW-LEVEL MOISTURE ASSOC/W STRENGTHENING SOUTHERLY FLOW WILL OCCUR SUN NIGHT AND MON MORNING...WITH ASCENT INCREASING IN THE FORM OF LOW-LEVEL WARM ADVECTION AND DPVA ASSOC/W SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. ALL OF THE 00Z GUIDANCE INDICATES MEASURABLE PRECIP IN THE WESTERN PIEDMONT BY 12Z MON...AND THIS SEEMS CONSISTENT WITH THE AFOREMENTIONED DISCUSSION. WILL INDICATE PRECIP CHANCES INCREASING FROM THE WEST AFTER MIDNIGHT...RANGING FROM 60-80% IN THE FAR WESTERN PIEDMONT TO ~20% ALONG THE I-95 CORRIDOR. EAST OF I-95...FORCING FOR ASCENT WILL BE MUCH WEAKER AND PRECIP CHANCES WILL LARGELY BE TIED TO SHOWER ACTIVITY MOVING INLAND FROM THE ATLANTIC IN ASSOC/W ONSHORE FLOW. AS A RESULT...WILL INDICATE A DRY FCST IN THE FAR NE COASTAL PLAIN WITH A SLIGHT CHANCE SOUTH OF HWY 64 IN THE SE COASTAL PLAIN. THICKNESSES WILL BE SLIGHTLY LOWER (PERHAPS 5-10M) THAN TODAY. THIS...ALONG WITH INCREASING CLOUD COVER DURING THE AFTERNOON SHOULD RESULT IN HIGHS A FEW DEGREES COOLER THAN TODAY IN THE MID 80S (84-88F)...COOLEST IN THE WESTERN PIEDMONT. LOWS SUN NIGHT WILL BE TEMPERED BY CLOUD COVER AND A LIGHT SOUTHERLY BREEZE...IN THE UPPER 60S TO NEAR 70F IN THE SOUTH. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 1000 AM SATURDAY... 24-HR TAF PERIOD: VFR CONDITIONS AND WINDS UNDER 10KT WILL PREVAIL THE REMAINDER OF THE TAF PERIOD. SURFACE WINDS MAY SHOW A NORTHERLY COMPONENT VEERING GRADUALLY SOUTH DURING THE LATE MORNING AND EARLY AFTERNOON. LATE TONIGHT...UNDER A MOSTLY CLEAR SKY...LIGHT SOUTHERLY WIND...AND PERSISTENT LATE-NIGHT SURFACE DEW POINTS FROM 60 TO 65...EXPECT AREAS OF FOG...WITH LOWEST VISIBILITIES TOWARD KFAY AND KRWI. LOOKING AHEAD: ASIDE FROM A POTENTIAL FOR FOG OR SUB-VFR CEILINGS BETWEEN 08-12Z SUNDAY MORNING...VFR CONDS ARE EXPECTED TO PREVAIL DURING THE DAY SUNDAY WITH CEILINGS SOMEWHAT LOWER THAN PREVIOUS DAYS (3500-4500 FT AGL) IN ASSOC/W THE ONSET OF A LIGHT SOUTHERLY RETURN FLOW OVER WESTERN PORTIONS OF THE STATE AS HIGH PRESSURE MOVES OFFSHORE. EXPECT AN INCREASING CHANCE FOR MVFR/IFR CEILINGS AT ALL TERMINALS IN ADVANCE OF A COLD FRONT PROGRESSING SLOWLY EAST TOWARD THE SOUTHERN APPALACHIANS SUNDAY NIGHT...ALONG WITH AN INCREASING CHANCE FOR RAIN AT THE INT/GSO TERMINALS BETWEEN 06-12Z MONDAY MORNING. EXPECT WIDESPREAD SHOWERS/STORMS DURING THE DAY MONDAY AS THE COLD FRONT TRACKS EAST INTO THE CAROLINAS. UNCERTAINTY IN THE FCST INCREASES THEREAFTER...HOWEVER...IT IS POSSIBLE THAT RAIN AND SUB-VFR CONDITIONS MAY PERSIST MONDAY NIGHT INTO TUESDAY. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/VINCENT SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
314 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST OFFSHORE THE CAROLINA COAST TONIGHT AND SUNDAY. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST SUNDAY NIGHT...THEN TRACK EASTWARD THROUGH THE CAROLINAS ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... LITTLE CHANGE TO THE OVERNIGHT FORECAST NEEDED AS HIGH PRESSURE REMAINS PERSISTENT OVER THE CAROLINAS. SKIES HAVE CLEARED AND WINDS. DEWPOINTS HAVE RECOVERED ANOTHER 2 TO 4 DEGREES SINCE 24 HOURS AGO...MAINLY ACROSS THE SOUTH... AND DEWPOINT DEPRESSIONS ARE ALREADY LESS THAN 5 DEGREES AT MANY OBSERVING SITES. RH CROSS SECTIONS FAVOR SOUTHERN AREAS FOR FOG...AND THE RECENT HRRR RUNS SUPPORT THIS. LOWS MOSTLY IN THE 60-63 RANGE. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 255 PM FRIDAY... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE PERSISTS...WITH MID-LEVEL HEIGHTS ACTUALLY RISING FOR A TIME SATURDAY BEFORE BEGINNING TO FALL AGAIN SATURDAY NIGHT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS SUGGEST A COUPLE OF DEGREES OR SO OF WARMING ALOFT AROUND 500MB SATURDAY...WITH SOME 850MB MOISTURE AVAILABLE ONCE AGAIN SUGGESTIVE OF SOME DIURNAL CUMULUS WITH MIXING SATURDAY MORNING INTO THE AFTERNOON. SUBSIDENCE CONTINUES TO DOMINATE...AND K INDICES ACTUALLY FALL SOMEWHAT ON THE GFS DURING THE DAY SATURDAY. ANOTHER DRY DAY ANTICIPATED WITH LIGHT WINDS EARLY INCREASING A TOUCH...UNDER 10KT...AND SHOWING A SOUTHERLY COMPONENT BEFORE AGAIN DIMINISHING TO FAIRLY LIGHT SOUTHERLY SATURDAY NIGHT. 1000-850MB THICKNESSES SUPPORT HIGHS AROUND THE MOS GUIDANCE...MANY UPPER 80S AND A FEW READINGS AT 90. AVAILABLE LOW-LEVEL MOISTURE SUPPORTS A GREATER PROBABILITY OF AREAS OF FOG ACROSS CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE AGAIN CONTINUED THIS IN THE GRIDDED AND WORDED FORECASTS. OVERNIGHT LOWS SATURDAY NIGHT MAINLY LOWER 60S. -DJF SUNDAY...WINDS ALOFT WILL BACK TO SOUTHWESTERLY AS THE MID-UPPER RIDGE AXIS SHIFTS EAST AND OFFSHORE...WHICH WILL PROMOTE A GRADUAL INCREASE IN MID TO ESPECIALLY HIGH LEVEL MOISTURE THROUGHOUT THE DAY SUNDAY. THE COMBINATION OF THE INCREASING CLOUDS AND THE EASTWARD DEPARTURE OF THE RIDGE ALOFT WILL LIKELY RESULT IN TEMPERATURES UP TO A FEW DEGREES COOLER THAN THOSE OF SAT - OR WITHIN A COUPLE OF DEGREES EITHER SIDE OF 85. THE TIGHTENING MSL PRESSURE GRADIENT IN RETURN FLOW WILL ALSO PROMOTE THE DEVELOPMENT OF A SOUTHERLY BREEZE THAT WILL PEAK IN THE 10-15 KT RANGE OVER THE WESTERN PIEDMONT ACCORDING TO MIXED LAYER WINDS DEPICTED BY BUFR FORECAST SOUNDINGS. DESPITE THE INCREASING MAINLY HIGH CLOUDS...PRECIPITATION CHANCES WILL REMAIN RELATIVELY LOW. WILL ACCORDINGLY TRIM INHERITED PRECIPITATION CHANCES AND CONFINE A SLIGHT CHANCE TO ROUGHLY THE SOUTHERN HALF OF THE CWFA...TO ACCOUNT FOR THE PROPAGATION OF SHOWERS THAT FORM OWING TO ONSHORE FLOW/FRICTIONAL CONVERGENCE AND WEAK HEIGHT FALLS ALOFT...IN A WEAKLY INHIBITED AND UNSTABLE ENVIRONMENT ALONG AND INVOF COASTAL AREAS. -MWS && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY... 24-HR TAF PERIOD: FOG IS EXPECTED TO DEVELOP EARLY THIS MORNING IN ASSOCIATION WITH CLEAR SKIES...CALM WINDS...AND A SEASONABLY MOIST AIRMASS. FOG WILL BE MOST LIKELY AT THE FAY/RWI TERMINALS WHERE IFR-VLIFR VISBYS ARE EXPECTED IN THE 08-12Z TIME FRAME...FOLLOWED BY RDU WHERE MVFR/IFR VISBYS WILL BE POSSIBLE BETWEEN 08-12Z...AND FINALLY THE INT/GSO TERMINALS WHERE MVFR VISBYS WILL BE POSSIBLE BETWEEN 09-12Z. FOG WILL LIFT AND SCATTER OUT TO VFR BETWEEN 12-14Z...WITH VFR CONDITIONS AND LIGHT WINDS THE REMAINDER OF THE TAF PERIOD. LOOKING AHEAD: ASIDE FROM A POTENTIAL FOR FOG OR SUB-VFR CEILINGS BETWEEN 08-12Z SUNDAY MORNING...VFR CONDS ARE EXPECTED TO PREVAIL DURING THE DAY SUNDAY WITH CEILINGS SOMEWHAT LOWER THAN PREVIOUS DAYS (3500-4500 FT AGL) IN ASSOC/W A STRENGTHENING SOUTHERLY RETURN FLOW AS HIGH PRESSURE MOVES OFFSHORE. EXPECT AN INCREASING CHANCE FOR MVFR/IFR CEILINGS AT ALL TERMINALS IN ADVANCE OF A COLD FRONT PROGRESSING SLOWLY EAST INTO THE SOUTHERN APPALACHIANS SUNDAY NIGHT...ALONG WITH AN INCREASING CHANCE FOR RAIN AT THE INT/GSO TERMINALS BETWEEN 06-12Z MONDAY MORNING. EXPECT WIDESPREAD SHOWERS/THUNDERSTORMS DURING THE DAY MONDAY AS THE COLD FRONT TRACKS EAST INTO THE CAROLINAS. UNCERTAINTY IN THE FCST INCREASES THEREAFTER... HOWEVER...IT IS POSSIBLE THAT RAIN AND SUB-VFR CONDITIONS PERSIST MONDAY NIGHT INTO TUESDAY. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...SMITH SHORT TERM...DJF/MWS LONG TERM...BADGETT AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO RESIDE OVER THE REGION THROUGH SUNDAY. INCREASING MOISTURE AHEAD OF BOTH A COLD FRONT...AND TROPICAL STORM KAREN...WILL SPREAD INTO THE REGION FOR THE START OF THE NEXT WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... LITTLE CHANGE TO THE OVERNIGHT FORECAST NEEDED AS HIGH PRESSURE REMAINS PERSISTENT OVER THE CAROLINAS. SKIES HAVE CLEARED AND WINDS. DEWPOINTS HAVE RECOVERED ANOTHER 2 TO 4 DEGREES SINCE 24 HOURS AGO...MAINLY ACROSS THE SOUTH... AND DEWPOINT DEPRESSIONS ARE ALREADY LESS THAN 5 DEGREES AT MANY OBSERVING SITES. RH CROSS SECTIONS FAVOR SOUTHERN AREAS FOR FOG...AND THE RECENT HRRR RUNS SUPPORT THIS. LOWS MOSTLY IN THE 60-63 RANGE. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 255 PM FRIDAY... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE PERSISTS...WITH MID-LEVEL HEIGHTS ACTUALLY RISING FOR A TIME SATURDAY BEFORE BEGINNING TO FALL AGAIN SATURDAY NIGHT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS SUGGEST A COUPLE OF DEGREES OR SO OF WARMING ALOFT AROUND 500MB SATURDAY...WITH SOME 850MB MOISTURE AVAILABLE ONCE AGAIN SUGGESTIVE OF SOME DIURNAL CUMULUS WITH MIXING SATURDAY MORNING INTO THE AFTERNOON. SUBSIDENCE CONTINUES TO DOMINATE...AND K INDICES ACTUALLY FALL SOMEWHAT ON THE GFS DURING THE DAY SATURDAY. ANOTHER DRY DAY ANTICIPATED WITH LIGHT WINDS EARLY INCREASING A TOUCH...UNDER 10KT...AND SHOWING A SOUTHERLY COMPONENT BEFORE AGAIN DIMINISHING TO FAIRLY LIGHT SOUTHERLY SATURDAY NIGHT. 1000-850MB THICKNESSES SUPPORT HIGHS AROUND THE MOS GUIDANCE...MANY UPPER 80S AND A FEW READINGS AT 90. AVAILABLE LOW-LEVEL MOISTURE SUPPORTS A GREATER PROBABILITY OF AREAS OF FOG ACROSS CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE AGAIN CONTINUED THIS IN THE GRIDDED AND WORDED FORECASTS. OVERNIGHT LOWS SATURDAY NIGHT MAINLY LOWER 60S. -DJF SUNDAY...WINDS ALOFT WILL BACK TO SOUTHWESTERLY AS THE MID-UPPER RIDGE AXIS SHIFTS EAST AND OFFSHORE...WHICH WILL PROMOTE A GRADUAL INCREASE IN MID TO ESPECIALLY HIGH LEVEL MOISTURE THROUGHOUT THE DAY SUNDAY. THE COMBINATION OF THE INCREASING CLOUDS AND THE EASTWARD DEPARTURE OF THE RIDGE ALOFT WILL LIKELY RESULT IN TEMPERATURES UP TO A FEW DEGREES COOLER THAN THOSE OF SAT - OR WITHIN A COUPLE OF DEGREES EITHER SIDE OF 85. THE TIGHTENING MSL PRESSURE GRADIENT IN RETURN FLOW WILL ALSO PROMOTE THE DEVELOPMENT OF A SOUTHERLY BREEZE THAT WILL PEAK IN THE 10-15 KT RANGE OVER THE WESTERN PIEDMONT ACCORDING TO MIXED LAYER WINDS DEPICTED BY BUFR FORECAST SOUNDINGS. DESPITE THE INCREASING MAINLY HIGH CLOUDS...PRECIPITATION CHANCES WILL REMAIN RELATIVELY LOW. WILL ACCORDINGLY TRIM INHERITED PRECIPITATION CHANCES AND CONFINE A SLIGHT CHANCE TO ROUGHLY THE SOUTHERN HALF OF THE CWFA...TO ACCOUNT FOR THE PROPAGATION OF SHOWERS THAT FORM OWING TO ONSHORE FLOW/FRICTIONAL CONVERGENCE AND WEAK HEIGHT FALLS ALOFT...IN A WEAKLY INHIBITED AND UNSTABLE ENVIRONMENT ALONG AND INVOF COASTAL AREAS. -MWS && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. HOWEVER... THE 00Z/05 OCTOBER OPERATIONAL EC SUGGESTS THE FRONT MAY HANG UP OVER SC/GA WED... WITH THE MID/UPPER TROUGH HANGING BACK OVER THE SE STATES INTO THURS. WE WILL INCORPORATE A LOW PERCENTAGE OF THIS SOLUTION INTO THE FORECAST AT THE CURRENT TIME. THIS WOULD YIELD PARTLY CLOUDY SKIES IN THE EAST AND SOUTH LATE TUE AND WED. LOWS 50-55. HIGHS 70-75. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 745 PM FRIDAY... AREAS OF FOG ARE EXPECTED DEVELOP LATE TONIGHT BETWEEN 06 TO 12Z......WITH THE HIGHEST PROBABILITY AND CORRESPONDINGLY LOWER VISIBILITIES EXPECTED IN THE EAST AT KRWI AND KFAY. BEYOND THE 18Z VALID TAF PERIOD...AREAS OF FOG WILL BE POSSIBLE AGAIN EARLY SUNDAY MORNING...OTHERWISE EXPECT PREDOMINATELY VFR CONDITIONS THROUGH THE WEEKEND. MOISTURE ASSOCIATED WITH REMNANTS OF TS KAREN WILL SPREAD INTO THE AREA LATE SUNDAY NIGHT AND INTO MONDAY. SUB-VFR CONDITIONS WILL BE POSSIBLE AGAIN LATE SUNDAY NIGHT AND MONDAY MORNING WITH WIDESPREAD SHOWERS AND STORMS MONDAY AFTERNOON THROUGH MONDAY NIGHT WITH CORRESPONDING AREAS OF SUB-VFR CONDITIONS. WIDESPREAD VFR CONDITIONS ARE LIKELY TO RETURN BY TUESDAY AFTERNOON AS A COLD FRONT PUSHES EAST AND OFFSHORE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...SMITH SHORT TERM...DJF/MWS LONG TERM...BADGETT AVIATION...CBL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
146 PM EDT SAT OCT 5 2013 .SYNOPSIS... SOUTHWEST FLOW OF WARM...MUGGY AIR CONTINUES INTO SUNDAY. COLD FRONT BRINGS SHOWERS ALONG WITH SOME STORMS LATE SUNDAY INTO MONDAY. UPPER LOW PULLS OUT MIDWEEK...YIELDING TO HIGH PRESSURE LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... A FEW SMALL WAVES EMBEDDED WITHIN THE UPPER RIDGE HAVE SPARKED SOME CONVECTION OVER THE OHIO VALLEY THIS MORNING...BUT THIS IS NOT ABLE TO GET MUCH IN TERMS OF VERTICAL EXTENT. HAD TO DRAG THE POPS A LITTLE FURTHER TO THE SOUTHEAST...BUT LEFT THEM OUT OF CRW. WILL REASSESS WHEN THE NEW MODELS ARE IN. HRRR HAS BEEN VALUABLE THIS MORNING. PREVIOUS DISCUSSION... SUMMER REPRISE CONTINUES. ALTOCU THIS MORNING AIDS IN ERADICATING THE DENSE VALLEY FOG OF EARLY MORNING...OR HOLDS IT IN IF IT SURVIVES DAWN....AND CU THIS AFTERNOON IN VERY WARM AND HUMID SW FLOW AS UPPER RIDGE MOVES E ACROSS AREA. WEAK RIPPLES IN THE UPPER LEVEL SW FLOW ONCE THE RIDGE GOES BY COULD GRAZE NW PORTION OF AREA WITH CONVECTION MIDDAY TODAY INTO THIS EVENING. FLOW GOES MORE SOUTHERLY TONIGHT...SO CONVECTION ASSOCIATED WITH RIPPLES IN FLOW WILL SHIFT N OF THE AREA WHILE THAT ASSOCIATED WITH COLD FRONT TO THE W REMAINS W OF THE AREA THROUGH 12Z SUN. ALTOCU LIMITED TO THE W. BOUNDARY LATER FLOW SHOULD PRECLUDE DENSE VALLEY FOG SAVE FOR THE DEEPER VALLEYS OF EASTERN WV LATE TONIGHT. ROLLED WITH BIAS CORRECTED ADJMET AND BIAS CORRECTED ALL BLEND TOGETHER WITH PREVIOUS FOR HIGHS TODAY WITH ADJMAV BEING TOO HIGH. LOWER TO MID 80S LOWLANDS IS 5-10F BELOW RECORD HIGHS. DID BLEND IN BIAS CORRECTED ADJMAV FOR LOWS TONIGHT...A TICK OR SO HIGHER THAN PREVIOUS ON RIDGE/HILL TOPS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. RATHER WARM AND HUMID DAY ON TAP SUNDAY...AS UPPER LOW ACROSS CENTRAL U.S. DIGS SOUTH AND EAST...CAUSING FLOW TO BACK...AND SLOWING THE PROGRESSION OF THE COLD FRONT AND ASSOCIATED PRECIPITATION INTO THE CWA. STILL EXPECTING SOME DECENT RAINFALL TOTALS...AS LLJ AIDS IN MOISTURE TRANSPORT TO THE REGION...WITH PW VALUES EXPECTED TO RISE TO 1.6 TO 1.7 INCHES. AS WITH PREVIOUS FORECASTER...WILL LEAVE A MENTION OF WATER PROBLEMS OUT OF THE HWO DUE TO RECENT DRY SPELL...AND OVERALL PROGRESSIVE NATURE OF THE SYSTEM. IN ADDITION...AT THIS POINT...SPC HAS ISSUED ONLY A SEE TEXT AREA FOR THE CWA...AS CLOUD COVER...AND OVERALL LACK OF INSTABILITY SHOULD HOPEFULLY LIMIT THE SEVERE POTENTIAL ACROSS THE REGION. STILL...EXPECTING SOME RATHER GUSTY CONDITIONS ASSOCIATED WITH FRONTAL PASSAGE...SET TO TAKE PLACE ON MONDAY...PARTICULARLY ACROSS HIGHER ELEVATIONS. HOWEVER...THIS WILL NEED TO BE MONITORED AS MODELS ARE INDICATING STRONG FORCING WITH THE FRONT. MODELS CONTINUE TO INDICATE THAT REMNANTS OF KAREN WILL REMAIN FAR ENOUGH TO THE EAST OF THE AREA...THAT THE CWA WILL SEE LITTLE TO NO EFFECT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... LOOKING AT UPR RIDGE TO BUILD ACROSS EASTERN CONUS IN THE EXTENDED WITH STALLED SFC FRONT LINGERING ALONG E COAST. SEASONABLE TEMPS DURING THE DAY AND COOL NIGHTS ON TAP. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... CONVECTION EXPECTED OVER THE OHIO VALLEY AGAIN TODAY...WITH ISOLATED CHANCES IN THE MOUNTAINS. ONLY HAVE VCTS IN THE PKB AREA GIVEN THE CURRENT SET OF POP GRIDS IN PLACE...WHERE THESE VALUES ARE THE HIGHEST. A FEW SHOWERS MAY LINGER AROUND HTS AS WELL...BUT THE BULK OF THE ACTIVITY SHOULD REMAIN CLOSER TO ILN/CMH/ZZV. DID NOT GO WITH MUCH FOG TONIGHT AS RH PROGS HAVE DEPTH OF THE MOISTURE EXTENDING THROUGH 550MB...ALLUDING TO CLOUD COVER IN PLACE. EKN MAY GET LIFR LATE TONIGHT WHERE THE CLOUD COVER IS NOT EXPECTED TO BE AS PROMINENT. WITH THE FRONTAL SYSTEM GETTING CLOSER...WILL SEE SURFACE FLOW AROUND 10KTS OUT OF THE SOUTHWEST SUNDAY. AIR FLOW OFF THE SURFACE WILL BE HIGHER WITH THE APPROACH OF THE LOW LEVEL JET. TRI STATE/SOUTHEAST OHIO LOCATIONS COULD SEE 40-50KTS OFF THE SURFACE AT AROUND 5KFT...ALSO OUT OF THE SOUTHWEST. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: MAY NEED VCSH AT HTS THIS AFTERNOON. BRIEF RAIN IS POSSIBLE AT BOTH PKB/HTS. EKN MAY NOT FOG TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SUNDAY... IFR POSSIBLE ALONG COLD FRONT...MOVING W TO E...SUN NT INTO MON...AND IN POST-RAIN FOG/STRATUS TUE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM/26 SHORT TERM...SL LONG TERM...30 AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1038 AM EDT SAT OCT 5 2013 .SYNOPSIS... SOUTHWEST FLOW OF WARM...MUGGY AIR CONTINUES INTO SUNDAY. COLD FRONT BRINGS SHOWERS ALONG WITH SOME STORMS LATE SUNDAY INTO MONDAY. UPPER LOW PULLS OUT MIDWEEK...YIELDING TO HIGH PRESSURE LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... A FEW SMALL WAVES EMBEDDED WITHIN THE UPPER RIDGE HAVE SPARKED SOME CONVECTION OVER THE OHIO VALLEY THIS MORNING...BUT THIS IS NOT ABLE TO GET MUCH IN TERMS OF VERTICAL EXTENT. HAD TO DRAG THE POPS A LITTLE FURTHER TO THE SOUTHEAST...BUT LEFT THEM OUT OF CRW. WILL REASSESS WHEN THE NEW MODELS ARE IN. HRRR HAS BEEN VALUABLE THIS MORNING. PREVIOUS DISCUSSION... SUMMER REPRISE CONTINUES. ALTOCU THIS MORNING AIDS IN ERADICATING THE DENSE VALLEY FOG OF EARLY MORNING...OR HOLDS IT IN IF IT SURVIVES DAWN....AND CU THIS AFTERNOON IN VERY WARM AND HUMID SW FLOW AS UPPER RIDGE MOVES E ACROSS AREA. WEAK RIPPLES IN THE UPPER LEVEL SW FLOW ONCE THE RIDGE GOES BY COULD GRAZE NW PORTION OF AREA WITH CONVECTION MIDDAY TODAY INTO THIS EVENING. FLOW GOES MORE SOUTHERLY TONIGHT...SO CONVECTION ASSOCIATED WITH RIPPLES IN FLOW WILL SHIFT N OF THE AREA WHILE THAT ASSOCIATED WITH COLD FRONT TO THE W REMAINS W OF THE AREA THROUGH 12Z SUN. ALTOCU LIMITED TO THE W. BOUNDARY LATER FLOW SHOULD PRECLUDE DENSE VALLEY FOG SAVE FOR THE DEEPER VALLEYS OF EASTERN WV LATE TONIGHT. ROLLED WITH BIAS CORRECTED ADJMET AND BIAS CORRECTED ALL BLEND TOGETHER WITH PREVIOUS FOR HIGHS TODAY WITH ADJMAV BEING TOO HIGH. LOWER TO MID 80S LOWLANDS IS 5-10F BELOW RECORD HIGHS. DID BLEND IN BIAS CORRECTED ADJMAV FOR LOWS TONIGHT...A TICK OR SO HIGHER THAN PREVIOUS ON RIDGE/HILL TOPS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. RATHER WARM AND HUMID DAY ON TAP SUNDAY...AS UPPER LOW ACROSS CENTRAL U.S. DIGS SOUTH AND EAST...CAUSING FLOW TO BACK...AND SLOWING THE PROGRESSION OF THE COLD FRONT AND ASSOCIATED PRECIPITATION INTO THE CWA. STILL EXPECTING SOME DECENT RAINFALL TOTALS...AS LLJ AIDS IN MOISTURE TRANSPORT TO THE REGION...WITH PW VALUES EXPECTED TO RISE TO 1.6 TO 1.7 INCHES. AS WITH PREVIOUS FORECASTER...WILL LEAVE A MENTION OF WATER PROBLEMS OUT OF THE HWO DUE TO RECENT DRY SPELL...AND OVERALL PROGRESSIVE NATURE OF THE SYSTEM. IN ADDITION...AT THIS POINT...SPC HAS ISSUED ONLY A SEE TEXT AREA FOR THE CWA...AS CLOUD COVER...AND OVERALL LACK OF INSTABILITY SHOULD HOPEFULLY LIMIT THE SEVERE POTENTIAL ACROSS THE REGION. STILL...EXPECTING SOME RATHER GUSTY CONDITIONS ASSOCIATED WITH FRONTAL PASSAGE...SET TO TAKE PLACE ON MONDAY...PARTICULARLY ACROSS HIGHER ELEVATIONS. HOWEVER...THIS WILL NEED TO BE MONITORED AS MODELS ARE INDICATING STRONG FORCING WITH THE FRONT. MODELS CONTINUE TO INDICATE THAT REMNANTS OF KAREN WILL REMAIN FAR ENOUGH TO THE EAST OF THE AREA...THAT THE CWA WILL SEE LITTLE TO NO EFFECT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... LOOKING AT UPR RIDGE TO BUILD ACROSS EASTERN CONUS IN THE EXTENDED WITH STALLED SFC FRONT LINGERING ALONG E COAST. SEASONABLE TEMPS DURING THE DAY AND COOL NIGHTS ON TAP. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... FOG WAS MORE LIMITED EARLY THIS MORNING COMPARED WITH FRI MORNING AND WILL BE EVEN MORE LIMITED SUN MORNING GIVEN ANOTHER DAY OF LOW SHOWER/THUNDERSTORM COVERAGE...AND SOMEWHAT INCREASED BOUNDARY LAYER FLOW. AS FOR THIS MORNING...THE FOG WILL FINISH THINNING OUT 13-14Z. CIRRUS AND ALTOCU MOVING ACROSS THIS MORNING FOLLOWED BY A BUILDING CU FIELD THIS AFTERNOON. SHOWERS AND THUNDERSTORMS COULD AFFECT THE MIDDLE OHIO VALLEY MIDDAY TODAY INTO THIS EVENING. AN ISOLATED SHOWER OR THUNDERSTORM COULD ALSO POP UP OVER THE NORTHERN WV MOUNTAINS THIS AFTERNOON. LIGHT AND VARIABLE SFC FLOW TODAY BECOMES LIGHT S TO SE TONIGHT WHILE LIGHT NW FLOW ALOFT SWITCHES TO LIGHT SW THIS MORNING AND THEN BECOMES LIGHT S TO SW TONIGHT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: LITTLE MORE THEN MINOR VARIATIONS ARE EXPECTED IN THE FCST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z SUNDAY... IFR POSSIBLE ALONG COLD FRONT...MOVING W TO E...SUN NT INTO MON...AND IN POST-RAIN FOG/STRATUS TUE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM/26 SHORT TERM...SL LONG TERM...30 AVIATION...TRM
AREA FORECAST DISCUSSION
NWS TULSA OK
326 PM CDT SAT OCT 5 2013 .DISCUSSION... BAND OF ONGOING CONVECTION IS ALIGNED ALONG THE 850MB FRONT...AND GIVEN THE LATEST RUC PROJECTIONS...THIS BOUNDARY WILL BE ACROSS FAR WESTERN AR INTO EXTREME SE OK BY 00Z AND PUSHING EASTWARD. ANY EVENING PRECIP WILL BE CONFINED TO THIS ZONE BEFORE PUSHING FURTHER EASTWARD AND CLEAR OF THE FORECAST AREA. SKIES WILL CONTINUE TO CLEAR FROM NW TO SE AND ALLOW FOR A COOL SUNDAY MORNING. BREEZY NORTHWEST WINDS WILL DEVELOP SUNDAY WHILE TEMPERATURES REMAIN BELOW SEASONAL NORMALS. WINDS WILL DROP OFF AROUND SUNSET AND ALLOW TEMPS TO FALL QUICKLY. A SEVERAL DAY WARMING TREND COMMENCES MONDAY WITH TEMPS RETURNING TO ABOVE NORMAL READINGS BY MID WEEK. THE WARM AND DRY WEATHER WILL PREVAIL INTO THE WEEKEND WHEN THE NEXT STORM SYSTEM PUSHES INTO THE PLAINS. WILL INTRODUCE LOW PRECIP CHANCES FOR NEXT WEEKEND PENDING THE EVOLUTION OF THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... TUL 46 70 45 75 / 0 0 0 0 FSM 46 71 46 75 / 20 0 0 0 MLC 43 72 43 77 / 10 0 0 0 BVO 40 69 40 75 / 0 10 0 0 FYV 41 65 39 70 / 10 0 0 0 BYV 43 63 44 69 / 30 0 0 0 MKO 42 70 42 75 / 10 0 0 0 MIO 42 66 42 72 / 0 10 0 0 F10 43 71 44 76 / 0 0 0 0 HHW 47 76 44 79 / 30 0 0 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ LONG TERM....07
AREA FORECAST DISCUSSION
NWS TULSA OK
1141 PM CDT FRI OCT 4 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. LEAD EDGE OF SHOWES/THUNDERSTORMS IS CURRENTLY MOVING INTO NE OKLAHOMA...AND WILL IMPACT THE KBVO/KTUL AND KRVS TAF SITES THROUGH ABOUT 09-10Z. THIS ACTIVITY SHOULD APPROACH SE OKLAHOMA AND NW ARKANSAS LATER TONIGHT TOWARD 10-12Z. OVERALL THUNDERSTORM INTENSITY WILL CONTINUE TO DECREASE. EXPECT AREAS OF MVFR CONDITIONS IN THE STRONGER STORMS. && .PREV DISCUSSION... /ISSUED 910 PM CDT FRI OCT 4 2013/ ..UPDATE... DISCUSSION... THUNDERSTORMS CONTINUED TO RIDE ALONG THE INITIAL WIND SHIFT OF THE COLD FRONT THIS EVENING FROM SOUTHWEST OKLAHOMA TO JUST WEST OF OSAGE COUNTY AS OF 9 PM THIS EVENING. THE DRIER AIR REMAINED FURTHER WEST ACROSS NORTHWEST OKLAHOMA. THESE THUNDERSTORMS WILL PUSH INTO THE CWA OVER THE NEXT HOUR AS THE FRONT CONTINUES TO PUSH EAST SOUTHEASTWARD. WITH THE LOSS OF DAYTIME HEATING THE CAP HAS BEGUN TO STRENGHTEN ACROSS THE CWA...HOWEVER DEEP LAYER SHEAR NEAR AND JUST BEHIND THE FRONT WILL ALLOW FOR THE POTENTIAL FOR SOME STORMS TO BECOME STRONG TO SEVERE. LARGE HAIL AND STRONG WINDS CONTINUE TO BE THE MAIN THREATS WITH THIS ACTIVITY. GREATEST POTENTIAL FOR ANY SEVERE STORMS LOOKS TO BE MAINLY NORTHWEST OF INTERSTATE 44 OVER THE NEXT FEW HOURS. THE SEVERE THUNDERSTORM WATCH FOR OSAGE AND PAWNEE COUNTIES REMAINS IN EFFECT UNTIL 3Z. LATEST RUNS OF THE HRRR AND THE LOCAL IN-HOUSE MODEL INDICATE THAT THUNDERSTORMS COULD BE NEAR EAST CENTRAL OKLAHOMA BY 06Z AND INTO SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS BY 9Z. INSTABILITY ACROSS THE REST OF THE CWA SHOULD WEAKEN OVERNIGHT AS THE CAP CONTINUES TO STRENGHTEN...THOUGH AN ISOLATED STRONG TO SEVERE STORM COULD BE POSSIBLE. GUSTY NORTHWESTERLY WINDS IN THE 20 TO 30 MPH RANGE HAVE BEEN OBSERVED BEHIND THE FRONT WITHIN THE DRIER/COOLER AIR AND WILL CONTINUE TO FILTER INTO THE REGION OVERNIGHT. TEMPERATURES BY EARLY SATURDAY MORNING LOOK BE AROUND 50 TO LOWER 50S NEAR THE KANSAS BORDER TO THE 60S FOR FAR SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. EVENING UPDATE WILL BE TO ADJUST POPS/WX/SKY GRIDS BASED ON LATEST TRENDS AND TIMING...WHILE THE REST OF THE FORECAST SEEMS TO BE HANDLING WELL AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... TUL 54 64 47 68 / 90 20 10 0 FSM 70 73 46 68 / 80 70 10 0 MLC 59 60 44 70 / 90 60 10 0 BVO 52 65 43 66 / 80 20 10 0 FYV 63 65 42 63 / 80 80 10 10 BYV 66 68 44 62 / 80 80 10 10 MKO 57 59 45 68 / 90 60 10 0 MIO 53 61 43 64 / 90 50 10 10 F10 55 60 46 69 / 90 40 10 0 HHW 71 73 46 72 / 80 50 10 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...18
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1023 PM EDT SUN OCT 6 2013 .SYNOPSIS... THE REGION REMAINS IN THE WARM SECTOR OF A LOW MOVING THROUGH THE UPPER GR LAKES. THE ASSOCIATED COLD FRONT WILL MOVE THROUGH ON MONDAY AS TROPICAL MOISTURE FLOWS UP INTO THE STATE. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE NEW WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE COLD FRONT IS MOVING INTO EASTERN OHIO ACCOMPANIED BY AN AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDERSTORMS. LOCALLY...THE CWA IS DRY AND QUITE MILD. HAVEN`T REALLY CHANGED MUCH OF THE FORECAST DURING THE OVERNIGHT...STILL LOOKS GOOD FOR RAIN TO BE MOVING INTO WESTERN AREAS AROUND OR SHORTLY AFTER 06Z...AND SPREADING QUICKLY EAST AFTER THAT. THE STRONG...SOUTHERLY LLJ WILL SHIFT EAST FROM THE OHIO VALLEY AND INTO THE REGION OVERNIGHT. THIS WILL QUICKLY INCREASE SFC WINDS...WITH THE HIGHER TERRAIN AND LOCATIONS NORTH OF GAPS IN THE RIDGES SEEING WIND GUSTS OVER 30 MPH. INCREASED LARGE SCALE LIFT ASSOCIATED WITH THIS LLJ AND A SERIES OF UPPER SHORT WAVES LIFTING QUICKLY NNE AHEAD OF THE MAIN OHIO VALLEY TROUGH AND SFC COLD FRONT WILL LEAD TO THE DEVELOPMENT OF NUMEROUS SHOWERS AND EMBEDDED LOW TOPPED TSRA OVER THE WESTERN PA AFTER MIDNIGHT. THIS CONVECTION MAY REACH THE I-99/RT 220 CORRIDOR BETWEEN 10-12Z MONDAY. LOOK FOR ONE MORE NIGHT OF UNSEASONABLY MILD TEMPS WITH LOW IN THE 60-65F RANGE...THANKS TO SIMILARLY HIGH DEWPOINTS...AND THE INCREASING CLOUDS/WIND. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... WIDESPREAD VFR CONDITIONS ACROSS CENTRAL PA THIS EVENING AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATE TONIGHT/EARLY MON. BIGGEST AVIATION CONCERN THROUGH EVENING HOURS WILL BE A GUSTY S/SE WIND...PEAKING AT AROUND 25 MPH AT TIMES. MOIST FLOW IS ALLOWING A MARINE LAYER FROM THE ATLANTIC TO PUSH NORTHWESTWARD ACROSS CWA...RAISING DEWPOINTS BY NEARLY 10F. BIGGER IMPACTS OF THIS MARINE LAYER WILL BE SEEN LATER TONIGHT...AS POTENT SOUTHERLY LOW-LEVEL JET SLIDES EAST FROM OHIO VALLEY...PROVIDING THE LIFT TO INITIATE DEVELOPMENT OF AN IFR STRATOCU DECK AS CONDITIONS DETERIORATE AHEAD OF APPROACHING TROUGH. SCT SHOWERS POSS IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. THEN FOCUS TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...LAMBERT/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
628 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... CURRENT 12Z RUNS STAY CONSISTENT IN TIMING THROUGH 06Z MONDAY. AFTER THAT PERIOD THE MODELS BEGIN TO DIVERGE IN TIMING...POSITION AND INTENSIFICATION. THE LATEST NAM SEEMS TO BE THE SLOWEST SOLUTION AND STALLS THE LARGE UPPER LEVEL LOWS PROGRESSION...WITH PASSAGE THROUGH PA EARLY TUESDAY. THE CANADIAN...EC AND GFS MOVE THE SYSTEM THROUGH 6 TO 12 HOURS FASTER. THE EC MOVES THE STRONGEST FORCING TO THE NORTH...AND POSITIVELY TILTS THE TROUGH AS MOVES EASTWARD. THE GFS AND CMC DEEPEN THE TROUGH AS SUCH MADE A TIMING CHANGE TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS IN THE LOWER SUSQ VALLEY. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. AS THE FRONT MOVES OVER THE MOUNTAINS LATE MORNING ON MONDAY...THERE IS A GOOD CHANCE FOR SCATTERED THUNDERSTORMS ALONG THE BOUNDARY. ALSO EXPECT PERIODS OF HEAVY RAINFALL AT AND BEHIND THE FRONT...MONDAY AFTERNOON AND EARLY EVENING. SPC HAS REMOVED THE SLIGHT RISK...THOUGH WITH THE HEAVY RAINFALL AND CONVECTION...WHICH SHOULD BE LOW TOPPED...CANNOT RULE OUT GUSTY WINDS ALONG THE FRONT. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... MAINLY VFR CONDS WITH LIGHT/VARIABLE WIND WILL CONTINUE THIS EVENING...THOUGH ISOLATED SHOWERS DRIFTING EAST ACROSS THE REGION COULD BRING A BRIEF BOUT OF MVFR CONDITIONS. WILL CONTINUE WITH THE MENTION OF VCSH AT MOST TAF SITES THROUGH 03Z-04Z...AND EVEN A TEMPO FOR HIGH END IFR CONDITIONS AT KJST BETWEEN 00-02Z...AS A CLUSTER OF TSRA /CURRENTLY INVOF KPIT/ TRACKS EWD AT 20-25KTS. CONVECTION WILL WANE DURING THE LATE EVENING WITH THE LOSS OF HEATING AND LACK OF ANY SIGNIFICANT LLVL BOUNDARY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS LATER TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/CERU AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
405 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... CURRENT 12Z RUNS STAY CONSISTENT IN TIMING THROUGH 06Z MONDAY. AFTER THAT PERIOD THE MODELS BEGIN TO DIVERGE IN TIMING...POSITION AND INTESIFICATION. THE LATEST NAM SEEMS TO BE THE SLOWEST SOLUTION AND STALLS THE LARGE UPPER LEVEL LOWS PROGRESSION...WITH PASSAGE THROUGH PA EARLY TUESDAY. THE CANADIAN...EC AND GFS MOVE THE SYSTEM THROUGH 6 TO 12 HOURS FASTER. THE EC MOVES THE STRONGEST FORCING TO THE NORTH...AND POSITIVELY TILTS THE TROUGH AS MOVES EASTWARD. THE GFS AND CMC DEEPEN THE TROUGH AS SUCH MADE A TIMING CHANGE TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS IN THE LOWER SUSQ VALLEY. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. AS THE FRONT MOVES OVER THE MOUNTAINS LATE MORNING ON MONDAY...THERE IS A GOOD CHANCE FOR SCATTERED THUNDERSTORMS ALONG THE BOUNDARY. ALSO EXPECT PERIODS OF HEAVY RAINFALL AT AND BEHIND THE FRONT...MONDAY AFTERNOON AND EARLY EVENING. SPC HAS REMOVED THE SLIGHT RISK...THOUGH WITH THE HEAVY RAINFALL AND CONVECTION...WHICH SHOULD BE LOW TOPPED...CANNOT RULE OUT GUSTY WINDS ALONG THE FRONT. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... VFR CONDS CONTINUE THIS AFTN WITH SCT-BKN 3-5KFT MOD CUMULUS BASES AND ISOLD/WDLY SCT CONVECTION DEVELOPING ACROSS THE AIRSPACE. BRIEF RESTRICTIONS TO MVFR/IFR ARE POSSIBLE UNDER DIRECT HITS FROM SHOWERS AND TSTMS. ADDED SOME VCSH MENTION BUT OVERALL CVRG IS LIMITED. AMDS WILL NEED TO BE ISSUED FOR BRIEF SHRA/TSRA IMPACTS. CONVECTION SHOULD WANE INTO THE EVE WITH THE LOSS OF INSTABILITY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/CERU AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... MADE A TIMING TWEAK TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. PREV DISC FOLLOWS... MAIN FEATURE FOR THE LONG TERM WILL BE A CLOSED UPPER LOW THAT SLOWLY MOVES FROM THE LOWER OHIO VALLEY TO THE ST. LAWRENCE VALLEY BY EARLY WEEK. THIS FEATURE WILL HELP DRAW SOME OF THE MOISTURE ASSOCIATED WITH TROPICAL STORM/DEPRESSION KAREN INTO THE AREA. WHILE NOT A DIRECT HIT OVER THE REGION...EXPECT STORM TOTAL AMOUNTS FROM LATE SUNDAY THROUGH TUESDAY TO BE IN THE 1 TO 1.5 INCH RANGE. LATEST MODELS DELAY THE ARRIVAL OF THE LEADING AREA OF PRECIPITATION/FRONTAL BOUNDARY TOWARD SUNDAY NIGHT. HAVE BACKED OFF POPS FOR SUNDAY AFTERNOON AS A RESULT. THIS WILL KEEP MILD AIR ACROSS THE REGION THROUGH THE WEEKEND. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDS CONTINUE THIS AFTN WITH SCT-BKN 3-5KFT MOD CUMULUS BASES AND ISOLD/WDLY SCT CONVECTION DEVELOPING ACROSS THE AIRSPACE. BRIEF RESTRICTIONS TO MVFR/IFR ARE POSSIBLE UNDER DIRECT HITS FROM SHOWERS AND TSTMS. ADDED SOME VCSH MENTION BUT OVERALL CVRG IS LIMITED. AMDS WILL NEED TO BE ISSUED FOR BRIEF SHRA/TSRA IMPACTS. CONVECTION SHOULD WANE INTO THE EVE WITH THE LOSS OF INSTABILITY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/TYBURSKI AVIATION...STEINBUGL
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
305 PM MDT SAT OCT 5 2013 .SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT ISSUED AT 301 PM MDT SAT OCT 5 2013 THE STORM CONTINUES TO WIND DOWN SLOWLY FOR THE BLACK HILLS REGION THIS AFTERNOON. A STRONG CLOSED LOW OVER EASTERN SOUTH DAKOTA IS MAKING A LITTLE PROGRESS EASTWARD THIS AFTERNOON. THE RESULT FOR THE WESTERN HALF OF THE STATE IS DECREASING SNOWFALL AND WIND AS THE WEAKENING BAND OF PRECIPITATION AND STRONG WIND SHFTS EASTWARD. THE 18Z HRRR SHOWS THE SURFACE LOW CENTER WEAKENING RAPIDLY AND REFORMING OVER MINNESOTA DURING THE NEXT SEVERAL HOURS. AS THE SYSTEM MOVES INTO CENTRAL SOUTH DAKOTA BOTH THE PRECIPITATION RATE AND DURATION OF STRONG WINDS ARE EXPECTED TO DECREASE RESULTING IN A LESS POTENT EVENT IN THOSE PARTS. A MUCH WELCOME DAY OF BLUE SKIES AND SUNSHINE ARE IN STORE FOR SUNDAY AS A TRANSITORY HIGH PRESSURE RIDGE SHIFTS INTO THE HIGH PLAINS. GUIDANCE WARMING SEEMS A LITTLE TOO AGRESSIVE CONSIDERING THE EXTENSIVE SNOWPACK WE`VE ACQUIRED SO TEMPS WERE TRIMMED DOWN A BIT. THIS IS BETTER THAN A RAPID MELTOFF ANYWAY. WILL HAVE TO KEEP AN EYE ON HOW THE STREAMS RESPOND OVER THE NEXT COUPLE OF DAYS. THE MILD SUNNY WEATHER IS FORECAST TO CONTINUE MONDAY AS THE RIDGE LINGERS OVER THE REGION. && .LONG TERM...MONDAY THROUGH SATURDAY ISSUED AT 301 PM MDT SAT OCT 5 2013 PROGRESSIVE LONG WAVE RIDGE BUILDS IN BEHIND THE RECORD-BREAKING BLIZZARD... MOVING QUICKLY FROM NEAR 110W ON MON TO JUST E OF 100W ON TUE AND TO 85W ON WED. AS IT DOES SO...A NEW LONG WAVE TROF IS CARVED OUT IN THE WEST. GFS CONTINUES TREND OF LAST SEVERAL RUNS IN SPLITTING OFF A NRN STREAM SHORT WAVE AND MOVING IT ACROSS WRN CAN WHILE THE STRONGER PORTION OF THE WAVE DIGS S WARD INTO CA. BY 12Z WED A CLOSED LOW IS SHOWN OVER NRN CA. THE DIGGING PROCESS IS COMPLETED BY THU AT 12Z AND THE LOW IS FCST TO MOVE OUT TO THE NE...PERHAPS TO SE SD BY 12Z SAT. THIS RUN OF GFS IS SLIGHTLY FARTHER S AND E THAN YESTERDAY`S. WHILE THE TRACK IS REMINISCENT OF OUR PRESENT STORM...1000 TO 500MB THICKNESSES ARE PRESENTLY FCST TO BE WELL ABOVE SNOW RELATED VALUES AND THE UPPER LOW IS FAR LESS INTENSE. BUT IT IS EARLY IN THE GAME. ACCEPTED THE EXTENDED INIT TEMPS...THOUGH THEY ARE MUCH BELOW GFS MOS GUIDANCE FOR WED AND THU. THINKING IS THAT THERE WILL STILL BE SOME WET GROUND FROM THE HEAVY SNOW AND THAT THE STORM-FOLLOWING RIDGE IS FCST TO MOVE E WARD SO QUICKLY THAT UPPER LEVEL COOLING WILL ALREADY BE UNDERWAY AS THE TROF IN THE W INTENSIFIES AND APPROACHES THE AREA. CLOUDS...POPS...AND PRECIP BROUGHT IN THU NIGHT INTO SAT IN LINE WITH APPROACHING CLOSED LOW. && .AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING ISSUED AT 301 PM MDT SAT OCT 5 2013 FOR 12Z TAF ISSUANCE. A WIDESPREAD AREA OF SNOW CONTINUES TO BLANKET THE AREA...AND VERY STRONG NORTHWEST WINDS ARE PERSISTING. LIFR AND IFR CONDITIONS WILL PREDOMINATE OVER WESTERN SD IN SNOW AND BLOWING SNOW THROUGH MID MORNING SATURDAY. PRECIPITATION WILL END FROM THE WEST WITH IMPROVING CEILINGS AND VISIBILITIES. BY SUNSET...EXPECT MOSTLY VFR CONDITIONS. STRONG WINDS WILL DIMINISH VERY SLOWLY DURING THE AFTERNOON SATURDAY. NO OBSERVATIONS HAVE BEEN AVAILABLE SINCE FRIDAY AFTERNOON FROM KRAP DUE TO COMMUNICATIONS ISSUES. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR SDZ044. WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR SDZ046- 047-049. BLIZZARD WARNING UNTIL 6 PM MDT THIS EVENING FOR SDZ014-032-043. WY...NONE. && $$ SHORT TERM...CARPENTER LONG TERM...BARBER AVIATION...BARBER
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
721 PM CDT SUN OCT 6 2013 .UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REMOVE THE THROUGH LATE AFTERNOON WORDING AND TO TAILOR SHWRS PRESENTLY MAINLY E OF I-65 TO CONTINUE SLOWING MOVING EWD OUT OF MID STATE WITH SHWRS CONTINUING ACROSS THE PLATEAU COUNTIES ONLY GENERALLY AFTER MIDNIGHT. HAVE TAILORED SKY CONDITIONS ALSO TO REFLECT DECREASING CLOUDINESS W TO E ACROSS THE MID STATE AS THE NIGHT TIME HRS PROGRESS. CURRENT TEMPS IN LINE WITH FORECASTED LOW VALUES AS OF THIS TIME...THUS NO ADJUSTMENTS MADE TO OVERNIGHT LOW VALUES AS OF THIS TIME. && .PREV DISCUSSION.../ISSUED 638 PM CDT SUN OCT 6 2013/ UPDATE...FOR AVIATION. AVIATION... 00Z TAFS...SHRA HAVE ENDED AT CKV...AND ABOUT TO END FOR BNA. SHRA AND COLD FRONT NOW APPROACHING CSV. FOR BNA AND CKV...MAINLY VFR CONDITIONS THROUGH THE NEXT 24 HOURS WITH DRIER AIR AND HIGH PRESSURE. SOME DAYBREAK MVFR FOG IS POSSIBLE. AFTER 15Z...LOOK FOR EXCELLENT VSBY...FEW-SCT FAIR WX CU AND NNW WINDS NEAR 10KT. CSV WILL BEGIN WITH SEVERAL HOURS OF VARYING MVFR/IFR CONDITIONS WITH SHRA AND PERHAPS A BRIEF TSRA. RAIN IS EXPECTED TO MOVE OUT BY 06Z...BUT SOME MVFR CIGS/VSBYS MAY PERSIST THROUGH THE NIGHT. DAYTIME MONDAY WILL BRING EXCELLENT VSBY...SCT CU AND NW WINDS NEAR 10KT. 13 PREV DISCUSSION... /ISSUED 511 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO INTRODUCE A THROUGH THE LATE AFTERNOON HOURS GROUPING ALL COUNTIES TO DEAL WITH CURRENT AND EXPECTED SHORT TERM PROGRESSION OF SHWRS AND ISO TSTMS W TO E ACROSS MID STATE. TEMPS SHOULD FALL ACROSS THE ENTIRE MID STATE INTO THE UPPER 50S BY THE LATE AFTERNOON HRS. ALSO. 31 PREV DISCUSSION.../ISSUED 213 PM CDT SUN OCT 6 2013/ DISCUSSION...SURFACE FRONT HAS MADE IT EAST OF NASHVILLE, WITH A BROKEN LINE OF MODERATE TO HEAVY SHOWERS OCCURRING ALONG THE BOUNDARY. HRRR DOING A REASONABLE JOB WITH ONGOING ACTIVITY, AND THE SHORT-RANGE MODEL SHOWS NUMEROUS CELLS LASTING WELL PAST 00Z. SIGNIFICANTLY COOLER AIR AND LOWER DEW POINTS ARE OBVIOUSLY RUSHING IN BEHIND THE FRONT, EVEN AS SCATTERED SHOWERS CONTINUE DEVELOPING IN THE COLD POOL. EXPECT MOST OF THE ACTIVITY TO MOVE EAST OF THE AREA BY 06Z, WITH SHOWERS EXITING THE PLATEAU BY 12Z. A BROAD RIDGE OF HIGH PRESSURE WILL QUICKLY BUILD IN AND DRY OUT THE ATMOSPHERE AND KEEP A COOLER AIR MASS LOCKED IN PLACE OVER MIDDLE TENNESSEE THE REMAINDER OF THE WEEK. NO PRECIPITATION IS EXPECTED FROM TOMORROW THROUGH THE END OF THE 7-DAY FORECAST PERIOD. ROSE && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
638 PM CDT SUN OCT 6 2013 .UPDATE...FOR AVIATION. && .AVIATION... 00Z TAFS...SHRA HAVE ENDED AT CKV...AND ABOUT TO END FOR BNA. SHRA AND COLD FRONT NOW APPROACHING CSV. FOR BNA AND CKV...MAINLY VFR CONDITIONS THROUGH THE NEXT 24 HOURS WITH DRIER AIR AND HIGH PRESSURE. SOME DAYBREAK MVFR FOG IS POSSIBLE. AFTER 15Z...LOOK FOR EXCELLENT VSBY...FEW-SCT FAIR WX CU AND NNW WINDS NEAR 10KT. CSV WILL BEGIN WITH SEVERAL HOURS OF VARYING MVFR/IFR CONDITIONS WITH SHRA AND PERHAPS A BRIEF TSRA. RAIN IS EXPECTED TO MOVE OUT BY 06Z...BUT SOME MVFR CIGS/VSBYS MAY PERSIST THROUGH THE NIGHT. DAYTIME MONDAY WILL BRING EXCELLENT VSBY...SCT CU AND NW WINDS NEAR 10KT. 13 && .PREV DISCUSSION... /ISSUED 511 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO INTRODUCE A THROUGH THE LATE AFTERNOON HOURS GROUPING ALL COUNTIES TO DEAL WITH CURRENT AND EXPECTED SHORT TERM PROGRESSION OF SHWRS AND ISO TSTMS W TO E ACROSS MID STATE. TEMPS SHOULD FALL ACROSS THE ENTIRE MID STATE INTO THE UPPER 50S BY THE LATE AFTERNOON HRS. ALSO. 31 PREV DISCUSSION.../ISSUED 213 PM CDT SUN OCT 6 2013/ DISCUSSION...SURFACE FRONT HAS MADE IT EAST OF NASHVILLE, WITH A BROKEN LINE OF MODERATE TO HEAVY SHOWERS OCCURRING ALONG THE BOUNDARY. HRRR DOING A REASONABLE JOB WITH ONGOING ACTIVITY, AND THE SHORT-RANGE MODEL SHOWS NUMEROUS CELLS LASTING WELL PAST 00Z. SIGNIFICANTLY COOLER AIR AND LOWER DEW POINTS ARE OBVIOUSLY RUSHING IN BEHIND THE FRONT, EVEN AS SCATTERED SHOWERS CONTINUE DEVELOPING IN THE COLD POOL. EXPECT MOST OF THE ACTIVITY TO MOVE EAST OF THE AREA BY 06Z, WITH SHOWERS EXITING THE PLATEAU BY 12Z. A BROAD RIDGE OF HIGH PRESSURE WILL QUICKLY BUILD IN AND DRY OUT THE ATMOSPHERE AND KEEP A COOLER AIR MASS LOCKED IN PLACE OVER MIDDLE TENNESSEE THE REMAINDER OF THE WEEK. NO PRECIPITATION IS EXPECTED FROM TOMORROW THROUGH THE END OF THE 7-DAY FORECAST PERIOD. ROSE && .OHX WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1154 AM CDT SAT OCT 5 2013 .AVIATION... BASED ON CURRENT MVMT...FRONT SHOULD BE NEAR CLL AROUND 21Z...IAH 2Z & GLS 5Z. MODELS SHOWING SOME SPOTTY SHRA GENERALLY E OF HWY 288 & I-45 THRU THE DAY AND KEPT VCSHS IN TAFS. DID LOWER CIGS OVERNIGHT IN THE WAKE OF THE FRONT INTO MVFR & HIGH IFR TERRITORY AS SOME MOISTURE GETS TRAPPED BELOW SHARP INVERSION. WILL ALSO BE KEEPING AN EYE ON THE POTENTIAL FOR SOME POST FRONTAL PRECIP (WITH H85 FRONT LOOKING TO BE FOCUS) OVERNIGHT. MAJORITY OF MODELS THAT DO SHOW THIS OCCURRING KEEP IT MOSTLY WEST AND EAST OF OUR TERMINALS. WILL LEAVE MENTION OUT OF 18Z TAFS ATTM AND SEE HOW IT PLAYS OUT. LOOK CIGS TO LIFT & CLEAR OUT FROM NW-SE FROM MID MORNING THRU MID/LATE AFTN SUNDAY. 47 && .PREV DISCUSSION... /ISSUED 1021 AM CDT SAT OCT 5 2013/ THE COLD FRONT WAS PROGRESSING STEADILY ACROSS THE NORTHERN AND CENTRAL PORTIONS OF THE STATE. UPDATED THE WIND SHIFT WITH THE LATEST RAP FORECAST. A 12Z ANALYSIS SHOWED A SURFACE RIDGE OVER THE TEXAS COASTAL AREAS WITH LOW-LEVEL MOISTURE STREAMING NORTHWARD FROM THE GULF INTO AREAS MAINLY EAST OF FREEPORT. OVER MOST OF THE FORECAST AREA THE AIR MASS WAS FAIRLY DRY AND CAPPED AND EXPECT THAT MOST CONVECTION THIS AFTERNOON WILL BE CONFINED TO THE EASTERN AND NORTHERN SET OF COUNTIES WHERE THE DEEPER MOISTURE AND COOLER AIRMASS ALOFT RESIDES. WILL UPDATE MAINLY FOR THE WINDS. OTHERWISE...THE REMAINDER OF THE FORECAST LOOKS ON TARGET. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 89 58 81 52 83 / 20 20 10 0 0 HOUSTON (IAH) 92 62 80 53 83 / 50 30 10 0 0 GALVESTON (GLS) 89 69 81 65 80 / 40 30 20 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1021 AM CDT SAT OCT 5 2013 .DISCUSSION... THE COLD FRONT WAS PROGRESSING STEADILY ACROSS THE NORTHERN AND CENTRAL PORTIONS OF THE STATE. UPDATED THE WIND SHIFT WITH THE LATEST RAP FORECAST. A 12Z ANALYSIS SHOWED A SURFACE RIDGE OVER THE TEXAS COASTAL AREAS WITH LOW-LEVEL MOISTURE STREAMING NORTHWARD FROM THE GULF INTO AREAS MAINLY EAST OF FREEPORT. OVER MOST OF THE FORECAST AREA THE AIR MASS WAS FAIRLY DRY AND CAPPED AND EXPECT THAT MOST CONVECTION THIS AFTERNOON WILL BE CONFINED TO THE EASTERN AND NORTHERN SET OF COUNTIES WHERE THE DEEPER MOISTURE AND COOLER AIRMASS ALOFT RESIDES. WILL UPDATE MAINLY FOR THE WINDS. OTHERWISE...THE REMAINDER OF THE FORECAST LOOKS ON TARGET. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 89 58 81 52 83 / 20 20 10 0 0 HOUSTON (IAH) 92 62 80 53 83 / 50 30 10 0 0 GALVESTON (GLS) 89 69 81 65 80 / 40 30 20 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...40 AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
100 PM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT SATURDAY... SHOULD BE A WARM...POTENTIALLY RECORD BREAKING DAY...ESPECIALLY AT BLACKSBURG/BLUEFIELD (SEE CLIMATE SECTION BELOW)...AS HIGH PRESSURE RESIDES OVERHEAD. FOG WILL BE LIFTING ACROSS THE VALLEYS...BUT HAS HELD STRONG IN THE GREENBRIER VALLEY. TEMPS STARTING TO RUN A COUPLE DEGREES WARMER OUT EAST THAN CURRENT FORECAST...SO BUMPED UP HIGHS A COUPLE DEGREES...LOOKING AT UPPER 70S TO LOWER 80S ACROSS THE HIGHER TERRAIN...TO MID TO UPPER 80S VALLEYS AND POINTS EAST OF THE BLUE RIDGE. PREVIOUS VALID DISCUSSION... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS THROUGH TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. ANY SCATTERED TO BROKEN CU THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... AS OF 100 PM EDT SATURDAY... AXIS OF UPPER RIDGE WILL CROSS THE AREA AS WE BEGIN TO COME UNDER THE INFLUENCE OF UPSTREAM SYSTEM APPROACHING FROM THE MIDWEST. THERE WILL BE A LITTLE SHORT WAVE ENERGY MOVING THROUGH THE ARE EARLY IN THE TAF PERIOD...BUT SIGNIFICANT MOISTURE IS LACKING AND CAPES ARE MEAGER. WHILE AN ISOLATED SHOWER CAN NOT BE RULED OUT IT DOES NOT WARRANT A MENTION IN THE TAFS. WILL GO WITH BKN VFR CIGS WEST AND NORTH WITH JUST SCT EAST AND SOUTH. EXPECTING MID/HIGH CLOUDS TO REMAIN MOSTLY TO OUR NORTH AND ALLOW FOR DECENT RAD COOLING OVERNIGHT. THUS...EXPECTING KLWB/KBCB TO FOG IN AGAIN TONIGHT BUT ONLY MVFR AT OTHER SITES. SHOULD STAY VFR AT KBLF AS WINDS COME AROUND TO A SWLY DIRECTION TO PROHIBIT FOG. .EXTENDED AVIATION... LOOKS LIKE COLD FRONT APPROACHING FROM THE WEST WILL BE THE MAIN PLAYER FOR OUR WEATHER SUNDAY NIGHT THROUGH MONDAY AS TROPICAL SYSTEM REMAINS TO OUR SOUTH. AVIATION CONDITIONS WILL BE QUITE POOR THIS PERIOD WITH RAIN...GUSTY WINDS...AND LIKELY IFR CONDITIONS. HOWEVER...THINGS WILL IMPROVE CONSIDERABLY BEHIND THE FRONT TUESDAY...AND THE REMAINDER OF THE WEEK LOOKS GOOD FOR AVIATION WITH THE EXPECTATION OF DIURNAL FOG FORMATION. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...JH/WP AVIATION...MBS CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1017 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT SATURDAY... SHOULD BE A WARM...POTENTIALLY RECORD BREAKING DAY...ESPECIALLY AT BLACKSBURG/BLUEFIELD (SEE CLIMATE SECTION BELOW)...AS HIGH PRESSURE RESIDES OVERHEAD. FOG WILL BE LIFTING ACROSS THE VALLEYS...BUT HAS HELD STRONG IN THE GREENBRIER VALLEY. TEMPS STARTING TO RUN A COUPLE DEGREES WARMER OUT EAST THAN CURRENT FORECAST...SO BUMPED UP HIGHS A COUPLE DEGREES...LOOKING AT UPPER 70S TO LOWER 80S ACROSS THE HIGHER TERRAIN...TO MID TO UPPER 80S VALLEYS AND POINTS EAST OF THE BLUE RIDGE. PREVIOUS VALID DISCUSSION... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS THROUGH TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. ANY SCATTERED TO BROKEN CU THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 740 AM EDT SATURDAY... NEW RIVER AND GREENBRIER VALLEYS HAD DENSE FOG THIS MORNING... INCLUDING LIFR VISIBILITIES AT KBCB AND KLWB. EXPECT IMPROVEMENT IN CONDITIONS BY 10AM. ONCE FOG MIXES OUT THIS MORNING...HIGH CONFIDENCE THAT THE REST OF THE DAY WILL BE VFR. HAVE ADDED FOG IN AGAIN FOR TONIGHT IN KLWB AND KBCB, WITH DEW POINTS GRADUALLY RISING...THERE IS A POSSIBILITY FOR MVFR FOG AT KDAN AND KLYH AFTER 06Z2AM TONIGHT. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
746 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY AND TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM EDT SATURDAY... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS TODAY AND TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. DEEP SOUTHWEST WINDS THIS AFTERNOON...EVEN THOUGH WIND SPEEDS WILL NOT BE VERY STRONG...WILL PROVIDE SOME DOWNSLOPNIG AND COMPRESSION. COMBINED WITH 850 MB TEMPERATURES OF +16 TO +18...MAXIMUM TEMPERATURES WILL AGAIN BE WELL ABOVE NORMAL. EXPECTING SIMILAR TEMPERATURES COMPARED TO FRIDAY...AND POSSIBLY A DEGREE OR TWO HIGH AS LONG AS THERE IS NOT CLOUD COVER. ANY SCATTERED TO BROKEN STRATOCUMULUS THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 740 AM EDT SATURDAY... NEW RIVER AND GREENBRIER VALLEYS HAD DENSE FOG THIS MORNING... INCLUDING LIFR VISIBILITIES AT KBCB AND KLWB. EXPECT IMPROVEMENT IN CONDITIONS BY 10AM. ONCE FOG MIXES OUT THIS MORNING...HIGH CONFIDENCE THAT THE REST OF THE DAY WILL BE VFR. HAVE ADDED FOG IN AGAIN FOR TONIGHT IN KLWB AND KBCB, WITH DEW POINTS GRADUALLY RISING...THERE IS A POSSIBILITY FOR MVFR FOG AT KDAN AND KLYH AFTER 06Z2AM TONIGHT. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
456 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY AND TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM EDT SATURDAY... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS TODAY AND TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. DEEP SOUTHWEST WINDS THIS AFTERNOON...EVEN THOUGH WIND SPEEDS WILL NOT BE VERY STRONG...WILL PROVIDE SOME DOWNSLOPNIG AND COMPRESSION. COMBINED WITH 850 MB TEMPERATURES OF +16 TO +18...MAXIMUM TEMPERATURES WILL AGAIN BE WELL ABOVE NORMAL. EXPECTING SIMILAR TEMPERATURES COMPARED TO FRIDAY...AND POSSIBLY A DEGREE OR TWO HIGH AS LONG AS THERE IS NOT CLOUD COVER. ANY SCATTERED TO BROKEN STRATOCUMULUS THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... AS OF 130 AM EDT SATURDAY... TEMPERATURE/DEW POINT SPREAD WAS ALREADY CLOSE TO ZERO AT KBCB/KLYH AND KDAN. HIGH CONFIDENCE OF IFR TO LIFR FOG ALONG AREA RIVERS EARLY THIS MORNING WHICH WILL RESULT IN LIFR VISIBILITIES AT KBCB AND KLWB. ONCE FOG MIXES OUT IN THE MORNING THE REST OF THE DAY WILL BE VFR. TIMING OF HOW FAST FOG LIFTS SHOULD BE BETWEEN 8AM AND 10AM. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
615 PM CDT SUN OCT 6 2013 .SHORT TERM...(TONIGHT AND MONDAY) ISSUED AT 255 PM CDT SUN OCT 6 2013 UPPER LEVEL LOW PRESSURE SYSTEM WAS CHURNING EAST ACROSS IA/NORTHERN ILL THIS AFTERNOON...WHILE THE SFC LOW WAS DISPLACED NORTHEAST OVER THE UP OF MICH. UPPER LEVEL ENERGY AND MOISTURE WRAPPED AROUND THE SYSTEM WAS RESULTING IN BANDS OF MOSTLY LIGHT RAIN SHOWERS NORTH-SOUTH ACROSS MN/IA. THE SYSTEM WILL CONTINUE TO TRACK TO THE EAST...DRAGGING THE LIGHT PCPN ACROSS THE FORECAST AREA AS IT GOES. EXPECT SOME DIMINISHING TREND LATE THIS EVENING...GRADUALLY ENDING AS IT WEAKENS AND MOVES EAST OVERNIGHT. AMOUNTS WILL BE MINIMAL. HIGH PRESSURE BUILDS ACROSS THE REGION ON MONDAY...WITH AMPLE SUNSHINE FOR MOST LOCATIONS TO KICK OFF THE NEW WORK WEEK. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 255 PM CDT SUN OCT 6 2013 FAIRLY QUIET FOR THE BETTER PART OF THE WORK WEEK...WITH LONGWAVE RIDGE IN THE EAST AND TROUGH TO THE WEST. PRESSURE GRADIENT ALREADY TIGHTENING BY TUESDAY...AND WILL STAY THAT WAY THROUGH FRIDAY. SHOULD BE A FAIRLY BREEZY WEEK AS A RESULT...BUT THESE SOUTHERLY WINDS WILL ALSO USHER MILDER AIR BACK INTO THE UPPER MISSISSIPPI RIVER VALLEY. NOT EXPECTING 80S...BUT LOWER 70S ARE LIKELY FOR THE LATER PART OF THE WORK WEEK. PRETTY NICE FALL CONDITIONS...SANS THE WINDS...FOR THE NEXT FEW DAYS. THE TROUGH MOVES OFF THE WEST COAST AND OVER THE CENTRAL U.S. BY FRIDAY...WITH THE 500 MB LOW LIFTING OVER THE NORTHERN PLAINS. GFS/EC/GEM ALL DEVELOP PCPN IN RESPONSE TO THE SYSTEM/S WARM FRONT/WARM AIR ADVECTION WING...EXTENDING SOUTHEAST OF THE STACKED LOW. THERE IS SOME DISAGREEMENT IN TIMING/STRENGTH OF THE SYSTEM AND THE PCPN...ALTHOUGH ALL DO SUGGEST THAT THERE WILL BE SOME RAIN CHANCES AS IT MOVES THROUGH. WILL LEAN ON THE CONSENSUS SOLUTION FOR NOW. ANY FROST/VALLEY FOG POTENTIAL LOOKS LIMITED THIS WEEK WITH THE INCREASING WINDS PUTTING A DAMPER ON THE CHANCES. TUESDAY MORNING HOLDS THE MOST PROMISE...WITH HIGH PRESSURE OVER WI AND WINDS STILL LIGHT EAST OF THE MISSISSIPPI RIVER VALLEY. HIGH POTENTIAL IN THE USUAL COLD SPOTS OF CENTRAL/NORTH-CENTRAL WI. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 615 PM CDT SUN OCT 6 2013 THE UPPER LEVEL LOW WAS OVER EASTERN IOWA LATE THIS AFTERNOON. THE DEFORMATION CLOUDS AND LIGHT RAIN/DRIZZLE ON THE BACK SIDE OF THE LOW EXTENDED FROM SOUTH CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN. AS THE UPPER LEVEL LOW MOVES OFF TO THE EAST/SOUTHEAST TONIGHT IT WILL DRAG THE LOW CLOUDS IN THE DEFORMATION AREA ACROSS THE REGION. SHOULD SEE THE CEILINGS DROP DOWN TO IFR AT KRST AND MVFR AT KLSE. COULD ALSO SEE A BRIEF REDUCTION IN THE VISIBILITY...BUT NOT EXPECTING THIS TO LAST VERY LONG OR VERY CONFIDENT ON WHEN IT MAY OCCUR...SO HAVE OPTED TO STAY WITH VFR VISIBILITIES FOR NOW. MODEL CONSENSUS BETWEEN THE 06.20Z RAP AND 06.18Z NAM IS FOR THE LOW CLOUDS IN THE DEFORMATION AREA TO CLEAR OUT BEFORE SUNRISE WITH CLEAR SKIES EXPECTED FOR THE REMAINDER OF THE PERIOD AS HIGH PRESSURE BUILDS IN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1213 PM CDT SAT OCT 5 2013 .UPDATE... THE WARM FRONT IS INCHING NORTHWARD THIS MORNING. DENSE FOG IN SOUTHEAST WI IMPROVED TO 1 TO 2 MILES...WHILE SHEBOYGAN AND PORT WASHINGTON REMAIN SOCKED IN WITH THE LIGHT SOUTHEAST FLOW OFF THE LAKE ON THE NORTH SIDE OF THE WARM FRONT. DENSE FOG ADVISORY IN EFFECT UNTIL MID AFTERNOON THERE. STRENGTHENING LOW LEVEL JET AND MOISTURE CONVERGENCE WITH A VORT MAX MOVING OUT OF EASTERN IOWA IS LEADING TO INCREASING SHOWER COVERAGE IN SOUTH CENTRAL WISCONSIN LATE THIS MORNING. THESE SHOWERS WILL EXPAND/PROGRESS EASTWARD THROUGH EARLY AFTERNOON. 1000 J/KG OF MU CAPE ALLOWING FOR A FEW EMBEDDED THUNDERSTORMS. WATCHING THE MORE DISCRETE CELLS IN NORTH CENTRAL IL FOR STRENGTHENING...AS THAT REGION HAS HIGHER CAPE AND BULK SHEAR VALUES. THESE VALUES WILL GRADUALLY MOVE INTO SOUTHERN WI...BUT FOG AND LOW CLOUDS OVER SOUTHERN WI WILL SLOW IT DOWN. LATEST HRRR KEEPS THE FORECAST REFLECTIVITY FOR MIDDAY RATHER LIGHT. HIGH PRECIPITABLE WATER VALUES WILL LEAD TO EFFICIENT RAINFALL THOUGH...SO WILL NEED TO WATCH FOR FLOODING POTENTIAL ESPECIALLY IN URBAN AREAS. WATER VAPOR IMAGERY SHOWS A STRONGER SHORTWAVE DOWN IN MISSOURI THAT IS NOW FORECAST TO MOVE THROUGH NORTHEAST IL AROUND 00Z ALONG THE SURFACE FRONTAL TROUGH INSTEAD OF SOUTHEAST WI. HOWEVER...THE SURFACE TROUGH WILL EXTEND BACK INTO WEST CENTRAL WI...SO WHILE THE STRONGEST 500MB SHORTWAVE WILL BE ABSENT...THERE WILL STILL BE SURFACE CONVERGENCE...MODERATE BULK SHEAR...UPPER DIVERGENCE AND STRONG 700MB OMEGA OVER SOUTHERN WI AT 00Z TO ALLOW FOR THUNDERSTORMS. ANOTHER ROUND OF WIDESPREAD CONVECTION IS EXPECTED WITH THIS FEATURE...MOST LIKELY BETWEEN 05 PM AND 10 PM IN THE MKX FORECAST AREA. THIS WILL BE THE PERIOD FOR HEAVIEST RAIN AND STRONGEST WIND GUSTS AND BEST POTENTIAL FOR SEVERE GUSTS. UNIDIRECTIONAL WIND THROUGH THE COLUMN WILL LEAD TO THUNDERSTORMS QUICKLY DEVELOPING INTO LINE SEGMENTS. && .AVIATION/18Z TAFS/... FOG CONTINUES TO THIN EXCEPT TOWARD SHEBOYGAN AND PORT WASHINGTON AHEAD OF THE WARM FRONT AND WITH THE INFLUENCE OF MARINE AIR. CIGS WILL REMAIN IFR OR LOWER UNTIL SCATTERED SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS SPREAD ACROSS SOUTH CENTRAL AND SOUTHEAST WI THROUGH EARLY AFTERNOON. ANOTHER ROUND OF WIDESPREAD CONVECTION WITH HEAVY RAIN AND STRONG WIND GUSTS WILL IMPACT SOUTHERN WI BETWEEN 5 PM TO 10 PM. CONVECTION WILL END FROM WEST TO EAST SOON AFTER MIDNIGHT AS OCCLUDED FRONT SLIDES EAST OF AREA. && .MARINE... WILL CONTINUE DENSE FOG ADVY INTO THE EVENING AS WARM...MOIST AIR CONTINUES TO MOVE ACROSS COOLER NEAR SHORE WATERS OF LAKE MI. SCATTERED MORNING AND EARLY AFTN CONVECTION WL GIVE WAY TO A MORE WIDESPREAD PERIOD LATER THIS AFTN AND EVE. && .PREV DISCUSSION... /ISSUED 305 AM CDT SAT OCT 5 2013/ TODAY AND TONIGHT - CONFIDENCE...MEDIUM. WL EXPAND DENSE FOG ADVY INTO MORE OF SOUTHEAST THROUGH THE EARLY MORNING AND CONTINUE 14Z EXPIRATION. AS WARM FRONT IN NORTHERN IL BEGINS TO SHIFT NWD...DENSE FOG SHOULD THIN THROUGH THE MORNING...BUT NORTHERN AREAS MAY NEED TO BE EXTENDED A FEW HOURS. OTRW...WEAKER WARM AIR ADVECTION WL CARRY NMRS CONVECTION ACROSS WRN CWA EARLY THIS MRNG...HOWEVER FOCUS OF WAA REMAINS OVER NRN HALF OF WI EARLY. LOW LEVEL JET STRENGTHENS ONCE AGAIN AHEAD OF STRONG UPPER LOW OVER NORTHERN PLAINS LATER THIS MRNG AND AFTERNOON ACROSS NRN IL/SRN WI REGION. SFC LOW SLIGHTLY WWD POSITION AT 12Z COMPARED TO EARLIER RUNS...AND 00Z NAM CONTINUES TO ADJUST ITS TIMING AND POSITION TO MORE FAVORED GFS AND ECMWF. INCREASING SOUTH WINDS AHEAD OF SFC LOW WL ALLOW WARM FRONT OVER NRN IL TO MOVE NWD ACROSS PORTIONS OF SRN WI TODAY AS SURFACE OCCLUSION BEARS DOWN ON THE AREA. OCCLUSION MAKES SLOW EWD PROGRESS TODAY...AND LOOKS LIKE IT WILL EXIT ERN CWA AROUND 06Z. STRONGER LAYER Q-VECTOR CONVERGENCE SPREADS IN THIS AFTN AND TNGT WITH OCCLUSION AND UPPER LEVEL SHORT WAVE. MUCAPE CURRENTLY AROUND 500 J/KG EXPECTED TO INCREASE TO 1500-2000 J/KG LATER TODAY AHEAD OF OCCLUSION. NO PROBLEM WITH AVAILABLE SHEAR FAVORING MULTICELLS AND SUPERCELLS MODE. IF LOW CLOUDS CLEAR OUT IN TIME ACROSS PORTIONS OF THE CWA...SHEAR AND INSTABILITY SHOULD BE ENOUGH TO TRIGGER STRONG TO SEVERE CONVECTION. CAN NOT RULE OUT A TORNADO CONSIDERING STRENGTH OF FORCING. PWAT REMAINS OVER 200 PERCENT OF NORMAL...SO IF EXPECTED NORTH TO SOUTH LINE OF CONVECTION LINGERS OVER AREA...POTENTIAL FOR FLASH FLOODING. WARM CLOUD DEPTH PRIOR TO AFTN CONVECTION OVER 11K FEET. FORTUNATELY HEAVIEST RAINFALL OF THE PAST SEVERAL DAYS HAS BEEN MOSTLY WEST AND SOUTH OF CWA. WILL CONTINUE SMALLER THREAT FOR CONVECTION LATE TONIGHT IN ERN CWA DUE TO LINGERING LOW LEVEL JET IN THE AREA. SUNDAY - CONFIDENCE...MEDIUM SLOW MOVING NEARLY STACKED LOW PROGGD TO TRAVERSE FROM WESTERN IOWA INTO CNTRL IL THROUGH SUNDAY NIGHT. PLENTY OF DRY AIR WRAPPING AROUND THIS SYSTEM WITH DRY SLOT ACRS MUCH OF WI. 850 COLD ADVECTION FROM THE SOUTHWEST. SOME MODELS SHOW CLOSE TO ZERO CELSIUS TOWARDS THE IL BORDER BY LATER SUNDAY NIGHT. THE NAM MODEL IS THE ONLY MODEL TO DEVELOP SOME DEF ZONE PRECIP SUNDAY NIGHT WITH A BIT MORE 700 RH ON THE NORTHERN SIDE OF THE SYSTEM THAN THE OTHER MODELS. SURFACE TROUGH AXIS EXTENDS ACROSS NRN AND WRN WI SO GIVEN THE PROGGD PLACEMENT OF DRY RH AND QPF...WILL REMOVE POPS FOR SUNDAY BUT LEAVE THEM IN FOR SUNDAY NIGHT. MONDAY - CONFIDENCE...MEDIUM MODEL CONSENSUS IS TO MOVE LOW FROM CNTRL IL INTO NE IN. BROAD 850 MILLIBAR CIRCULATION BECOMES CLOSED ACROSS LWR MI DURING THE AFTERNOON. SURFACE/850 TROUGH EXTENDS FROM THE LWR MI LOW INTO CNTRL/SRN WI ENHANCING LOW LEVEL FORCING. IN ADDITION TO THE RIPPLES WRAPPING WEST AND SOUTHWEST AROUND THE PERIPHERY OF THE UPPER LOW CENTER. SO WILL HAVE CHANCE POPS FOR SHRA IN THIS PATTERN. THE 00Z ECMWF HAS THROWN A BIT OF A WRENCH INTO THINGS BY COMING IN WITH A MUCH MORE PROGRESSIVE SOLUTION HOWEVER GIVEN THE CURRENT LOCATION AND STRUCTURE OF THIS SYSTEM WOULD APPEAR THAT LEANING TOWARDS A SLOWER SOLUTION HAS MORE CREDENCE AT THIS POINT. WILL NOT JUMP ON THIS NEW ECMWF DEVELOPMENT YET ESP WITH THE NAM/GFS/GEM ALL SHOWING A SLOWER LOOK. TUESDAY - CONFIDENCE...MEDIUM LOW PLODS INTO THE EASTERN GREAT LAKES WITH CYCLONIC FLOW ON THE WESTERN SIDE STILL LINGERING INTO EASTERN WI. ALLBLEND HAS SOME SLIGHT POPS IN THE EAST AND FOR NOW THIS IS FINE. WITH THE FASTER 00Z ECMWF WAS TEMPTED TO PULL THIS POP BUT AFTER COORD WITH LOT/GRB WAS DECIDED TO LEAVE THIS AS IS FOR NOW AND STICK WITH THE CONSENSUS. APPEARS INFLUENCE OF THE UPPER CIRCULATION GETS FAR ENOUGH AWAY WITH SURFACE RIDGING BUILDING IN FOR THE AFTERNOON. WEDNESDAY THROUGH FRIDAY - CONFIDENCE...MEDIUM SURFACE/850 HIGH CENTERED OVER THE AREA ON WEDNESDAY. WITH A SHIFT TO THE EAST ON THURSDAY AND FRIDAY...THIS SETS UP A RETURN SOUTHERLY FLOW WHICH BRINGS MILDER 925 TEMPS INTO THE AREA. AVIATION/12Z TAFS/...AREAS OF DENSE FOG WILL GRADUALLY THIN THIS MORNING AS WINDS INCREASE AS WARM FRONT IN NRN IL ADVANCES NORTH. CIGS MAY EVEN INCREASE TO VFR FOR A TIME BEFORE NMRS CONVECTION SPREADS IN LATE MRNG AND AFTN. CONVECTION SHOULD END OVERNIGHT WRN AREAS AS OCCLUDED FRONT SLIDES EAST OF AREA. MARINE...WL CONTINUE DENSE FOG ADVY INTO THE AFTN AS WARM...MOIST AIR CONTINUES TO MOVE ACROSS COOLER NEAR SHORE WATERS OF LAKE MI. SCATTERED MORNING AND EARLY AFTN CONVECTION WL GIVE WAY TO A MORE WIDESPREAD PERIOD LATER THIS AFTN AND EVE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR WIZ052-060. LM...DENSE FOG ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643>646. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...MBK SUNDAY THROUGH FRIDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTI-CELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1150 AM CDT SAT OCT 5 2013 FRONTAL BOUNDARY WILL CONTINUE TO ROTATE NORTHEAST ACROSS THE REGION THIS AFTERNOON. ITS ALREADY CLEARED KRST...AND WILL DO SO AT KLSE BY MID-AFTERNOON. COULD BE A BRIEF SWITCH TO WESTERLY WINDS FOR AN HOUR OR TWO...THEN SHIFT BACK TO MORE SOUTH-SOUTHWEST. AN UPPER LEVEL SHORTWAVE MOVING IN FROM THE SOUTHWEST WILL WORK ON THE FRONT TO SPAWN SCT SHRA/TS NEAR THE SFC FRONT...AND THIS ACTIVITY COULD IMPACT THE TAF SITES FOR A FEW HOURS THIS AFTERNOON. SKIES SHOULD CLEAR THIS EVENING AS DRY AIR WRAPS INTO THE STORM SYSTEM...PER LATEST SATELLITE IMAGERY. MASS OF MVFR/IFR CIGS ASSOCIATED WITH THE MAIN SFC LOW WITH THE SYSTEM...CURRENTLY ACROSS SD. THE LOW WILL MOVE EAST/NORTHEAST TONIGHT...BRINGING THE CLOUD SHIELD IN NEAR 12Z. NUMERICAL GUIDANCE SUGGEST ONLY VFR CIGS BY THAT TIME...BUT HARD TO ARGUE WITH SFC OBS/SATELLITE...PLUS RH FIELDS SUPPORT LOWER CIGS. WILL BRING IN SOME MVFR CIGS FOR SUN MORNING. ANOTHER FORECAST CONSIDERATION IS THE POTENTIAL FOR FOG...ESPECIALLY IN THE RIVER VALLEYS. WITH EXPECTED CLEARING TONIGHT...THE SFC PRESSURE GRADIENT BECOMING BAGGY - THUS LIGHT WINDS...AND RECENT RAINS TO MOISTEN THE BOUNDARY LAYER...IT COULD BE FAVORABLE FOR SUB 1SM AT KLSE. HOW LONG IT STAYS CLEAR WILL PROBABLY BE THE BIGGEST FACTOR...AND A LOT OF UNCERTAINTY HERE. WILL ADD BCFG FOR NOW. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM....BAUMGARDT HYDROLOGY....BAUMGARDT AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
634 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 523 AM CDT SAT OCT 5 2013 WITH CONVECTION SHIFTING EAST AND LACK OF OVERALL ACTIVITY EXPECTED THROUGH THE NEXT SEVERAL HOURS...HAVE TRENDED THE MORNING MUCH DRIER. ONLY ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE MORNING...RAMPING UP TOWARD AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTI-CELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 634 AM CDT SAT OCT 5 2013 COLD/OCCLUDED FRONT CONTINUED TO WORK ITS WAY INTO AND ACROSS THE FCST AREA EARLY THIS MORNING. AS OF 11Z IT WAS NEAR A KOWA-KAUM-KOLZ LINE. SOUTHWEST OF THIS BOUNDARY CONDITIONS WERE GENERALLY GOOD VFR WITH ONLY ISOLATED -SHRA. NORTHEAST OF THE BOUNDARY...CIGS WERE HIGHLY VARIABLE RANGING FROM LIFR TO VFR. CIGS GENERALLY IMPROVED BEHIND CLUSTERS OF CONVECTION OVERNIGHT...THEN DROPPING BACK DOWN A COUPLE HOURS LATER. FRONT MAKING SLOW PROGRESS AND VARYING TIMING SOLUTIONS AMONG THE MODELS...BUT APPEARS FRONT/BOUNDARY WILL LIFT NORTHEAST OF KRST AROUND 14Z AND KLSE AROUND 19Z. WITH FRONT PAST KRST AROUND 14Z...CONVECTION CHANCES DIMINISH FOR THE DAY AND ONLY CARRIED VCSH IN THE 17-20Z TIME-FRAME. WITH FRONT NEAR KLSE AT MID-DAY AND PEAK HEATING...CONTINUED A -SHRA/VCSH MENTION IN THE MAINLY 19-22Z PERIOD. BOUNDARY CONTINUES LIFTING NORTHEAST LATE THIS AFTERNOON/TONIGHT WITH FALLING DEW POINTS AND A DRIER AIRMASS SPREADING ACROSS THE AREA. TREND FOR ONLY SCT CLOUDS TONIGHT CONTINUES TO LOOK GOOD. GIVEN THE RECENT RAINS...WILL HAVE TO WATCH VALLEY LOCATIONS FOR BR/FG LATE TONIGHT IF SKIES DO END UP MOSTLY CLEAR AND THE VALLEY WINDS DECOUPLE. APPEARS TO BE ENOUGH GRADIENT WINDS LATER TONIGHT AND LEFT ANY BR/FG MENTION AFTER 09Z OUT OF KLSE FOR NOW. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE.......BAUMGARDT SHORT TERM...BAUMGARDT LONG TERM....BAUMGARDT HYDROLOGY....BAUMGARDT AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
525 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 523 AM CDT SAT OCT 5 2013 WITH CONVECTION SHIFTING EAST AND LACK OF OVERALL ACTIVITY EXPECTED THROUGH THE NEXT SEVERAL HOURS...HAVE TRENDED THE MORNING MUCH DRIER. ONLY ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE MORNING...RAMPING UP TOWARD AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTICELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BAUMGARDT LONG TERM...BAUMGARDT AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
414 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTICELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER LARGER SCALE RIDGING AND ABOVE NORMAL TEMPERATURES. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM...BAUMGARDT AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT FRI OCT 4 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT AND THE POSSIBILITY OF A FEW SEVERE STORMS IN CENTRAL WISCONSIN LATE SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON. LATEST SURFACE OBSERVATIONS SHOWED SURFACE LOW PRESSURE OVER CENTRAL NEBRASKA...LIFTING NORTHEAST. A WARM FRONT EXTENDED SOUTHEAST THROUGH SOUTHWEST AND CENTRAL IOWA. THE FRONT WILL LIFT NORTH LATE THIS AFTERNOON INTO THIS EVENING AND BE THE FOCUS FOR STRONG TO SEVERE THUNDERSTORM DEVELOPMENT AS A POTENT UPPER LOW PUSHES EAST ACROSS THE NEBRASKA PANHANDLE. THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO NORTHERN IOWA AND PERHAPS EXTREME SOUTHWEST WISCONSIN THIS EVENING. STRONG 850 MB MOISTURE TRANSPORT FOCUSES INTO THE FRONT THIS EVENING...LEADING TO SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. MEANWHILE THE SURFACE LOW WILL LIFT NORTH INTO SOUTHEAST SOUTH DAKOTA AS THE LOW OCCLUDES. A TRIPLE POINT LIFTS NORTHEAST FROM NORTHEAST IOWA INTO SOUTH CENTRAL MINNESOTA LATE IN THE EVENING. THE 04.17 HRRR SHOWS ISOLATED STRONG STORMS DEVELOPING ALONG THE FRONT. STORMS ALSO DEVELOP OVER WESTERN IOWA EARLY THIS EVENING CLOSER TO THE OCCLUSION. THESE STORMS WILL LIKELY BE SUPERCELLS...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES. THE STORMS FURTHER TO THE NORTH OVER THE FORECAST AREA...SHOULD BE NORTH OF THE WARM FRONT AND ELEVATED IN NATURE. 1-7 KM BULK SHEAR VALUES HOVER RIGHT AROUND 30 KTS DURING THE EVENING HOURS SO CANNOT RULE OUT ISOLATED SEVERE STORMS CAPABLE OF PRODUCING LARGE HAIL...HEAVY RAINFALL...AND POSSIBLY DAMAGING WINDS. THE HIGHEST CHANCES FOR SEVERE WEATHER WILL BE OVER NORTHEAST IOWA AND SOUTHEAST MINNESOTA...WEST OF HIGHWAY 52. A FEW OF THESE STRONGER STORMS COULD MAINTAIN INTENSITY INTO PORTIONS OF WESTERN WISCONSIN BUT SHOULD THEN WEAKEN AS THEY MOVE EAST...BUT STILL CAPABLE OF PRODUCING HEAVY RAINFALL. THE 850 MB MOISTURE TRANSPORT GRADUALLY SHIFTS EAST INTO WESTERN WISCONSIN OVERNIGHT WITH WIDESPREAD SHOWERS AND STORMS PERSISTING. THE MAIN THREAT FROM THE STORMS SHOULD GRADUALLY SHIFT TOWARDS HEAVY RAIN LATE IN THE NIGHT. A COLD FRONT THEN PUSHES EAST ACROSS THE REGION EARLY SATURDAY MORNING AND SHOULD BE POSITIONED RIGHT ALONG THE MISSISSIPPI RIVER BY THE MID TO LATE MORNING HOURS. IF ENOUGH INSTABILITY CAN BUILD AHEAD OF THE FRONT...THERE IS THE POSSIBILITY OF SEEING A FEW STRONG TO SEVERE STORMS OVER CENTRAL WISCONSIN. THE MAIN HAZARDS FROM THESE STORMS WOULD BE DAMAGING WINDS. SHOWERS AND STORMS WILL END FROM WEST TO EAST SATURDAY AFTERNOON AS A DRY SLOT PUSHES INTO THE REGION. TEMPERATURES SHOULD FALL ACROSS THE AREA SATURDAY AFTERNOON IN THE WAKE OF THE COLD FRONT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 MOST OF THE FORECAST AREA WILL REMAIN IN THE DRY SLOT SATURDAY NIGHT...WITH THE EXCEPTION OF NORTH CENTRAL WISCONSIN WHERE A FEW SHOWERS MAY LINGER. PLAN ON A COOLER NIGHT WITH LOWS FALLING INTO THE 40S. A FEW 30S CANNOT BE RULED OUT OVER CENTRAL WISCONSIN. THE UPPER LOW MOVES INTO INTO WESTERN IOWA ON SUNDAY AND EVENTUALLY INTO WESTERN ILLINOIS SUNDAY NIGHT. SHOWERS WRAPPING AROUND THE LOW LOOK TO MOVE INTO THE REGION SUNDAY AND WILL LIKELY CONTINUE INTO SUNDAY NIGHT AS THE LOW PROGRESSES EAST. THE LOW THEN LOOKS TO MOVE INTO THE EASTERN GREAT LAKES LATE ON TUESDAY WITH HIGH PRESSURE BUILDING INTO THE AREA IN ITS WAKE. HIGH PRESSURE THEN BUILDS OVER THE AREA WEDNESDAY INTO THURSDAY WITH DRY AND QUIET WEATHER EXPECTED...OUTSIDE OF THE POSSIBILITY OF OF SOME EARLY MORNING VALLEY FOG. A TROUGH IS EXPECTED TO DIG INTO THE SOUTHWEST CONUS LATE IN THE WEEK. SOUTHWEST FLOW LOOKS TO DEVELOP OVER THE UPPER MISSISSIPPI RIVER VALLEY LATE FRIDAY INTO SATURDAY. FORECAST MODELS SHOWS THE TROUGH EJECTING INTO THE CENTRAL AND NORTHERN PLAINS...WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SYSTEM OVER THE NEXT SEVERAL MODEL RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR WIZ017-029-032>034- 041>044-053. MN...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR IAZ008>011-018-019. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
430 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA TODAY AND TONIGHT...STALLING OFF THE COAST AS COOLER HIGH PRESSURE BUILDS IN FROM THE WEST AND NORTH. AN AREA OF LOW PRESSURE...THE REMNANTS OF KAREN...WILL MOVE UP THE COAST ALONG THE STALLED FRONT TUESDAY AND WEDNESDAY. HIGH PRESSURE WILL GENERALLY PREVAIL THURSDAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... PRE-DAWN...A DEEP MOIST PLUME OFF THE ATLC AND STRONG LOW LEVEL MOISTURE CONVERGENCE CONTINUES TO IGNITE BATCHES OF SHOWERS FROM THE OCEAN...ONSHORE OVER SOUTHERN SOUTH CAROLINA AND THROUGH THE CHARLESTON QUAD-COUNTY. THERE IS 25 KT OF SHEAR IN THE 0-1KM LAYER AND A FEW SHOWERS HAVE PRODUCED SOME BRIEFLY GUSTY WINDS AND EVEN VERY WEAK ROTATION AT TIMES. LATEST RAP SHOWS CONTINUED DESTABILIZATION EARLY THIS MORNING AND INCREASING UPPER DIFLUENCE. WE WILL BE KEEPING AN EYE OUT FOR ISOLATED STRONG CELLS EMBEDDED WITHIN THE MAIN BAND OF CONVERGENCE. IF NOTHING ELSE...WITH PWATS NEAR 1.9 INCHES...BRIEF TORRENTIAL DOWNPOURS ARE LIKELY WITH ACTIVITY THAT STREAMS ONSHORE. THIS COULD SPELL LOCALIZED MINOR FLOODING ISSUES WITH SOME PONDING WATER IN SPOTS ACROSS PARTS OF CHARLESTON AND BERKELEY COUNTIES AT TIMES. AN EXTREMELY COMPLEX SYNOPTIC SCENE TODAY WITH A PLETHORA OF PLAYERS OF INTEREST. BANDS OF DEEP TROPICAL MOISTURE ADVECTING IN FROM BOTH THE ATLC AND THE GULF OF MEXICO...GULF MOISTURE RESIDUAL FROM REMNANTS OF KAREN. LIKELY TO CATEGORICAL POPS IN ORDER TODAY WITH GEORGIA AREAS THE MOST DIFFICULT TO PIN DOWN. IN SE GEORGIA...THE DEEP MOISTURE WILL ARRIVE DURING THE DAY BUT MAINLY MISSING OUT ON A GOOD BIT OF THE UPPER FORCING THIS MORNING THAT IS SHIFTING THROUGH THE CSRA-MIDLANDS-PEE REGIONS OF GA/SC. THIS AFTERNOON THAT REGION WILL BE BETWEEN MID LEVEL DISTURBANCES WITH MARGINAL INSTABILITY AND NOT MUCH LOW LEVEL CONVERGENCE. THE PWATS ARE SO ANONYMOUSLY HIGH HOWEVER...WE DID NOT DO TOO MUCH RE-ARRANGEMENT OF OUR POP SCHEME. IN SE SOUTH CAROLINA...CLOSER TO THE CHARLESTON AREA...IT LOOKS LIKE A WET AND UNSETTLED A DAY. DEEP LAYERED SHEAR GENERALLY DECREASES DURING THE DAY BIT THROUGH EARLY AFTERNOON...WE CANNOT RULE OUT AN ISOLATED STRONG TO SEVERE TSTM BUT MOISTURE PROFILES AND FORECAST SOUNDINGS SUGGEST THE 5 PERCENT RISK FROM THE STORM PREDICTION CENTER IS ON TRACK FOR THE FIRST HALF OF TODAY UNTIL THE LOW LEVEL JET PULLS OUT. CONVECTIVE ELEMENTS ALREADY HAVE PRODUCED TORRENTIAL DOWNPOURS EAST OF I-95 IN SOUTH CAROLINA AND SUSPECT THIS WILL REMAIN THE CASE AHEAD OF THE COLD FRONT TODAY. TONIGHT THE COLD FRONT BEGINS TO BACKDOOR S THROUGH THE REGION TONIGHT AS SURFACE HIGH PRES BUILDS INTO THE MID ATLC REGION WHILE LOW PRES SETTLES IN OVER N FLORIDA. GOOD UPPER FORCING FOR ASCENT IS PROGGED TO DEVELOP OVER THE REGION FROM S TO N OVERNIGHT AS THE BASE OF THE SOUTHERN LATITUDE TROUGH MOVES THROUGH S GEORGIA AND N FLORIDA. AN EXCELLENT SETUP FOR THE START OF SOME SOAKING RAINFALL AT TIMES WHICH WILL BE IN THE FORECAST INTO MID WEEK. WE RAISED LATE NIGHT POPS IN SE GEORGIA TO CATEGORICAL ON THIS PACKAGE. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... THE MODEL SUITE HAS CHANGED DRASTICALLY FROM WHAT WE WERE ANALYZING 24 HOURS PRIOR. A STRONGER THAN PREVIOUSLY EXPECTED SOUTHERN STREAM VORT IS TRACKING ALONG THE WESTERN GULF COAST. THIS FEATURE WILL INTERACT WITH THE RESIDUAL LOW FROM KAREN AS IT CROSSES FLORIDA. MEANWHILE A LARGE AREA OF HIGH PRESSURE WILL OVERSPREAD THE EASTERN UNITED STATES TUESDAY. AS THE REMNANT SURFACE LOW MOVES INTO THE SOUTHWEST ATLANTIC AHEAD OF THE UPPER VORT...IT WILL DEEPEN AS IT LIFTS SLOWLY NORTHEAST. A COLD AIR DAMMING REGIME WILL DEVELOP AND PERSIST FROM TUESDAY THROUGH THURSDAY AS THE OFFSHORE LOW STRENGTHENS COLD AIR ADVECTION ACROSS INLAND AREAS. CONDITIONS LOOK RIPE FOR WIDESPREAD PRECIPITATION ON TUESDAY...ESPECIALLY SOUTHERN SC. THE NAM SHOWS AN IMPRESSIVE COUPLED UPPER JET OVER THE REGION AT 18Z TUESDAY...PRODUCING STRONG UPPER DIVERGENCE. FAIRLY DEEP MOISTURE WILL STREAM IN OFF THE ATLANTIC ATOP THE COOL SURFACE WEDGE WITH PWATS AROUND 2 INCHES. STRONG LIFT WILL DEVELOP OVERHEAD TUESDAY...WITH THE BEST LIFT SHIFTING NORTHEAST OF THE AREA TUESDAY NIGHT. WE INCREASED POPS TO CATEGORICAL ACROSS SOUTHERN SC ON TUESDAY WITH LIKELY POPS ELSEWHERE AND THROUGH TUESDAY NIGHT. TEMPERATURES ON TUESDAY WILL BE A REAL SHOCK COMPARED TO TODAY. OVERCAST SKIES...STRONG COLD ADVECTION AND EXTENSIVE PRECIP WILL LIMIT HIGH TEMPS TO THE MID/UPPER 60S EXCEPT FOR A FEW 70S CLOSER TO THE COAST. THE SURFACE LOW WILL VERY SLOWLY LIFT NORTHEAST JUST OFF THE COAST WEDNESDAY AND WEDNESDAY NIGHT. THOUGH THE BEST LIFT WILL SHIFT NORTHEAST OF THE LOCAL FORECAST AREA...ENOUGH RESIDUAL MOISTURE AND OVERRUNNING WILL MAINTAIN OVERCAST SKIES AND SCATTERED RAIN SHOWERS ON WEDNESDAY. HIGH TEMPS WILL AGAIN BE WELL BELOW NORMAL DUE TO THE AFOREMENTIONED LIMITING FACTORS. WE ARE SHOWING UPPER 60S TO LOWER 70S. THE MOISTURE AND LIFT ASSOCIATED WITH THE COASTAL LOW WILL SHIFT NORTHEAST OF THE AREA ON THURSDAY AS THE UPPER LOW ALSO LIFTS NORTHEAST. CLOUDS WILL SLOWLY CLEAR OUT FROM THE SOUTHWEST AND RAIN CHANCES WILL BE MINIMAL. TEMPERATURES SHOULD MAKE IT INTO THE MIDDLE 70S BY AFTERNOON. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... BROAD HIGH PRESSURE WILL PREVAIL DURING THE EXTENDED WITH GENERALLY DRY WEATHER AND SEASONABLE TEMPERATURES IN THE 50S AT NIGHT AND 70S DURING THE DAY. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... KCHS...SHOWERS AND MVFR CIGS ARE EXPECTED TO IMPACT THE TERMINAL OCCASIONALLY THROUGH THE MORNING HOURS. SMALL CHANCES FOR IFR CONDITIONS...THEY LIKELY WOULD BE VERY BRIEF AND NO FOG CONCERNS. LOW CONFIDENCE ON TIMING CHANCES FOR RAIN LATER TODAY WITH A COMPLEX SYNOPTIC SETUP AND A SEEMINGLY EXCELLENT COMBO OF DEEP MOISTURE AND UPPER DYNAMICS. OUTSIDE OF SHOWER AREAS...WE ARE MOST LIKELY TO BE VFR THROUGH 06Z TUE. KSAV...LOW CONFIDENCE WITH REGARDS TO FORECASTING THE ELEMENTS THROUGH THIS EVENING GIVEN THE TERMINALS PROXIMITY TO SEVERAL DEEP MOISTURE SOURCES AND MODEL DISCREPANCIES WITH REGARD TO COVERAGE AND TIMING OF RAIN. WE MAINTAINED PERSISTENCE WITH THE PREVIOUS TAF INDICATING THE BEST CHANCES OF RAIN FROM LATE MORNING THROUGH MID AFTERNOON BUT IT COULD BE LATER OR LESS THAN PROJECTED. CIGS WILL MAINLY BE VFR OVERNIGHT BUT LATE NIGHT THROUGH MID MORNING THERE IS A CHANCE FOR MVFR/IFR CIGS TO STREAM THROUGH BUT NO FOG CONCERNS. EXTENDED AVIATION OUTLOOK...A PROLONGED PERIOD OF MVFR/IFR CEILINGS IS EXPECTED FROM LATE TONIGHT THROUGH THURSDAY NIGHT. PREVAILING MVFR CEILINGS LIKELY DURING DAYTIME HOURS WITH A DROP TO IFR EACH OVERNIGHT PERIOD. VSBYS MAY BE OCCASIONALLY REDUCED IN RAIN TUESDAY THROUGH WEDNESDAY. && .MARINE... A SSE FLOW 15 KT TO OCCASIONALLY 15-20 KT AT TIMES HAS RAISED SEAS TO 6 FT OUT AT BUOY 41004 BUT MAINLY 3 TO 5 FT WITHIN 20 NM OF THE COAST...HIGHEST OFF OF CHARLESTON COUNTY. THE LOW LEVEL JET AHEAD OF THE COLD FRONT WILL WEAKEN TODAY AS THE LOW LEVEL FRONTAL TROUGH APPROACHES. WINDS WILL BECOMES LIGHTER THIS AFTERNOON AND EVENING AND EVEN VARIABLE AT TIMES. SEAS WILL ALSO DIMINISH A BIT. LATER TONIGHT...CHANGES IN THE OFFING AS N TO NE SURGING BEGINS TO INCREASE TOWARD DAYBREAK TUESDAY IN THE WAKE OF THE COLD FRONT. THE LATE NIGHT SURGE WILL BE MOST NOTICEABLE OFF OF THE CENTRAL SOUTH CAROLINA COAST AND LIKELY REACH 15 KT BY DAWN. SEAS TONIGHT 2 TO 4 FT. WINDS WILL CRANK UP FROM THE NNE TUESDAY IN RESPONSE TO THE COASTAL LOW MOVING INTO THE SOUTHWEST ATLANTIC FROM THE GULF. THE GRADIENT WILL BECOME PINCHED BETWEEN INLAND HIGH PRESSURE AND COASTAL LOW PRESSURE...PRODUCING A PROLONGED STRETCH OF ENHANCED NNE WINDS. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY DEVELOP DURING THE DAY TUESDAY WITH MARGINAL ADVISORY CONDITIONS CONTINUING INTO WEDNESDAY OR LATER. SEAS WILL NOT BUILD SUBSTANTIALLY DUE TO THE OFFSHORE FETCH BUT SOME 6 FOOTERS ARE POSSIBLE AT TIMES MAINLY BEYOND 20 NM FROM SHORE. WINDS WILL CONTINUE OUT OF THE N/NNE INTO THE WEEKEND BUT SPEEDS WILL DROP OFF CONSIDERABLY BY THURSDAY AS THE SURFACE LOW LIFTS NORTHEAST AND THE GRADIENT WEAKENS. RIP CURRENTS...AFTER A COLD FRONT ADVANCES THROUGH THE REGION... SUSTAINED NNE WINDS COULD CONTRIBUTE TO AN ELEVATED RIP CURRENT RISK ON AREA BEACHES TUESDAY THROUGH THURSDAY. && .TIDES/COASTAL FLOODING... BEGINNING TUESDAY...ASTRONOMICAL HIGH TIDES COULD COMBINE WITH PERSISTENT/ELEVATED NORTHEAST WINDS TO PRODUCE MINOR SALTWATER INUNDATION IN LOW-LYING AREAS NEAR THE COAST AROUND THE TIMES OF THE LATE MORNING/EARLY AFTERNOON HIGH TIDES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...JRL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
145 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA MONDAY AND WILL PUSH THROUGH THE REGION MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL LOW PRESSURE IS THEN EXPECTED TO SLOWLY TRACK NORTHEAST OVER THE REGION THROUGH MIDWEEK. HIGH PRESSURE WILL EXPAND INTO THE REGION AND WILL PREVAIL THROUGH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... A DEEP MOIST PLUME OFF THE ATLC AND STRONG LOW LEVEL MOISTURE CONVERGENCE CONTINUES TO IGNITE BATCHES OF SHOWERS FROM THE OCEAN...ONSHORE OVER SOUTHERN SOUTH CAROLINA AND THROUGH THE CHARLESTON QUAD-COUNTY. THERE IS ABOUT 20 KT OF SHEAR IN THE 0-1KM LAYER AND A FEW SHOWERS HAVE PRODUCED SOME BRIEFLY GUSTY WINDS AND EVEN VERY WEAK ROTATION OFFSHORE. LATEST RAP SHOWS CONTINUED DESTABILIZATION OVERNIGHT AND INCREASING UPPER DIFLUENCE. WILL BE KEEPING AN EYE OUT FOR ISOLATED STRONG CELLS EMBEDDED WITHIN THE MAIN BAND OF CONVERGENCE. IF NOTHING ELSE...WITH PWATS NEAR 1.9 INCHES...BRIEF TORRENTIAL DOWNPOURS ARE LIKELY WITH ACTIVITY THAT STREAMS ONSHORE. THIS COULD SPELL MINOR FLOODING ISSUES WITH SOME PONDING WATER IN SPOTS ACROSS PARTS OF CHARLESTON AND BERKELEY COUNTIES AT TIMES. WE LOWERED POPS A BIT IN THE OVERNIGHT TO THE W OF I-95 AS LATEST MODELS SHOW A VOID AREA BETWEEN THE CONVECTION OVER N GEORGIA AND THE SOUTH CAROLINA UPSTATE AND THE MASS OF CONVECTION ASSOCIATED WITH THE EX-TROPICAL LOW IN THE NE GULF OF MEXICO. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... AHEAD OF AN APPROACHING COLD FRONT...AN AXIS OF DEEP LAYER MOISTURE AND FORCING FOR ASCENT SUPPORTED IN PART BY UPPER JET DIVERGENCE WILL ALREADY BE ADVANCING IN TO THE FORECAST AREA MONDAY MORNING AND WILL GRADUALLY ADVANCE THROUGH THE REGION DURING THE DAY. THIS SCENARIO WILL SUPPORT MOST/ALL LOCATIONS SHOULD RECEIVE MEASURABLE RAINFALL. 12Z GUIDANCE CONTINUES TO JUSTIFY ONGOING CATEGORICAL POPS. PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY RAINFALL. ALSO...CANNOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM WITH DAMAGING WET MICROBURSTS. HOWEVER...CLOUD COVER/PRECIPITATION WILL LIMIT WARMING/DESTABILIZATION...AND THE AXIS OF STRONGEST WIND SHEAR WILL REMAIN WELL NORTH OF THE REGION...SO THE POTENTIAL FOR SEVERE WEATHER APPEARS QUITE LOW. BY MONDAY EVENING...THE AXIS OF DEEPEST MOISTURE WILL SHIFT INTO COASTAL COUNTIES AN/OR ADJACENT COASTAL WATERS...AND THE SURFACE COLD FRONT WILL PRESS THROUGH THE FORECAST AREA FROM NORTH TO SOUTH OVERNIGHT INTO TUESDAY MORNING. MEANWHILE...A SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY ADVANCING THROUGH EAST TX WILL DIG INTO THE NORTHERN GULF OF MEXICO THEN WILL SWING TOWARD THE SOUTHEAST COAST MONDAY NIGHT THROUGH TUESDAY. IN RESPONSE TO FORCING FOR ASCENT IN ADVANCE OF THIS FEATURE...THE POST FROPA DRYING TREND WILL CEASE AND DEEP LAYER MOISTURE WILL LIKELY EXPAND TOWARD THE N/W INTO THE FORECAST AREA. AS A RESULT...BUMPED MONDAY NIGHT POPS UP A BIT FROM THE PREVIOUS FORECAST...THEN RAISED POPS SIGNIFICANTLY ACROSS THE FORECAST AREA TUESDAY. AS OF THE SUNDAY AFTERNOON FORECAST PACKAGE...CAPPED MAX POPS AT HIGH CHANCE TUESDAY...BUT HIGHER POPS COULD EVENTUALLY BE REQUIRED. MEANWHILE...A WEDGE OF COOL/MOIST ARE WILL OVERSPREAD THE FORECAST AREA TUESDAY...AND TEMPERATURES WILL LIKELY NOT RECOVER BEYOND THE LOWER TO MID 70S MOST AREAS. IN FACT...IF/WHERE PRECIPITATION BECOMES MORE WIDESPREAD THAN CURRENTLY FORECAST...TEMPERATURES COULD REMAIN IN THE 60S ACROSS SOME N/W COUNTIES. THE UPPER LOW IS PROGGED TO ONLY SLOWLY ROLL NE ALONG THE SE COAST TUESDAY NIGHT THROUGH WEDNESDAY...THUS AT LEAST SLIGHT CHANCE/CHANCE POPS ARE JUSTIFIED THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DEEP LAYERED RIDGING WILL DOMINATE THE PATTERN IN THE EXTENDED RANGE. REINFORCING CANADIAN HIGH PRESSURE WILL MAINTAIN BELOW NORMAL TEMPS WITH LOWS IN THE MID/UPPER 50S AND HIGHS IN THE UPPER 70S WITH MAINLY DRY CONDITIONS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... KCHS...SHOWERS AND MVFR CIGS ARE EXPECTED TO IMPACT THE TERMINAL OCCASIONALLY THROUGH THE MORNING HOURS. SMALL CHANCES FOR IFR CONDITIONS...THEY LIKELY WOULD BE VERY BRIEF AND NO FOG CONCERNS. LOW CONFIDENCE ON TIMING CHANCES FOR RAIN LATER TODAY WITH A COMPLEX SYNOPTIC SETUP AND A SEEMINGLY EXCELLENT COMBO OF DEEP MOISTURE AND UPPER DYNAMICS. OUTSIDE OF SHOWER AREAS...WE ARE MOST LIKELY TO BE VFR THROUGH 06Z TUE. KSAV...LOW CONFIDENCE WITH REGARDS TO FORECASTING THE ELEMENTS THROUGH THIS EVENING GIVEN THE TERMINALS PROXIMITY TO SEVERAL DEEP MOISTURE SOURCES AND MODEL DISCREPANCIES WITH REGARD TO COVERAGE AND TIMING OF RAIN. WE MAINTAINED PERSISTENCE WITH THE PREVIOUS TAF INDICATING THE BEST CHANCES OF RAIN FROM LATE MORNING THROUGH MID AFTERNOON BUT IT COULD BE LATER OR LESS THAN PROJECTED. CIGS WILL MAINLY BE VFR OVERNIGHT BUT LATE NIGHT THROUGH MID MORNING THERE IS A CHANCE FOR MVFR/IFR CIGS TO STREAM THROUGH BUT NO FOG CONCERNS. EXTENDED AVIATION OUTLOOK...OCCASIONAL FLIGHT RESTRICTIONS ARE EXPECTED MONDAY AFTERNOON/NIGHT DUE TO MOISTURE/SHOWERS ALONG A COLD FRONT. THE PROBABILITY FOR FLIGHT RESTRICTIONS...MAINLY IN LOW CEILINGS...HAS INCREASED IN THE WAKE OF COLD FROPA TUESDAY INTO WEDNESDAY. && .MARINE... OVERNIGHT...CONDITIONS ACROSS THE LOCAL WATERS WILL STEADILY WORSEN AS WINDS/SEAS INCREASE. AS THE APPROACHING COLD FRONT DRAWS CLOSER...THE PRESSURE GRADIENT WILL TIGHTEN AND RESULT IN STRENGTHENING SOUTHERLY FLOW. 15-20 KT WINDS WILL BE WIDESPREAD AND SHOULD REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THANKS TO THE WARM ADVECTION REGIME LIMITING GUST POTENTIAL. SEAS WILL CORRESPONDINGLY RISE AS WELL BY LATE TONIGHT...BECOMING 3-5 FT WITHIN 20 NM AND A SOLID 5 FT BEYOND. AHEAD OF AN APPROACHING COLD FRONT...EXPECT ELEVATED SOUTHERLY WINDS/SEAS MONDAY. 06/12Z GUIDANCE SUGGESTS THAT WINDS CAPPED AT 20 KT AND SEAS CAPPED AT 5 FT...JUST BELOW SMALL CRAFT ADVISORY LEVELS...WILL SUFFICE. WITHIN THE FRONTAL TROUGH MONDAY NIGHT...A WEAK PRESSURE GRADIENT AND LIGHT/VARIABLE WINDS COULD PREVAIL FOR SEVERAL HOURS. THEN...A STRONG COLD FRONT WILL PUSH THROUGH THE WATERS FROM NORTH TO SOUTH LATE MONDAY NIGHT INTO TUESDAY. IN THE WAKE OF COLD FROPA...NORTH/NORTHEAST WINDS WILL SURGE INTO THE WATERS. 06/12Z GUIDANCE STRONGLY SUGGESTS THAT THE TIGHTENING SURFACE PRESSURE GRADIENT AND DEEPENING MARINE LAYER MIXING PRODUCED BY COLD AIR ADVECTION WILL SUPPORT SMALL CRAFT ADVISORY WINDS/SEAS MOST AREAS TUESDAY INTO WEDNESDAY AND PERHAPS INTO LATE WEEK AS ELEVATED SEAS PERSIST BEYOND 20 NM. IN FACT...THERE IS A LOW PROBABILITY FOR THE GRADIENT TO TIGHTEN SUFFICIENTLY BETWEEN LOW PRESSURE SOUTH/SOUTHEAST OF THE WATERS AND HIGH PRESSURE TO THE NORTH TO SUPPORT GALE FORCE GUSTS ESPECIALLY OVER GA WATERS TUESDAY/TUESDAY NIGHT. RIP CURRENTS...AFTER A COLD FRONT ADVANCES THROUGH THE REGION...SUSTAINED NE WINDS COULD CONTRIBUTE TO AN ELEVATED RIP CURRENT RISK ON AREA BEACHES TUESDAY THROUGH LATE WEEK. && .TIDES/COASTAL FLOODING... BEGINNING TUESDAY...ASTRONOMICAL HIGH TIDES COULD COMBINE WITH PERSISTENT/ELEVATED NORTHEAST WINDS TO PRODUCE MINOR SALTWATER INUNDATION IN LOW-LYING AREAS NEAR THE COAST AROUND THE TIMES OF THE LATE MORNING/EARLY AFTERNOON HIGH TIDES THIS WEEK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...SPR LONG TERM...JRL AVIATION... MARINE.... TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
125 AM EDT MON OCT 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE WRN CONUS AND A TROUGH FROM HUDSON BAY INTO NRN ONTARIO. THE PERSISTENT MID/UPPER LEVEL LOW HAD EDGED EASTWARD INTO ERN IA. AT THE SFC...LOW PRES WAS LOCATED OVER S CNTRL LAKE SUPERIOR WITH A COLD FRONT INTO CNTRL LOWER MI AND A TROUGH TO THE SW INTO SE MN. RAIN ASSOCIATED WITH A WEAK SHORTWAVE IN THE WARM CONVEYOR AHEAD OF THE COLD FRONT WAS LIFTING NNE THROUGH ERN CWA. OTHERWISE...RADAR INDICATED ONLY VERY WEAK RETURNS OVER THE WEST WITH SOME SPRINKLES OR DRIZZLE. FARTHER WEST...A NARROW BAND OF RAIN TO NEAR DLH WAS ASSOCIATED WITH THE MID LEVEL DEFORMATION/FGEN BAND/TROWAL ON THE NRN FLANK OF THE MID LEVEL LOW. VIS LOOP SHOWED CLEARING OVER SRN UPPER MI WITH THE ADVANCING DRY SLOT. TONIGHT...MODELS SUGGEST THAT THE NE MN RAIN BAND WILL CONTINUE TO SLOWLY SPREAD INTO WEST UPPER MI THIS EVENING AND GRADUALLY SHRINK OVERNIGHT...PER FCST 310KE SURFACE. THERE MAY ALSO BE A FEW LIGHT SHOWERS THROUGH CNTRL UPPER MI THIS EVENING AS THE DRY SLOT AREA GIVES WAY TO INCREASING CLOUDS WITH INCREASING 700-300 MB QVECTOR CONV AND LOW LEVEL CONV NEAR THE TROUGH. IN ADDITION...SOME LAKE ENHANCED SHOWERS MAY DEVELOP OVERNIGHT AS 850 MB TEMPS DROP TO AROUND 1C WITH NNW LOW CYCLONIC FLOW INCREASING. SO...CHANCE POPS WERE MAINTAINED OVER MOST OF THE CWA TONIGHT EVEN IF ONLY INTERMITTENT PERIODS OF RAIN DEVELOP. MONDAY...THE REMAINING SYNOPTIC AND LAKE ENHANCED PCPN OVER THE EAST IS EXPECTED TO DIMINISH DURING THE MORNING AS THE MID LEVEL QVECTOR CONV FORCING AND DEEPER MOISTURE DEPART TO THE EAST. OTHERWISE...GRADUAL CLEARING AND SOME SUNSHINE DURING THE AFTERNOON WILL BRING TEMPS AGAIN TO NEAR SEASONAL NORMALS IN THE UPPER 50S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 QUIETER WEATHER WILL REPLACE THE UNSETTLED ACTIVITY OF THIS PAST WEEK STARTING MONDAY NIGHT. A 500MB RIDGE BUILDS ACROSS THE NORTHERN PLAINS BY 00Z TUESDAY...AND CONTINUES EASTWARD THROUGHOUT THE FORECAST PERIOD. SURFACE HIGH PRESSURE EXPANDS INTO THE GREAT LAKES DURING THE DAY TUESDAY...AND GRADUALLY CENTERS ITSELF OVER THE LOWER LAKES THROUGH FRIDAY AFTERNOON. THE ECMWF/GFS HAVE 925 MB TEMPS UP TO 14-15C FOR WEDNESDAY-FRIDAY AFTERNOON OUT WEST...WHICH PUTS HIGHS ROUGHLY IN THE UPPER 60S/NEAR 70. FOR THE REST OF THE AREA...EXPECT LOW TO MID 60S. BUMPED UP WINDS FOR TUESDAY AND WEDNESDAY TO ACCOUNT FOR TIGHTENING PRESSURE GRADIENT ACROSS UPPER MICHIGAN ASSOCIATED WITH THE SURFACE LOW MOVING JUST NORTH OF LAKE SUPERIOR AND HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES. THOUGH SOUTHERLY WINDS MAY GUST UP TO 20 KTS AND TEMPS WILL BE CLOSE TO 70...AFTERNOON RH WILL BE IN THE 35-40 PERCENT RANGE SO DO NOT EXPECT ANY FIRE WX CONCERNS. FRIDAY NIGHT INTO SUNDAY...A NEGATIVELY TILTED 500MB TROUGH/POSSIBLE CUT OFF LOW WILL DIVE INTO THE PLAINS. THIS WILL PROVIDE THE NEXT CHANCES FOR PRECIPITATION ACROSS UPPER MICHIGAN. RECENT MODEL RUNS HAVE THE SFC LOW PRESSURE SYSTEM MOVING NORTHEAST INTO HUDSON BAY BY SUNDAY MORNING...BRINGING A COLD FRONT ACROSS UPPER MI. BOTH THE GFS/ECMWF HAVE THIS...THOUGH THERE ARE DIFFERENCES IN TIMING...WITH THE GFS BRINGING THE FRONT THROUGH FRIDAY NIGHT AND THE ECMWF BRINGING IT THROUGH SATURDAY AFTERNOON. EVEN MORE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF SHOW UP ON SUNDAY AS ANOTHER TROUGH APPROACHES FROM THE WEST. THE GFS BRINGS SATURDAYS FRONT OUT OF UPPER MICHIGAN BY 12Z SUNDAY...AND THE DRY SLOT MOVES IN OVERHEAD WHICH ENDS PRECIPITATION. BY 00Z MONDAY IT HAS A SHORTWAVE SLIDING INTO THE DAKOTAS AND PRECIPITATION MOVING INTO WESTERN LAKE SUPERIOR OUT AHEAD OF IT. THE ECMWF KEEPS A STRONGER RIDGE OVER THE LOWER LAKES AND NEW ENGLAND STATES FOR SATURDAY AND SUNDAY...SO THE PROGRESSION OF THE FRONT ON SATURDAY IS SLOWER THAN THE GFS...AND IT STALLS OUT OVER CENTRAL/EASTERN UPPER MICHIGAN FOR SUNDAY. OVERALL...GENERAL CHANCE-SLIGHT CHANCE POPS ARE IN THE FORECAST FOR THESE DAYS. IT SEEMS BOTH MODELS HAVE BEEN FAIRLY INCONSISTENT FROM RUN TO RUN ON THE WEEKEND SOLUTION...SO WILL NOT GET CUTE WITH TIMING UNTIL THINGS IRON THEMSELVES OUT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 125 AM EDT MON OCT 7 2013 WITH LOW PRES CONTINUING TO EXIT TO THE E OF LAKE SUPERIOR...DRIER AIR/CLEARING IS MAKING STEADY PROGRESS ACROSS WRN LAKE SUPERIOR PER SATELLITE IMAGERY. KIWD SHOULD REMAIN VFR FOR THE REMAINDER OF THE NIGHT. AT KCMX...STRATOCU SHOULD SCATTER OUT...RESULTING IN MVFR CONDITIONS BECOMING VFR OVER THE NEXT FEW HRS. MVFR CIGS WILL LIKELY RETURN AT KIWD/KCMX FOR A TIME THIS MORNING INTO EARLY AFTN AS DAYTIME HEATING GENERATES STRATOCU. CONDITIONS WILL THEN BECOME VFR IN THE EARLY/MID AFTN AS DRIER AIR ARRIVES. AT KSAW...DRIER AIR WILL BE SLOWER TO ARRIVE AND MAY RESULT IN MVFR CIGS LINGERING THRU EARLY AFTN. VFR CONDITIONS WILL THEN PREVAIL THRU THE REMAINDER OF THE FCST PERIOD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 409 PM EDT SUN OCT 6 2013 NNW WINDS AT 20 TO 30 KNOTS ARE EXPECTED TO DEVELOP LATE TONIGHT INTO MONDAY AS THE LOW PRES TROUGH OVER THE UPPER LAKES MOVES OFF TO THE EAST AND THE GRADIENT TIGHTENS ACROSS THE AREA. A HIGH PRESSURE RIDGE WILL THEN BUILD EAST INTO THE UPPER GREAT LAKES FOR MONDAY NIGHT WITH WINDS DROPPING BELOW 25KTS. AT THIS HIGH SHIFTS EAST ON WEDNESDAY...SOUTHERLY FLOW WILL DEVELOP OVER THE UPPER GREAT LAKES AS A LOW PRESSURE SYSTEM MOVES THROUGH CENTRAL CANADA. AT THIS TIME...THE SOUTHERLY FLOW LOOKS TO STAY BELOW 25KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MCD AVIATION...ROLFSON MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1232 AM CDT MON OCT 7 2013 .UPDATE... ISSUED AT 1017 PM CDT SUN OCT 6 2013 SOME PATCHY RADIATIONAL FOG HAS DEVELOPED OVER THE ARROWHEAD OF MINNESOTA. DEWPOINT DEPRESSIONS AROUND SUNSET WERE LESS THAN 10 DEGREES FOR MOST OF THE FORECAST AREA...EXCEPT FOR THE FAR NORTHWEST COUNTIES. THEN...AS OF 9PM SOME DRIER AIR HAD FILTERED IN FROM THE NORTHWEST AND THE BETTER DEWPOINT DEPRESSIONS REMAIN IN THE SAME AREAS. HAVE PUT IN PATCHY TO AREAS OF FOG INTO THE GRIDS FOR THE REST OF THE NIGHT FOR A FAIRLY LARGE PORTION OF THE FORECAST AREA...AND AM ALSO IN THE PROCESS OF UPDATING TERMINAL FORECASTS AS WELL. UPDATE ISSUED AT 641 PM CDT SUN OCT 6 2013 SOME MINOR ADJUSMENTS TO EVENING FORECAST...MAINLY FOR CLOUD TRENDS AND TEMPERATURES FOR THE NEXT FEW HOURS. HAVE SOME CONCERNS FOR THE RECENT RAINFALL SETTING UP GOOD PRECONDITIONS FOR FOG...WITH PLENTY OF LOW LEVEL MOISTURE AND LIGHT NORTHWEST WINDS. CURRENTLY GUIDANCE INDICATES NO FOG IS LIKELY TO FORM. EXPERIENCE BEGS TO DIFFER. FOR NOW WILL MONITOR LOW LEVEL MOISTURE PARAMETERS AND WINDS...AND RE-EVALUATE HERE BEFORE 10 PM. ALSO UPDATED AVIATION SECTION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 MID LEVEL DEFORMATION ZONE EVIDENT ON SATELLITE AND RADAR ACROSS THE CWA. A LINE OF LIGHT RAIN/DRIZZLE EXTENDED FROM THE ARROWHEAD THROUGH AITKIN INTO SOUTHWEST MINNESOTA. THE HRRR HAS BEEN SHOWING THIS BAND DEVELOPING TODAY...BUT WAS A BIT TOO STRONG AND SLOW WITH IT. WE HAVE CHANCE FOR RAIN OVER OUR FAR EASTERN MN CWA AND NORTHWEST WISCONSIN THIS EVENING...AND DIMINISH OVERNIGHT. ANY RAINFALL SHOULD BE RATHER LIGHT...FROM A TRACE TO A COUPLE HUNDREDTHS OF AN INCH. CLEARING WAS ALSO WORKING INTO OUR WESTERN CWA...AND THAT SHOULD CONTINUE AS WELL THROUGH THE NIGHT. WE DO DECREASE SKY COVER TO CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH LOWS IN THE MID THIRTIES TO AROUND FORTY. WE DO NOT EXPECT WINDS TO DECOUPLE OVER A LARGE AREA...BUT A FEW FAVORED LOCATIONS LIKELY WILL SUCH AS KHIB/KBFW AND WE LOWERED TEMPS A BIT MORE THERE. SURFACE HIGH PRESSURE WILL LEAD TO PARTLY TO MOSTLY SUNNY SKIES MONDAY WITH TEMPERATURES WARMING INTO THE UPPER FIFTIES TO LOWER SIXTIES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 THE WESTERN GREAT LAKES REGION WILL BE SITUATED BETWEEN THE DEPARTING RIDGE AND AN APPROACHING NEGATIVELY TILTED LONG WAVE TROUGH THROUGH THE TUESDAY-FRIDAY TIME FRAME. THIS WILL RESULT IN AN INCREASING SW FLOW WITH A RETURN TO UNSEASONABLY WARM H92-H85 TEMPS BY MID WEEK. HAVE INCREASED THE SOUTH WINDS TUESDAY AS LATEST MODEL RUNS ARE IN GOOD AGREEMENT THAT A 40-50 KT LLJ PUSHES OVER MINNESOTA THROUGH TUESDAY AFTERNOON. LATEST NAM BUFR SOUNDINGS AT LOCATIONS ACROSS THE DLH CWA SHOW WINDS AROUND 35 KT IN THE MIX LAYER TUESDAY AFTERNOON AS TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 60 TO LOW 70S. HOWEVER...HIGHER GUSTS TO 40 KT ARE NOT OUT OF THE QUESTION IF TEMPERATURES WARM JUST A FEW DEGREES HIGHER ALLOWING FOR DEEPER MIXING. RAIN CHANCES RETURN TO THE FCST FRIDAY NIGHT/SATURDAY AS A STRONG VORT MAX /WITH CLOSED H85-H50 LOW/ ROUNDS THE BASE OF THE LONG WAVE TROUGH AND LIFTS INTO THE UPPER MIDWEST. THIS LOW WILL BRING CLOUDS AND ONGOING RAIN CHANCES TO THE NORTHLAND THROUGH MUCH OF THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1232 AM CDT MON OCT 7 2013 A FEW TERMINALS HAVE DEVELOPED SOME FOG THIS EVENING WITH LIGHT WINDS...RECENT RAINFALL BOOSTING LOW LEVEL MOISTURE AND RISING PRESSURES. EXPECT FOG TO EVENTUALLY AFFECT ALL 5 TERMINALS. KHYR...KHIB ARE LIKELY TO HAVE THE WORST CONDITIONS WITH LIFR VSBYS AND CIGS FOR AT LEAST A FEW HOURS. BETTER CONDITIONS ELSEWHERE...BUT AT LEAST A SHORT PERIOD OF IFR VSBYS ARE POSSIBLE. ONCE FOG CLEARS BY 15Z MONDAY MORNING...EXPECT VFR CONDITIONS FOR THE REST OF THE TAF PERIOD WITH LIGHT NORTHWEST WINDS TURNING SOUTH AFTER 00Z...STILL LESS THAN 8KTS. && .PRELIMINARY POINT TEMPS/POPS... DLH 42 67 48 66 / 0 0 0 0 INL 41 69 46 67 / 0 0 10 10 BRD 44 72 50 70 / 0 0 0 0 HYR 39 70 48 70 / 0 0 0 0 ASX 43 70 50 69 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...LE SHORT TERM...MELDE LONG TERM...GRANING AVIATION...LE
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1104 PM MDT Sun Oct 6 2013 ...UPDATE TO AVIATION... FOR THE 06Z TAF. VFR conditions will prevail at all terminals through the effective period. Gusts have subsided for now but will begin to increase again late Monday morning. Gusts will once again be strongest over north-central MT through the late evening hours. Gusts will subside near 00z. A surface cold front will push across the region late in the effective period with west/northwest winds increasing for a few hours behind the front. Foltz .PREV DISCUSSION... /ISSUED 900 PM MDT Sun Oct 6 2013/ Have made minor adjustments to the sky and wind grids and will issue an update this evening. Surface winds have decreased over the plains and have adjusted accordingly. The RUC continues to indicate a tightening of the surface gradient after 07z and HRRR analysis also supports mid level winds strengthening around this time along the Northern Rocky Mountain Front. This gives some corroboration for the high wind warning that goes in effect for this area at 09z. A chinook arch remains in place adjacent to the northern front range and have adjusted sky grids to better define its location. Temperatures look reasonable. Emanuel && .PRELIMINARY POINT TEMPS/POPS... GTF 48 70 42 53 / 0 0 0 10 CTB 46 67 40 53 / 0 0 10 20 HLN 36 68 39 53 / 0 10 10 20 BZN 30 67 36 54 / 0 0 0 20 WEY 24 56 31 47 / 0 0 0 20 DLN 33 63 33 49 / 0 0 10 20 HVR 40 74 41 60 / 0 0 0 10 LWT 37 71 37 53 / 0 0 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING from 3 AM Monday to 6 AM MDT Tuesday Northern Rocky Mountain Front. && $$ weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
333 AM EDT MON OCT 7 2013 .SYNOPSIS... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL CROSS LATE TONIGHT. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THIS FRONT AND MOVE NEAR THE AREA TUESDAY AND WEDNESDAY...PRODUCING WIDESPREAD RAIN AND MUCH COOLER TEMPERATURES. A DRYING AND WARMING TREND WILL BEGIN LATE IN THE WEEK AS HIGH PRESSURE BUILDS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...A STREAM OF SHOWERS ORIGINATING FROM THE GULF STREAM WATERS OFF THE GA/FL COAST CONTINUES TO MOVE NORTH INTO EASTERN SC EARLY THIS MORNING. SYNOPTIC MODELS 24 HOURS AGO WERE NOT ABLE TO CAPTURE THIS FEATURE...BUT RECENT HIGH-RESOLUTION MODELS LIKE THE HRRR AND NSSL WRF SEE IT WELL AND INDICATE THE "STREAMER" WILL CONTINUE THROUGH THE MORNING HOURS WITH SIGNIFICANT RAINFALL TOTALS POSSIBLE ACROSS EASTERN SOUTH CAROLINA. STRONG UPPER LEVEL LOW PRESSURE ACROSS THE SOUTHERN GREAT LAKES IS THE SAME SYSTEM RESPONSIBLE FOR THE RECORD-BREAKING EARLY SNOW ACROSS WESTERN SOUTH DAKOTA A COUPLE DAYS AGO. THIS UPPER SYSTEM WILL LIFT NORTHEAST...WHILE A VORTICITY MAXIMUM AT THE BASE OF THE UPPER TROUGH ALONG THE GULF COAST SLOWS AND BEGINS TO FORM A CLOSED LOW LATE TONIGHT. THE SURFACE PATTERN MIRRORS THE 500 MB CHART WITH AN EASTWARD-MOVING COLD FRONT LOCATED JUST AHEAD OF THE UPPER TROUGH. THIS FRONT WILL SLOW ITS PROGRESS AS SURFACE LOW PRESSURES DEVELOPS IN IN THE FLORIDA PANHANDLE. SHOWER AND T-STORM CHANCES ARE VERY HIGH TODAY...PROBABLY AT LEAST 90 PERCENT COVERAGE ACROSS THE EASTERN CAROLINAS. THIS MORNING`S HEAVY BAND OF SHOWERS ACROSS EASTERN SOUTH CAROLINA SHOULD SOAK THE PEE DEE AND INTERSTATE 95 CORRIDOR THROUGH MID-MORNING...SHIFTING EAST FROM MYRTLE BEACH THROUGH WHITEVILLE AND ELIZABETHTOWN BY NOON...THEN FINALLY REACHING THE CAPE FEAR AREA INCLUDING WILMINGTON BY THE MID-AFTERNOON HOURS. FROM A BROAD-SCALE PERSPECTIVE MANY AREAS SHOULD SEE TWO-THIRDS TO ONE INCH OF RAIN TODAY...BUT WITH TRAINING CONVECTION UNDOUBTEDLY A FEW SPOTS WILL RECEIVE 2-3 INCHES OR MORE. SEVERE WEATHER POTENTIAL IS NOT ZERO...BUT IS LESS THAN EXPECTED YESTERDAY DUE TO WEAKENING LOW-LEVEL WIND FIELDS AND OVERALL MODEST INSTABILITY. IN FACT IT APPEARS ISOLATED FLOODING MAY BECOME A LARGER FACTOR TO CONTEND WITH THAN SEVERE WEATHER. SHOULD A THUNDERSTORM BECOME SEVERE TODAY...WET MICROBURSTS APPEAR TO BE THE MOST SIGNIFICANT THREAT. TONIGHT THE PRESSURE GRADIENT BETWEEN THE LOW OVER NORTHERN FLORIDA AND HIGH PRESSURE STRENGTHENING OVER PENNSYLVANIA SHOULD PRODUCE A NORTHERLY SURGE THAT WILL REACH OUR AREA A FEW HOURS BEFORE SUNRISE. THIS SHALLOW COLD AIRMASS WILL UNDERCUT THE OTHERWISE WARM AND HUMID AIR PRESENT...PRODUCING GUSTY WINDS AND SUDDENLY FALLING TEMPERATURES. PRECIPITATION CHANCES WILL CONTINUE AS WELL... ESPECIALLY ALONG THE COAST...BUT ISENTROPIC PROCESSES WILL BECOME MORE DOMINANT WITH TIME AS INSTABILITY WANES AND VEERING LOW LEVEL WINDS ADVECT ATLANTIC MOISTURE BACK ONSHORE. POPS TONIGHT RANGE FROM 80 PERCENT ALONG THE COAST TO 60 PERCENT IN FLORENCE AND DARLINGTON. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...SLOW MOVING UPPER LOW WILL EJECT OUT OF THE GULF OF MEXICO AND DRIFT NORTHEAST THROUGH THE PERIOD...SPAWNING A WAVE OF LOW PRESSURE ALONG A COLD FRONT STALLED ON THE COAST. STRONG VORT MAX ACROSS SOUTHEAST TEXAS WILL MOVE INTO THE GULF AND THEN DRIFT NORTHEAST OVERHEAD THE CAROLINAS TUESDAY AND WEDNESDAY. THIS SPAWNS A SURFACE WAVE ALONG A COLD FRONT WHICH WILL BE STALLED RIGHT ON THE COAST...AND WILL KEEP UNSETTLED WEATHER THROUGH THE PERIOD. GUIDANCE IS IN GOOD AGREEMENT THAT BOTH TUESDAY AND WEDNESDAY WILL BE WET...A SIGNIFICANT CHANGE FROM MODELS LAST NIGHT. AS THE FRONT STALLS JUST OFFSHORE...ABUNDANT TROPICAL MOISTURE REMAINS IN PLACE. THIS SERVES AS THE FUEL FOR PERIODS OF MDT/HVY RAIN TUE AND WED AS THE UPPER LOW MOVES OVERHEAD. ADDITIONALLY...ISENTROPIC LIFT OVER THE DEVELOPING WEDGE-HIGH PRESSURE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA. WPC IS SHOWING WIDESPREAD 1-2 INCHES OF QPF...MOST ACROSS THE CAPE FEAR REGION TUE/WED. THIS MAY BE A BIT HIGH...BUT CERTAINLY SHOWS THE POTENTIAL WITHIN THE TROPICAL MOISTURE PLUME. IN ADDITION TO THE UNSETTLED WEATHER...TEMPS WILL BE WELL BELOW NORMAL BOTH TUE AND WED THANKS TO THE WEDGE HIGH PRESSURE AND CLOUDS/RAIN. STRONG LOW LVL CAA DEVELOPS EARLY TUESDAY...AND HAVE SHOWN AN ATYPICAL DIURNAL CURVE WITH MAX TEMPS BEING REACHED FIRST THING TUESDAY MORNING...BEFORE FALLING THROUGH THE DAY. HIGHS ON TUESDAY WILL REACH ONLY THE MID/UPR 60S...AGAIN...EARLY IN THE DAY...AND THEN FALL INTO THE LOW 60S/UPR 50S BY EVE. THIS COMBINES WITH STRONG NE WINDS WHICH MAY GUST TO 30 MPH...AND TUESDAY WILL FEEL MORE LIKE NOVEMBER IN SEATTLE THAN OCTOBER IN WILMINGTON! LOWS TUESDAY NIGHT WILL SHOW VERY LITTLE DIURNAL RANGE...DROPPING ONLY INTO THE MID 50S INLAND...AROUND 60 AT THE COAST. LITTLE IMPROVEMENT WEDNESDAY...BUT ANY IMPROVEMENT WILL BE WELCOMED AFTER TUESDAY! CLOUDS AND RAIN PERSISTING WILL AGAIN LIMIT WARMING IN THE WEDGE SETUP...AND HIGHS WILL PEAK IN THE UPR 60S INLAND...LOW 70S NEAR THE COAST. LOWS WED NIGHT WILL BE SIMILAR TO TUESDAY NIGHT...UPR 50S TO LOW 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...ONE MORE UNSETTLED DAY THURSDAY AS VERY SLOW MOVING UPPER LOW AND SURFACE WAVE WILL FINALLY MOVE OFF TO THE NORTHEAST AND ALLOW FOR DRYING ACROSS THE AREA. GUIDANCE IN DISAGREEMENT AS TO HOW LONG IT WILL TAKE FOR DRYING TO OCCUR...BUT WITH UPPER LOW EMBEDDED WITHIN THE 5H RIDGE...THUS MOVING VERY SLOWLY...WILL LEAN ON THE SLOWER SOLUTION AND KEEP SCHC POP ACROSS NE ZONES EARLY THURSDAY BEFORE THE ENTIRE AREA DRIES OUT. BEYOND THURSDAY...HEIGHTS GRADUALLY RISE AND THE WEDGE SLOWLY BREAKS DOWN...ALLOWING FOR MUCH MORE SUNSHINE AND TEMPS WARMING BACK TOWARDS CLIMO OR ABOVE BY THE WKND. GFS/EURO/CMC STILL DEPICT A SECONDARY AREA OF LOW PRESSURE DEVELOPING WELL OFFSHORE AND THEN RETROGRADING BACK TO THE SW SAT/SUN TOWARDS THE COAST. WHILE THIS HAS BEEN A PERSISTENT FEATURE IN THE EXTENDED GUIDANCE...LITTLE AGREEMENT IN SPECIFIC PLACEMENT AND WHETHER ANY IMPACTS WILL BE FELT LOCALLY. WILL KEEP INHERITED SILENT POP FOR D6/D7 WITH TEMPS RIGHT AROUND NORMAL FOR MID-OCTOBER. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... AS OF 06Z...BAND OF SHOWERS EMANATING FROM THE ATLANTIC OCEAN NEAR CHARLESTON WILL AFFECT FLORENCE AND LUMBERTON EARLY THIS MORNING. THE BIGGEST THREAT WILL BE TRANSIENT LOW CEILINGS NEAR MODERATE RAINFALL. AT FLORENCE THERE IS A MODERATE CHANCE OF SUB-1000 FOOT CEILINGS THROUGH 09Z...WITH LOW PROBABILITIES OF IFR CIGS THROUGH DAYBREAK. AT LUMBERTON IFR PROBABILITIES ARE LOWER BUT CANNOT TOTALLY BE RULED OUT. FOR THE COASTAL AIRPORTS (ILM, MYR, CRE) THE BULK OF THE SHOWER ACTIVITY OVER THE NEXT 6 HOURS SHOULD REMAIN TO THE WEST...WITH GENERALLY VFR TO OCCASIONAL MVFR CONDITIONS EXPECTED. AN APPROACHING COLD FRONT WILL BRING SHRA TO OUR FORECAST AREA LATER TODAY. VFR/MVFR CONDITIONS SHOULD PREVAIL...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. FCST SOUNDINGS SUGGEST THERE WILL BE ENOUGH INSTABILITY FOR AT LEAST ISOLATED T-STORMS...SO HAVE INCLUDED VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...A NORTH-TO-SOUTH ORIENTED COLD FRONT JUST ENTERING THE APPALACHIANS WILL MOVE EASTWARD TODAY...DECELERATING AS IT APPROACHES THE COAST TONIGHT. SOUTH-SOUTHEAST WINDS 15-20 KNOTS THIS MORNING SHOULD DIMINISH THIS AFTERNOON. LOW PRESSURE DEVELOPING ALONG THE FRONT NEAR THE FLORIDA PANHANDLE WILL BECOME OUR DOMINANT WEATHER FEATURE TONIGHT. THE INCREASING PRESSURE GRADIENT BETWEEN THIS LOW AND STRENGTHENING HIGH PRESSURE OVER PENNSYLVANIA WILL LEAD TO INCREASING WIND SPEEDS LATE TONIGHT. A SURGE IS EXPECTED TO DEVELOP A FEW HOURS BEFORE DAYBREAK...WITH WINDS TURNING NORTH-NORTHEAST AND INCREASING TO 15-20 KT. SEAS CURRENTLY RANGE FROM 5 FT OUT AT THE FRYING PAN SHOALS BUOY...TO 3-4 FT CLOSER TO SHORE. STEADY ONSHORE WINDS THIS MORNING SHOULD BRING 5-FOOTERS INTO THE 10-20 MILE WATERS...AND AN EXERCISE CAUTION HEADLINE WILL BE APPENDED TO THE FORECAST THROUGH EARLY AFTERNOON. DIMINISHING WINDS THIS AFTERNOON WILL ALLOW SEAS TO SUBSIDE...BUT LOOK FOR BUILDING SEAS AGAIN VERY LATE TONIGHT IN THE NORTHERLY SURGE. SHOWERS AND THUNDERSTORMS CURRENTLY ACROSS EASTERN SOUTH CAROLINA WILL IMPACT THE SC COASTAL WATERS THIS MORNING. GUSTY WINDS AND REDUCED VISIBILITY IN HEAVY RAINFALL ARE EXPECTED. THIS ACTIVITY WILL MOVE EAST AND AFFECT THE NC WATERS THIS AFTERNOON. PRECIPITATION SHOULD BECOME LESS THUNDERY TONIGHT BUT SHOULD OTHERWISE CONTINUE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...STRONG NE WINDS WILL PERSIST THROUGH THE PERIOD AS THREE FEATURES COMBINE TO CREATE POOR MARINE CONDITIONS INTO MID-WEEK. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT STALLED JUST OFFSHORE...ENHANCING THE ALREADY PINCHED GRADIENT DUE TO A WEDGE OF HIGH PRESSURE FORMING DOWN THE COAST. THIS CREATES GUSTY NE WINDS TUESDAY AND WEDNESDAY...WITH SPEEDS OF 15-25 KTS TUESDAY...DROPPING SLIGHTLY TO 15-20 KTS ON WEDNESDAY. GUSTS TO 30 KTS ARE POSSIBLE...ESPECIALLY ON TUESDAY. THIS CREATES SHORT-PERIOD AND STEEP WIND WAVES REACHING 4-7 FT TUESDAY...BEFORE FALLING SLOWLY TO 3-5 FT BY WEDNESDAY EVE. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR ALL OF TUESDAY AND PARTS OF WEDNESDAY BEFORE CONDITIONS SLOWLY BEGIN TO IMPROVE LATE IN THE PERIOD. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...GUSTY N/NE WINDS TO START THE PERIOD WILL GRADUALLY EASE BY THE END OF THE WEEK AS HIGH PRESSURE WEDGE BEGINS TO BREAK DOWN JUST INLAND FROM THE WATERS. TIGHT GRADIENT THURSDAY KEEPS N/NE WINDS AT 15-20 KTS...BUT THIS WILL WEAKEN ON FRIDAY...HELPING WINDS TO FALL TO AROUND 10 KTS AND BACK MORE TO THE NORTH. WAVE HEIGHTS INITIALLY WILL BE 3-5 FT AND A SCEC MAY BE REQUIRED...BUT THESE WILL FALL QUICKLY ON FRIDAY TO 2-3 FT THANKS TO THE DECREASED WINDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...TRA MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
130 AM EDT MON OCT 7 2013 .SYNOPSIS... A FEW SHOWERS WILL CONTINUE THIS AFTERNOON AND TONIGHT. A STRONG COLD FRONT WILL CROSS THE CAROLINAS LATE MONDAY...BRINGING A PERIOD OF SHOWERS AND THUNDERSTORMS. MOISTURE AND BLUSTERY CONDITIONS WILL CONTINUE TUESDAY AND WEDNESDAY. A DRYING TREND SHOULD DEVELOP LATER IN THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 130 AM MONDAY...AN EARLY MORNING UPDATE HAS BEEN MADE TO RAISE POPS ACROSS THE SC PEE DEE REGION INTO THE LIKELY (60-70 PERCENT) RANGE. SHOWERS ADVECTING NORTHWARD FROM THE CHARLESTON VICINITY WILL MOVE OVERHEAD FOR THE NEXT SEVERAL HOURS. ALSO MADE LARGE INCREASES TO FORECAST SKY COVER. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... STREAMER TYPE CONVECTION FROM OFF THE ATL WATERS TO CONTINUE OVERNIGHT. SPEED CONVERGENCE IN THE LOWER LEVELS AS A RESULT OF THE SE-S ONSHORE FLOW CONTINUES TO FIRE LOW TOPPED CONVECTION ACROSS THE ILM COASTAL WATERS AND ONSHORE. WITH THE DAYS INSOLATION OVERWITH...THE ACTIVITY THAT MOVES ONSHORE WILL FOR THE MOST PART BE UNABLE TO SUSTAIN ITS INTENSITY LET ALONE ITS INTEGRITY AS IT PROGRESSES FURTHER INLAND. THIS CURRENTLY IS BEING PLAYED OUT AS ONE LOOPS THE KLTX AND SURROUNDING RADARS. ALTHOUGH CURRENT LTG REMAINS LACKING...THE ACTIVITY OVER THE ADJACENT ATL WATERS WILL HAVE INCREASING AND DEEPER INSTABILITY OVERNIGHT AS ACTIVITY PASSES OVER SSTS THAT ARE AROUND 80 DEGREES. WOULD NOT BE SURPRISED FOR THUNDER TO OCCUR...AND POSSIBLY REACH AND PUSH ONSHORE LATER OVERNIGHT. NO PRONOUNCED UPPER S/W TROF OR VORT TO AFFECT THE FA OVERNITE THAT WOULD PROVIDE ADDITIONAL FORCING TO FURTHER PROMOTE THUNDER. THIS IS NOT PROGGED BY THE MODELS TO OCCUR UNTIL DAYTIME MONDAY WHILE APPROACHING FROM THE WEST. HOWEVER...ENOUGH CAPE MANIFESTS ACROSS THE FA TOWARD DAYBREAK MONDAY AS EXHIBITED BY THE LATEST HRRR MODEL RUN...TO AT-LEAST MENTION ISOLATED THUNDER DURING THIS TIME FRAME. OVERALL...POPS ACROSS THE FA OVERNIGHT WILL RANGE BETWEEN 25 TO 50 PERCENT. WIDESPREAD 70+ SFC DEWPOINTS CURRENTLY ACROSS THE FA. DO NOT SEE MUCH OF A DOWNWARD OR DECREASING TREND OVERNITE WITH SFC DEWPOINTS. AS A RESULT...LOOKING AT WIDESPREAD 70 TO 75 DEGREE LOWS FOR TONIGHT...WHICH IS NEARLY 15 DEGREES HIGHER THAN CLIMO NORMS FOR THIS TIME OF THE YEAR. MUST BE GLOBAL WARMING AGAIN. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE SHORT TERM CONTINUES TO TREND TO A VERY ACTIVE PERIOD MOSTLY AS A RESULT OF MODEL CONSENSUS ON THE EVENTS FOR TUESDAY. THE 1200 UTC GFS AND NAM ARE IN AGREEMENT ON A MID LEVEL LOW CUTTING OFF IN THE SOUTHEAST TUESDAY WITH BROAD ISENTROPIC LIFT DEVELOPING BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND THE ASSOCIATED SURFACE LOW/TROUGH TO THE SOUTH. IT WILL BE A RATHER WET AND RAW DAY AS GUIDANCE SHOWS HIGH TEMPERATURES REMAINING IN THE 60S WITH WIND SPEEDS FROM THE EAST/NORTHEAST AT 10-15 MPH. THE LACK OF SATURATION IN THE 305K LAYER AND MODEST ISENTROPIC LIFT...WINDS ARE ACTUALLY FAIRLY LIGHT ABOVE THE SURFACE MAY KEEP QPF VALUES MODEST. HOWEVER SUBSEQUENT SHIFTS MAY WANT TO INCREASE POPS ESPECIALLY LATE IN THE PERIOD AS THE COLUMN SHOWS BETTER SATURATION IN THIS LAYER. AS FOR THE EVENTS MONDAY...LITTLE CHANGE WAS WARRANTED WITH THE FORECAST AS THE MODELS ARE STILL IN AGREEMENT ON THE FRONT...CURRENTLY LOCATED IN THE TENNESSEE VALLEY MOVING ACROSS MONDAY EVENING. MAINTAINED THE LIKELY TO CATEGORICAL POPS WITH THE SAME TEMPORAL TRENDS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...WEDNESDAY NO LONGER LOOKING DRY AS PREVIOUSLY THOUGHT. A WEAK SOUTHERN BRANCH SHORTWAVE LIFTS OUT OF THE GULF OF MEXICO EARLY IN THE WEEK AND CROSSES THE CAROLINAS WEDNESDAY. THERE IS STILL COPIOUS/DEEP MOISTURE IN PLACE AS THE THE MONDAY COLD FRONT ONLY SEEMS TO REMOVE THE SURFACE MOISTURE. THE UPPER SYSTEM INDUCES A WAVE ALONG THE BOUNDARY WELL OFFSHORE ON WEDNESDAY BUT ITS LOCATION IS NOT AGREED UPON BY VARIOUS GUIDANCE. INTERESTINGLY THE EC DOESN`T REALLY DEVELOP A WAVE BUT STILL HAS QPF AS THE UPPER SHORTWAVE MOVES ATOP THE WEDGE. WILL INTRODUCE LOW CHC POPS MAINLY ALONG THE COAST. MOST IF NOT ALL OF THE REMAINDER OF THE PERIOD WILL BRING DRY WEATHER AS BUILDING UPPER LEVEL RIDGE AND SOUTHWARD SPRAWLING SURFACE HIGH OCCUPY OUR LONGITUDE. THE GFS CONTINUES TO SHOW THAT OUR WEDNESDAY SHORTWAVE EVENTUALLY BEARS A LOW OFF THE DELMARVA COAST THAT RETROGRADES AND MAY BRING SOME WEEKEND POPS. FOR NOW THIS LOOKS JUST ANOMALOUS ENOUGH TO CAP POPS AT SLIGHT. THE EC ALSO SHOWS SOME ATLANTIC DEVELOPMENT BUT NOT THE RETROGRADING MOTION. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...BAND OF SHOWERS EMANATING FROM THE ATLANTIC OCEAN NEAR CHARLESTON WILL AFFECT FLORENCE AND LUMBERTON EARLY THIS MORNING. THE BIGGEST THREAT WILL BE TRANSIENT LOW CEILINGS NEAR MODERATE RAINFALL. AT FLORENCE THERE IS A MODERATE CHANCE OF SUB-1000 FOOT CEILINGS THROUGH 09Z...WITH LOW PROBABILITIES OF IFR CIGS THROUGH DAYBREAK. AT LUMBERTON IFR PROBABILITIES ARE LOWER BUT CANNOT TOTALLY BE RULED OUT. FOR THE COASTAL AIRPORTS (ILM, MYR, CRE) THE BULK OF THE SHOWER ACTIVITY OVER THE NEXT 6 HOURS SHOULD REMAIN TO THE WEST...WITH GENERALLY VFR TO OCCASIONAL MVFR CONDITIONS EXPECTED. AN APPROACHING COLD FRONT WILL BRING SHRA TO OUR FORECAST AREA LATER TODAY. VFR/MVFR CONDITIONS SHOULD PREVAIL...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. FCST SOUNDINGS SUGGEST THERE WILL BE ENOUGH INSTABILITY FOR AT LEAST ISOLATED T-STORMS...SO HAVE INCLUDED VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY.&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM MONDAY...NO SIGNIFICANT CHANGES NECESSARY. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... LATEST PIER AND BUOY OBS ACROSS THE AREA WATERS INDICATE WINDS ARE RUNNING CLOSE TO THE CURRENT FORECAST TREND. WILL ONLY MAKE SLIGHT ADJUSTMENTS TO WIND DIRECTIONS...WITH SE-S BEING ADVERTISED INSTEAD OF INDICATING A SSE WIND DIRECTION. LATEST HRRR SFC WIND OUTPUT ACROSS THE ILM WATERS CONTINUES WITH 10-15 KT...INCREASING TO 15-20 KT BY DAYBREAK. THIS ONSHORE FLOW WILL BUILD SIGNIFICANT SEAS RATHER QUICKLY OVERNIGHT...WITH THE MAJORITY OF THE ILM COASTAL WATERS AT 3 TO 5 FT BY DAYBREAK MONDAY. BUILDING WIND DRIVEN WAVES AT 4 TO 6 SECOND PERIODS WILL DOMINATE THE WAVE SPECTRUM OVERNIGHT. THE SMALL ESE 9 TO 11 SECOND PERIOD GROUND SWELL WILL PROVIDE NO AID FOR INCREASING THE SIG. SEAS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE MARINE COMMUNITY WILL SEE RATHER CHANGEABLE CONDITIONS THROUGH THE PERIOD. EXPECT A SOUTHEAST FLOW OF 15-20 KNOTS INITIALLY. THIS FLOW WILL WEAKEN AND VEER TO THE SOUTH THEN SOUTHWEST BY THE END OF THE DAY MONDAY. A FRONT WILL MOVE ACROSS THE WATERS AROUND 0600 UTC TUESDAY WITH A NORTH TO NORTHEASTERLY FLOW DEVELOPING BY 1200 TUESDAY. SPEEDS WILL INCREASE AS WELL TO 15-20 KNOTS BY THIS TIME. THIS PATTERN WILL REMAIN IN PLACE THROUGH THE END OF THE PERIOD. SIGNIFICANT SEAS ARE 3-5 FEET EARLY IN THE PERIOD WITH A DECREASE MONDAY EVENING. SEAS WILL INCREASE ONCE AGAIN TUESDAY ESPECIALLY LATER IN THE DAY TO POSSIBLY SMALL CRAFT CRITERIA. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...LONG DURATION OF NORTHERLY FLOW EXPECTED. HIGH PRESSURE WEDGING IN EAST OF THE APPALACHIANS TO PRODUCE A MODERATE GRADIENT ACROSS THE WATERS. A WAVE OF LOW PRESSURE SHOULD DEVELOP SOMEWHERE ALONG COLD FRONT STALLED WELL OFFSHORE BUT ITS LOCATION IS UNCERTAIN AT THIS POINT. THIS IS EXPECTED TO MODULATE THE STRENGTH OF THE GRADIENT AND HAVE AN IMPACT ON THE STRENGTH OF THE GRADIENT PINCH AND WHETHER OR NOT WELL NEED ANY HEADLINES OR EVEN BORDERLINE AND SHORT-LIVED ADVISORY OUT ALONG FRYING PAN SHOALS. WHEREVER THIS LOW DEVELOPS...IT WILL PULL AWAY TO THE NORTH AND EAST THURSDAY INTO FRIDAY AND THE SURFACE HIGH WILL REMAIN ENTRENCHED ACROSS THE EASTERN U.S. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH/TRA SHORT TERM...SHK LONG TERM...MBB AVIATION...BJR/TRA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
531 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY. A WEAK LOW PRESSURE AREA MAY DEVELOP TO OUR SOUTH DURING THE MIDDLE OF THE WEEK AND CRAWL SLOWLY NORTHWARD THROUGH THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CLOUDS NOW COVER MOST OF THE AREA...BUT RAINFALL JUST STARTING TO ENTER THE WESTERN HIGHLANDS. THE COLD FRONT SEEMS TO BE JUST AT THE LEADING EDGE OF THE RAIN. A STEADY PROGRESSION OF BOTH THE FRONT AND THE RAIN SHIELD WILL OCCUR THROUGH THE DAY. ALL MODELS IN VERY GOOD AGREEMENT RIGHT NOW. CONFIDENCE IS HIGH IN THE FORECAST TIMING. SREF RAINFALL AMOUNTS OF BETWEEN ONE AND ONE AND A HALF INCHES SEEMS REASONABLE. THEE DURATION OF THE RAIN SHOULD BE ABOUT 6 HRS...WHICH SHOULD KEEP ANY FLOODING WORRIES TO A BARE MINIMUM. SOME PONDING OF WATER IN THE NORMAL PLACES...BUT NOT EVEN SMALL STREAM FLOODING. MUCH OF THE AREA HAS BEEN QUITE DRY LATELY. THE MAIN FORECAST PROBLEM TODAY IS HOW UNSTABLE IT WILL GET OVER THE EASTERN HALF OF THE AREA THIS AFTERNOON. CLOUDS COVER THE AREA AT 5 AM AND DEEP SERLY FLOW AHEAD OF THE FRONT SHOULD ONLY REINFORCE THE CLOUD COVER. TEMPS MAY BE AT THEIR MAXES IN THE WESTERN HIGHLANDS...BUT THE EAST COULD HAVE 6-7 HRS OF POTENTIAL HEATING. THE COLD FRONT SHOULD BE PASSING THROUGH STATE COLLEGE ABOUT NOON/1 PM...AND HARRISBURG AROUND 2/3 PM. AREAS TO THE EAST OF THE FRONT WHICH CAN GENERATE SOME MODERATE INSTABILITY COULD HAVE SOME THUNDERSTORMS DEVELOP IN THE VERY STRONG SWRLY FLOW AHEAD OF THE FRONT. THE WINDS JUST 1-2KFT OFF THE GROUND WILL BE RACING AT 50KTS. IT WON/T TAKE MUCH TO MIX THAT DOWN...BUT THE CLOUDS WILL CUT DOWN ON HEATING WHICH WILL COUNTER-BALANCE THE THREAT. SPC DOES PLACE THE ERN HALF OF THE AREA INTO SLIGHT RISK. BUT THE LACK OF HEATING WILL BE THE TRICK. NAM MAKES LI AROUND -4 WITH TT AT 46 AND CAPE IN THE 1000+ RANGE AT MDT LATE THIS MORNING. SO A MENTION OF GUSTY WINDS IS AN EASY CALL...BUT MENTIONING SEVERE IS A BIT OF A STRETCH. CLEAR SLOT WILL LIKELY DEVELOP AFTER THE RAIN SHIELD MOVES TO THE EAST IN ALL LOCATIONS...BUT THE WNW FLOW BEHIND IT WILL LIKELY BRING CLOUDS BACK INTO THE NW/LAURELS THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... DRYING TAKES PLACE VERY QUICKLY AFTER FROPA. ALL PRECIP SHOULD BE TO THE EAST AT THE START OF THE PERIOD. SOME POST-FRONTAL COLD ADVECTION CLOUDS ARE POSSIBLE IN THE MOUNTAINS TONIGHT...BUT CLEAR SKIES EXPECTED ELSEWHERE. TEMPS WILL TAKE A TUMBLE INTO THE 40S TONIGHT...AND RIVER VALLEY FOG IS POSSIBLE. BUT THE WINDS WILL STAY UP FOR AT LEAST THE FIRST PART OF THE NIGHT. ANY CLOUDS WILL DISSIPATE ON TUESDAY...BUT SCT DIURNAL CU MAY DEVELOP UNDER THE COLD POCKET ALOFT AIR WITH HIGH AMBIENT MOISTURE FROM THE RAIN TODAY. 8H TEMPS DROP INTO THE LOWER SINGLE DIGITS BY TUES MORNING AND HOLD THERE FOR THE DAYTIME. MAXES WILL THEREFORE BE HELD TO THE 50S IN THE MOUNTAINS AND LOWER TO MID 60S ELSEWHERE THANKS TO THE DOWNSLOPE IN THE SERN HALF. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HAVE TWEAKED WED NIGHT-THURS NIGHT TO REFLECT THE POSSIBLE EFFECTS OF A LOW SLATED TO DEVELOP TO THE SOUTH ALONG THE EASTERN SEABOARD. THIS COULD BRING SHOWERS UP INTO THE SRN/SERN PARTS OF THE AREA...AND HOLD TEMPS DOWN A BIT AS WELL. PREV DISCO... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS CONTINUE ACROSS WESTERN AIRFIELDS EARLY THIS MORNING AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER THIS MORNING. CIGS AT SUSQUEHANNA RIVER VALLEY TAF SITES...MDT...LNS AND IPT HAVE FALLEN INTO MVFR RANGE AS GUSTY S/SE WINDS...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES HAVE PUSHED MARINE LAYER FROM THE ATLANTIC OCEAN TO PUSH NORTHWESTWARD ACROSS CWA. EXPECT EXPANSION OF THE MVFR/IFR STRATOCU DECK AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. FOCUS THEN TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...DANGELO/CERU AVIATION...GARTNER/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
313 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE WEEK. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... COLD FRONT IS VISIBLE ON RADAR MOSAIC NEAR KPIT AND JUST PAST KERI. WIND SHIFT/PRESSURE RISES ARE SEEN IN MANY OBS OVER ERN OHIO. RAIN SHIELD IS BEHIND THE FRONT...BUT STRONG SRLY LLVL JET WILL LIKELY KEEP THE SHOWERS MOVING RIGHT ALONG WITH THE FRONT THROUGH THE REST OF THE NIGHT AND EARLY THIS MORNING. LITTLE SFC- BASED INSTABILITY IS POSSIBLE BEFORE SUNRISE. GUSTY WIND SHOULD CONTINUE AS THE PRESSURE GRADIENT IS TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS CONTINUE ACROSS WESTERN AIRFIELDS EARLY THIS MORNING AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER THIS MORNING. CIGS AT SUSQUEHANNA RIVER VALLEY TAF SITES...MDT...LNS AND IPT HAVE FALLEN INTO MVFR RANGE AS GUSTY S/SE WINDS...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES HAVE PUSHED MARINE LAYER FROM THE ATLANTIC OCEAN TO PUSH NORTHWESTWARD ACROSS CWA. EXPECT EXPANSION OF THE MVFR/IFR STRATOCU DECK AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. FOCUS THEN TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...GARTNER/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
120 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE WEEK. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... COLD FRONT IS VISIBLE ON RADAR MOSAIC NEAR KPIT AND JUST PAST KERI. WIND SHIFT/PRESSURE RISES ARE SEEN IN MANY OBS OVER ERN OHIO. RAIN SHIELD IS BEHIND THE FRONT...BUT STRONG SRLY LLVL JET WILL LIKELY KEEP THE SHOWERS MOVING RIGHT ALONG WITH THE FRONT THROUGH THE REST OF THE NIGHT AND EARLY THIS MORNING. LITTLE SFC- BASED INSTABILITY IS POSSIBLE BEFORE SUNRISE. GUSTY WIND SHOULD CONTINUE AS THE PRESSURE GRADIENT IS TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS MAJORITY OF CENTRAL PA AT MIDNIGHT AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER TONIGHT/EARLY MON. BIGGEST AVIATION CONCERN FOR NEXT SEVERAL HOURS WILL BE A GUSTY S/SE WIND...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES. MOIST FLOW IS ALLOWING A MARINE LAYER FROM THE ATLANTIC TO PUSH NORTHWESTWARD ACROSS CWA...RAISING DEWPOINTS BY NEARLY 10F. BIGGER IMPACTS OF THIS MARINE LAYER ARE BEGINNING TO DEVELOP AS POTENT SOUTHERLY LOW-LEVEL JET SLIDES EAST FROM OHIO VALLEY...PROVIDING THE LIFT TO INITIATE DEVELOPMENT OF AN MVFR/IFR STRATOCU DECK. THESE CLOUDS WILL DEVELOP FIRST IN THE MOIST AIRMASS OVER EASTERN SECTIONS...AND KIPT HAS ALREADY DROPPED TO MVFR...AND SPREAD INTO OTHER AREAS AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. THEN FOCUS TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1206 AM EDT MON OCT 7 2013 .SYNOPSIS... THE REGION REMAINS IN THE WARM SECTOR OF A LOW MOVING THROUGH THE UPPER GR LAKES. THE ASSOCIATED COLD FRONT WILL MOVE THROUGH ON MONDAY AS TROPICAL MOISTURE FLOWS UP INTO THE STATE. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE NEW WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE COLD FRONT IS MOVING INTO EASTERN OHIO ACCOMPANIED BY AN AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDERSTORMS. LOCALLY...THE CWA IS DRY AND QUITE MILD. HAVEN`T REALLY CHANGED MUCH OF THE FORECAST DURING THE OVERNIGHT...STILL LOOKS GOOD FOR RAIN TO BE MOVING INTO WESTERN AREAS AROUND OR SHORTLY AFTER 06Z...AND SPREADING QUICKLY EAST AFTER THAT. THE STRONG...SOUTHERLY LLJ WILL SHIFT EAST FROM THE OHIO VALLEY AND INTO THE REGION OVERNIGHT. THIS WILL QUICKLY INCREASE SFC WINDS...WITH THE HIGHER TERRAIN AND LOCATIONS NORTH OF GAPS IN THE RIDGES SEEING WIND GUSTS OVER 30 MPH. INCREASED LARGE SCALE LIFT ASSOCIATED WITH THIS LLJ AND A SERIES OF UPPER SHORT WAVES LIFTING QUICKLY NNE AHEAD OF THE MAIN OHIO VALLEY TROUGH AND SFC COLD FRONT WILL LEAD TO THE DEVELOPMENT OF NUMEROUS SHOWERS AND EMBEDDED LOW TOPPED TSRA OVER THE WESTERN PA AFTER MIDNIGHT. THIS CONVECTION MAY REACH THE I-99/RT 220 CORRIDOR BETWEEN 10-12Z MONDAY. LOOK FOR ONE MORE NIGHT OF UNSEASONABLY MILD TEMPS WITH LOW IN THE 60-65F RANGE...THANKS TO SIMILARLY HIGH DEWPOINTS...AND THE INCREASING CLOUDS/WIND. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS MAJORITY OF CENTRAL PA AT MIDNIGHT AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER TONIGHT/EARLY MON. BIGGEST AVIATION CONCERN FOR NEXT SEVERAL HOURS WILL BE A GUSTY S/SE WIND...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES. MOIST FLOW IS ALLOWING A MARINE LAYER FROM THE ATLANTIC TO PUSH NORTHWESTWARD ACROSS CWA...RAISING DEWPOINTS BY NEARLY 10F. BIGGER IMPACTS OF THIS MARINE LAYER ARE BEGINNING TO DEVELOP AS POTENT SOUTHERLY LOW-LEVEL JET SLIDES EAST FROM OHIO VALLEY...PROVIDING THE LIFT TO INITIATE DEVELOPMENT OF AN MVFR/IFR STRATOCU DECK. THESE CLOUDS WILL DEVELOP FIRST IN THE MOIST AIRMASS OVER EASTERN SECTIONS...AND KIPT HAS ALREADY DROPPED TO MVFR...AND SPREAD INTO OTHER AREAS AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. THEN FOCUS TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
503 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 445 AM UPDATE...EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AT KCLT /09Z UPDATE/...COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS AFTN...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY AND EITHER MAY NOT MAKE IT TO KCLT OR ARRIVE AFTER MORNING MIXING BEGINS. CHANCES WARRANT A TEMPO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NLY WIND SHIFT ARRIVING EARLIER. IT IS EXPECTED JUST AFTER DAYBREAK IN THE MTNS...LATE MRNG FOOTHILLS AND UPPER PIEDMONT...EARLY AFTN ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. OUTLOOK...DRY AND COOL HIGH PRESSURE BUILDS IN MON NITE AND CONTINUES THRU THE WEEK. RESTRICTIONS SHUD BE LIMITED TO MORNING MTN VALLEY FOG. CONFIDENCE TABLE... 09-15Z 15-21Z 21-03Z 03-09Z KCLT MED 78% HIGH 81% HIGH 82% HIGH 100% KGSP HIGH 81% MED 68% HIGH 92% HIGH 100% KAVL MED 77% MED 79% HIGH 100% HIGH 100% KHKY HIGH 83% MED 74% HIGH 100% HIGH 100% KGMU HIGH 84% MED 78% HIGH 92% HIGH 100% KAND MED 76% MED 74% HIGH 93% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
337 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE EXTENDING DOWN THE SPINE OF THE APPALACHIANS. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT TSTMS...MOST NOTABLY A LOW END QLCS MOVING INTO THE NC PIEDMONT AND NERN UPSTATE ZONES. THIS REFLECTS THE STRONG SHEAR...20 KT 0-1KM WITH 0-3KM HELICITY OF OVER 200 M2/S2. SPC MESOANALYSIS SHOWS THE LINE ENTERING HIGHER SFC BASED CAPE OVER THE ERN PIEDMONT...THOUGH AS NOTED BY PREVIOUS SHIFTS THE JUICIEST VALUES WILL REMAIN FURTHER SOUTH. LATEST 04Z HRRR INDICATES SOME NEW DEVELOPMENT ALONG THE SRN END OF THIS LINE AS INDIVIDUAL CONVECTIVE ELEMENTS MOVE NORTHEAST...AND THIS MATCHES RADAR TRENDS OVER THE PAST HOUR OR SO. THE UNIDIRECTIONAL SHEAR AND STRONG MIDLEVEL WINDS ARE ALLOWING FOR TRAINING TO OCCUR THERE ALSO...AND THIS APPEARS TO BE THE MAIN HYDRO CONCERN AT THIS TIME. THE LINE LOOKS TO GRADUALLY SHIFT EASTWARD OVER THE PIEDMONT THRU DAYBREAK. DISCRETE CONVECTIVE ACTIVITY EARLIER THIS EVENING NEAR THE CHARLOTTE METRO DID DIMINISH...BUT THE ENVIRONMENT SEEMS TO BE PRIMED FOR REDEVELOPMENT AS THE SHORTWAVE MOVES IN LATER. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS AFTN...PRECEDED BY SHRA/TSRA. AN ORGANIZED LINE OF TSRA WILL MOVE THRU UPSTATE SC AND THE SRN NC PIEDMONT EARLY THIS AM. THIS LINE IS LIKELY TO BRING A PERIOD OF IFR CIGS/VSBY TO AFFECTED LOCATIONS...BUT TO HAVE A DIRECT IMPACT IT WILL HAVE TO BUILD ON ITS SRN END. WESTERLY GUSTS OF 15-20KT ALSO LIKELY ALONG THIS LINE. INDEED THE LINE MAY TRANSLATE NORTH OF THE FIELD...BUT CHANCES WARRANT A TEMPO. NONETHELESS...UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THE FRONT PUSHES THRU...WHEN VFR CONDITIONS RETURN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. ELSEWHERE...MORE OR LESS LIKE KCLT THOUGH TIMING EARLIER IN MOST REGARDS. MOST ORGANIZED CONVECTION WILL PUSH EAST OF KGSP/KGMU WITHIN THE FIRST COUPLE HRS OF THE TAF. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM OVERNIGHT. ANOTHER CLUSTER OF STORMS MAY AFFECT KAVL TOWARD DAYBREAK FOLLOWING AN EARLY MORNING LULL. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. OUTLOOK...DRY AND COOL HIGH PRESSURE BUILDS IN MON NITE AND CONTINUES THRU THE WEEK. RESTRICTIONS SHUD BE LIMITED TO MORNING MTN VALLEY FOG. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-07Z KCLT HIGH 86% HIGH 95% MED 76% HIGH 100% KGSP HIGH 94% MED 77% MED 79% HIGH 100% KAVL HIGH 93% MED 66% HIGH 100% HIGH 100% KHKY HIGH 88% MED 78% HIGH 94% HIGH 100% KGMU HIGH 93% HIGH 82% MED 78% HIGH 100% KAND HIGH 85% MED 77% HIGH 85% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1145 PM CDT SUN OCT 6 2013 .UPDATE...FOR AVIATION. && .AVIATION... 06Z TAFS...COLD FRONT HAS MOVED THROUGH THE AREA WITH FEW SHRA LINGERING AROUND CSV. CSV WILL HAVE SHRA ENDING BY 09Z WITH SOME FOG AND LOW CLOUDS POSSIBLE THROUGH THE REST OF THE NIGHT. FOR BNA AND CKV...DRIER AIR AND CLEARING IS MOVING IN BEHIND THE FRONT...BUT SOME MVFR FOG MAY DEVELOP TOWARD DAYBREAK. HIGH PRESSURE WILL DOMINATE DAYTIME MONDAY...WITH EXCELLENT VSBY... SCT CU AROUND 4 KFT AND NNW WINDS NEAR 10KT. 13 && .PREV DISCUSSION... /ISSUED 721 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REMOVE THE THROUGH LATE AFTERNOON WORDING AND TO TAILOR SHWRS PRESENTLY MAINLY E OF I-65 TO CONTINUE SLOWING MOVING EWD OUT OF MID STATE WITH SHWRS CONTINUING ACROSS THE PLATEAU COUNTIES ONLY GENERALLY AFTER MIDNIGHT. HAVE TAILORED SKY CONDITIONS ALSO TO REFLECT DECREASING CLOUDINESS W TO E ACROSS THE MID STATE AS THE NIGHT TIME HRS PROGRESS. CURRENT TEMPS IN LINE WITH FORECASTED LOW VALUES AS OF THIS TIME...THUS NO ADJUSTMENTS MADE TO OVERNIGHT LOW VALUES AS OF THIS TIME. 31 PREV DISCUSSION... /ISSUED 511 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO INTRODUCE A THROUGH THE LATE AFTERNOON HOURS GROUPING ALL COUNTIES TO DEAL WITH CURRENT AND EXPECTED SHORT TERM PROGRESSION OF SHWRS AND ISO TSTMS W TO E ACROSS MID STATE. TEMPS SHOULD FALL ACROSS THE ENTIRE MID STATE INTO THE UPPER 50S BY THE LATE AFTERNOON HRS. ALSO. 31 PREV DISCUSSION.../ISSUED 213 PM CDT SUN OCT 6 2013/ DISCUSSION...SURFACE FRONT HAS MADE IT EAST OF NASHVILLE, WITH A BROKEN LINE OF MODERATE TO HEAVY SHOWERS OCCURRING ALONG THE BOUNDARY. HRRR DOING A REASONABLE JOB WITH ONGOING ACTIVITY, AND THE SHORT-RANGE MODEL SHOWS NUMEROUS CELLS LASTING WELL PAST 00Z. SIGNIFICANTLY COOLER AIR AND LOWER DEW POINTS ARE OBVIOUSLY RUSHING IN BEHIND THE FRONT, EVEN AS SCATTERED SHOWERS CONTINUE DEVELOPING IN THE COLD POOL. EXPECT MOST OF THE ACTIVITY TO MOVE EAST OF THE AREA BY 06Z, WITH SHOWERS EXITING THE PLATEAU BY 12Z. A BROAD RIDGE OF HIGH PRESSURE WILL QUICKLY BUILD IN AND DRY OUT THE ATMOSPHERE AND KEEP A COOLER AIR MASS LOCKED IN PLACE OVER MIDDLE TENNESSEE THE REMAINDER OF THE WEEK. NO PRECIPITATION IS EXPECTED FROM TOMORROW THROUGH THE END OF THE 7-DAY FORECAST PERIOD. ROSE && .OHX WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1000 AM EDT Mon Oct 7 2013 .NEAR TERM [Rest of Today]... ---Updated at 10:00 AM EDT--- The remnant low formerly known as "Karen" was located about 30 miles or so south-southeast of St. George Island as of 13 UTC. The low will continue to slowly shift east today to near the mouth of the Suwannee River by late afternoon. A synoptic cold front was not situated far behind - roughly from Macon to Panama City - but there was a distinct gap between the remnant low and the cold front. Aloft, a subtle but potent upper level PV anomaly was moving east near the mouth of the Mississippi River. Linear extrapolation and the latest RAP runs push the upper level wave into the western part of our area closer to 00 UTC. The approach of stronger upper level forcing from the west yet to arrive, as diagnosed well by the previous shift, should be able to generate some surface response. Even some minor pressure falls would be sufficient to temporarily delay or stall the eastward motion of the cold front. The result will be a fairly deep deformation zone (900-500mb) over the area that will be very slow to pivot east today. This should help maintain sufficient forcing for continued cloud cover and showers through the day - particularly in the eastern half of our area, and especially when you consider the 2.04" PWAT on the morning sounding from our office (close to +2 std. deviations above normal, or about 175% of normal). Therefore, high PoPs and cloud cover were maintained over the eastern portions of our area. High temperatures were adjusted to fit closer to raw model guidance, and in particular the average of the last few runs of the HRRR. This yields upper 70s in most locations, although some spots that see more regular breaks of sun could reach 80-82 degrees. && .SHORT TERM [Tonight Through Wednesday]... As the primary upper trough lifts northeast into Canada tonight, a southern shortwave over the Gulf of Mexico will slide east and cutoff a weak upper low over north florida. This upper low will lift slowly northward into the central Appalachians through Wednesday. At the surface, the area of low pressure currently over the northeastern Gulf will move slowly across northeast tonight into Tuesday, before moving northeastward off the coast Tuesday night into Wednesday. High pressure, centered over New England will nose southward to the Gulf Coast behind the surface low. This evolution will prevent low-level dry air from pushing into much of the region over the next few days, keeping plenty of clouds in place. In addition, showers are expected to develop within the cool northeasterly flow in the wake of the surface low, aided by the upper level low. Thus, for Tuesday, have lowered high temperatures and raised PoPs, especially for southwest and south central Georgia. The support for rain should diminish into Wednesday. However, the low-level moisture will be slow to scour out, with low clouds and cooler temperatures lingering. && .LONG TERM [Wednesday Night through Sunday]... In general there is good model agreement for this period with quiet weather and temperatures near or slightly below climatology. Expect dry conditions with highs in the low to mid 80s and overnight lows in the mid 50s to mid 60s. && .AVIATION [through 12 UTC Tuesday]... ---Updated at 10:00 AM EDT--- A patch of IFR CIGS was persisting in portions of SE Alabama and the western Florida Panhandle as of 14 UTC, roughly centered on DHN. ECP was on the southern periphery. This could linger until around 17-18 UTC, when guidance suggests clouds will lift and scatter out. These TAFs will be amended to account for that cloud layer. Elsewhere, MVFR ceilings and periodic -SHRA will prevail at ABY, TLH, VLD. && .MARINE... ---Updated at 10:00 AM EDT--- The remnant low has shifted into the section of the coastal waters east of Apalachicola. Observations and the consensus of all models is that winds will be weaker immediately near the low, and be stronger on the back side of the low (and behind a nearby cold front). With this in mind, we will be converting the eastern waters to a SCEC headline for some patches of 15-20 knot winds today, and more widespread 15-20 knot winds tonight. The western waters will have a Small Craft Advisory through 06 UTC for the stronger north winds behind the low. && .FIRE WEATHER... Relative humidity values will remain above critical levels for the foreseeable future. Thus, hazardous fire weather conditions are not anticipated. && .HYDROLOGY... While localized heavy rain will be possible through this afternoon, primarily across the eastern half of the area, most areas will see less than an inch. This should have little impact on area rivers and streams. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 79 65 82 61 80 / 60 30 30 10 10 Panama City 79 64 82 64 81 / 30 10 10 10 10 Dothan 77 59 79 58 78 / 50 20 30 10 10 Albany 78 64 75 58 75 /100 30 40 20 10 Valdosta 80 66 78 59 75 / 70 40 50 20 10 Cross City 80 67 85 62 82 / 70 40 30 10 10 Apalachicola 82 67 80 65 80 / 60 10 20 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...SMALL CRAFT ADVISORY until 2 AM EDT Tuesday morning for coastal waters west of Apalachicola, out to 60 NM. && $$ NEAR TERM...Lamers SHORT TERM...Camp LONG TERM...Hollingsworth AVIATION...Lamers MARINE...Lamers FIRE WEATHER...Harrigan HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
728 AM EDT MON OCT 7 2013 .SYNOPSIS... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL CROSS LATE TONIGHT. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THIS FRONT AND MOVE NEAR THE AREA TUESDAY AND WEDNESDAY...PRODUCING WIDESPREAD RAIN AND MUCH COOLER TEMPERATURES. A DRYING AND WARMING TREND WILL BEGIN LATE IN THE WEEK AS HIGH PRESSURE BUILDS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 730 AM MONDAY...RADAR TRENDS AND THE LATEST HRRR MODEL SUGGESTS THE CONVEYOR BELT OF SHOWERS WILL CONTINUE MOVING ACROSS EASTERN SOUTH CAROLINA AND THE LUMBERTON AREA FOR AT LEAST THE REMAINDER OF THE MORNING HOURS...GRADUALLY SHIFTING EAST TO INCLUDE THE MYRTLE BEACH-WHITEVILLE-ELIZABETHTOWN CORRIDOR BEFORE NOON. UNLESS ISOLATED CELLS DEVELOP OUT AHEAD OF THE MAIN LINE IT COULD BE AS LATE AS 4 PM BEFORE WILMINGTON GETS IN ON THE ACTION. NO CHANGES HAVE BEEN MADE TO TEMPERATURES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A STREAM OF SHOWERS ORIGINATING FROM THE GULF STREAM WATERS OFF THE GA/FL COAST CONTINUES TO MOVE NORTH INTO EASTERN SC EARLY THIS MORNING. SYNOPTIC MODELS 24 HOURS AGO WERE NOT ABLE TO CAPTURE THIS FEATURE...BUT RECENT HIGH-RESOLUTION MODELS LIKE THE HRRR AND NSSL WRF SEE IT WELL AND INDICATE THE "STREAMER" WILL CONTINUE THROUGH THE MORNING HOURS WITH SIGNIFICANT RAINFALL TOTALS POSSIBLE ACROSS EASTERN SOUTH CAROLINA. STRONG UPPER LEVEL LOW PRESSURE ACROSS THE SOUTHERN GREAT LAKES IS THE SAME SYSTEM RESPONSIBLE FOR THE RECORD-BREAKING EARLY SNOW ACROSS WESTERN SOUTH DAKOTA A COUPLE DAYS AGO. THIS UPPER SYSTEM WILL LIFT NORTHEAST...WHILE A VORTICITY MAXIMUM AT THE BASE OF THE UPPER TROUGH ALONG THE GULF COAST SLOWS AND BEGINS TO FORM A CLOSED LOW LATE TONIGHT. THE SURFACE PATTERN MIRRORS THE 500 MB CHART WITH AN EASTWARD-MOVING COLD FRONT LOCATED JUST AHEAD OF THE UPPER TROUGH. THIS FRONT WILL SLOW ITS PROGRESS AS SURFACE LOW PRESSURES DEVELOPS IN IN THE FLORIDA PANHANDLE. SHOWER AND T-STORM CHANCES ARE VERY HIGH TODAY...PROBABLY AT LEAST 90 PERCENT COVERAGE ACROSS THE EASTERN CAROLINAS. THIS MORNING`S HEAVY BAND OF SHOWERS ACROSS EASTERN SOUTH CAROLINA SHOULD SOAK THE PEE DEE AND INTERSTATE 95 CORRIDOR THROUGH MID-MORNING...SHIFTING EAST FROM MYRTLE BEACH THROUGH WHITEVILLE AND ELIZABETHTOWN BY NOON...THEN FINALLY REACHING THE CAPE FEAR AREA INCLUDING WILMINGTON BY THE MID-AFTERNOON HOURS. FROM A BROAD-SCALE PERSPECTIVE MANY AREAS SHOULD SEE TWO-THIRDS TO ONE INCH OF RAIN TODAY...BUT WITH TRAINING CONVECTION UNDOUBTEDLY A FEW SPOTS WILL RECEIVE 2-3 INCHES OR MORE. SEVERE WEATHER POTENTIAL IS NOT ZERO...BUT IS LESS THAN EXPECTED YESTERDAY DUE TO WEAKENING LOW-LEVEL WIND FIELDS AND OVERALL MODEST INSTABILITY. IN FACT IT APPEARS ISOLATED FLOODING MAY BECOME A LARGER FACTOR TO CONTEND WITH THAN SEVERE WEATHER. SHOULD A THUNDERSTORM BECOME SEVERE TODAY...WET MICROBURSTS APPEAR TO BE THE MOST SIGNIFICANT THREAT. TONIGHT THE PRESSURE GRADIENT BETWEEN THE LOW OVER NORTHERN FLORIDA AND HIGH PRESSURE STRENGTHENING OVER PENNSYLVANIA SHOULD PRODUCE A NORTHERLY SURGE THAT WILL REACH OUR AREA A FEW HOURS BEFORE SUNRISE. THIS SHALLOW COLD AIRMASS WILL UNDERCUT THE OTHERWISE WARM AND HUMID AIR PRESENT...PRODUCING GUSTY WINDS AND SUDDENLY FALLING TEMPERATURES. PRECIPITATION CHANCES WILL CONTINUE AS WELL... ESPECIALLY ALONG THE COAST...BUT ISENTROPIC PROCESSES WILL BECOME MORE DOMINANT WITH TIME AS INSTABILITY WANES AND VEERING LOW LEVEL WINDS ADVECT ATLANTIC MOISTURE BACK ONSHORE. POPS TONIGHT RANGE FROM 80 PERCENT ALONG THE COAST TO 60 PERCENT IN FLORENCE AND DARLINGTON. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...SLOW MOVING UPPER LOW WILL EJECT OUT OF THE GULF OF MEXICO AND DRIFT NORTHEAST THROUGH THE PERIOD...SPAWNING A WAVE OF LOW PRESSURE ALONG A COLD FRONT STALLED ON THE COAST. STRONG VORT MAX ACROSS SOUTHEAST TEXAS WILL MOVE INTO THE GULF AND THEN DRIFT NORTHEAST OVERHEAD THE CAROLINAS TUESDAY AND WEDNESDAY. THIS SPAWNS A SURFACE WAVE ALONG A COLD FRONT WHICH WILL BE STALLED RIGHT ON THE COAST...AND WILL KEEP UNSETTLED WEATHER THROUGH THE PERIOD. GUIDANCE IS IN GOOD AGREEMENT THAT BOTH TUESDAY AND WEDNESDAY WILL BE WET...A SIGNIFICANT CHANGE FROM MODELS LAST NIGHT. AS THE FRONT STALLS JUST OFFSHORE...ABUNDANT TROPICAL MOISTURE REMAINS IN PLACE. THIS SERVES AS THE FUEL FOR PERIODS OF MDT/HVY RAIN TUE AND WED AS THE UPPER LOW MOVES OVERHEAD. ADDITIONALLY...ISENTROPIC LIFT OVER THE DEVELOPING WEDGE-HIGH PRESSURE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA. WPC IS SHOWING WIDESPREAD 1-2 INCHES OF QPF...MOST ACROSS THE CAPE FEAR REGION TUE/WED. THIS MAY BE A BIT HIGH...BUT CERTAINLY SHOWS THE POTENTIAL WITHIN THE TROPICAL MOISTURE PLUME. IN ADDITION TO THE UNSETTLED WEATHER...TEMPS WILL BE WELL BELOW NORMAL BOTH TUE AND WED THANKS TO THE WEDGE HIGH PRESSURE AND CLOUDS/RAIN. STRONG LOW LVL CAA DEVELOPS EARLY TUESDAY...AND HAVE SHOWN AN ATYPICAL DIURNAL CURVE WITH MAX TEMPS BEING REACHED FIRST THING TUESDAY MORNING...BEFORE FALLING THROUGH THE DAY. HIGHS ON TUESDAY WILL REACH ONLY THE MID/UPR 60S...AGAIN...EARLY IN THE DAY...AND THEN FALL INTO THE LOW 60S/UPR 50S BY EVE. THIS COMBINES WITH STRONG NE WINDS WHICH MAY GUST TO 30 MPH...AND TUESDAY WILL FEEL MORE LIKE NOVEMBER IN SEATTLE THAN OCTOBER IN WILMINGTON! LOWS TUESDAY NIGHT WILL SHOW VERY LITTLE DIURNAL RANGE...DROPPING ONLY INTO THE MID 50S INLAND...AROUND 60 AT THE COAST. LITTLE IMPROVEMENT WEDNESDAY...BUT ANY IMPROVEMENT WILL BE WELCOMED AFTER TUESDAY! CLOUDS AND RAIN PERSISTING WILL AGAIN LIMIT WARMING IN THE WEDGE SETUP...AND HIGHS WILL PEAK IN THE UPR 60S INLAND...LOW 70S NEAR THE COAST. LOWS WED NIGHT WILL BE SIMILAR TO TUESDAY NIGHT...UPR 50S TO LOW 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...ONE MORE UNSETTLED DAY THURSDAY AS VERY SLOW MOVING UPPER LOW AND SURFACE WAVE WILL FINALLY MOVE OFF TO THE NORTHEAST AND ALLOW FOR DRYING ACROSS THE AREA. GUIDANCE IN DISAGREEMENT AS TO HOW LONG IT WILL TAKE FOR DRYING TO OCCUR...BUT WITH UPPER LOW EMBEDDED WITHIN THE 5H RIDGE...THUS MOVING VERY SLOWLY...WILL LEAN ON THE SLOWER SOLUTION AND KEEP SCHC POP ACROSS NE ZONES EARLY THURSDAY BEFORE THE ENTIRE AREA DRIES OUT. BEYOND THURSDAY...HEIGHTS GRADUALLY RISE AND THE WEDGE SLOWLY BREAKS DOWN...ALLOWING FOR MUCH MORE SUNSHINE AND TEMPS WARMING BACK TOWARDS CLIMO OR ABOVE BY THE WKND. GFS/EURO/CMC STILL DEPICT A SECONDARY AREA OF LOW PRESSURE DEVELOPING WELL OFFSHORE AND THEN RETROGRADING BACK TO THE SW SAT/SUN TOWARDS THE COAST. WHILE THIS HAS BEEN A PERSISTENT FEATURE IN THE EXTENDED GUIDANCE...LITTLE AGREEMENT IN SPECIFIC PLACEMENT AND WHETHER ANY IMPACTS WILL BE FELT LOCALLY. WILL KEEP INHERITED SILENT POP FOR D6/D7 WITH TEMPS RIGHT AROUND NORMAL FOR MID-OCTOBER. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 12Z...SHOWERS CURRENTLY AFFECTING KFLO/KLBT WITH SUB-VFR FLIGHT CONDITIONS WILL GRADUALLY SPREAD EAST INTO THE COASTAL TERMINALS TODAY. THIS MORNING INTO THE AFTERNOON MVFR WILL BE LIKELY AT KFLO/KLBT...WITH TEMPO IFR IN MODERATE RAINFALL. THIS MORNING COASTAL TERMINALS SHOULD REMAIN GENERALLY VFR WITH TEMPO MVFR CIGS...WITH MVFR BECOMING MORE LIKELY TOWARDS LATE MORNING AS THE SHOWERS SHIFT EAST. AN APPROACHING COLD FRONT WILL PROVIDE ENOUGH LIFT TODAY ALONG WITH ENOUGH INSTABILITY TO PRODUCE AT LEAST ISOLATED T-STORMS. WILL CONTINUE VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. THERE IS INCREASING CONFIDENCE OF PREDOMINATE IFR AT KFLO/KLBT AFTER 06Z. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 730 AM MONDAY...SEAS HAVE BUILT TO 5 FT AT ALL THREE BUOYS STILL REPORTING IN THE CAPE FEAR AREA. WIND SPEEDS ARE ABOUT AS STRONG AS THEY ARE GOING TO GET...17 TO 20 KNOTS CURRENTLY...AND A DIMINISHING TREND IS STILL EXPECTED TO DEVELOP THIS AFTERNOON. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... A NORTH-TO-SOUTH ORIENTED COLD FRONT JUST ENTERING THE APPALACHIANS WILL MOVE EASTWARD TODAY...DECELERATING AS IT APPROACHES THE COAST TONIGHT. SOUTH-SOUTHEAST WINDS 15-20 KNOTS THIS MORNING SHOULD DIMINISH THIS AFTERNOON. LOW PRESSURE DEVELOPING ALONG THE FRONT NEAR THE FLORIDA PANHANDLE WILL BECOME OUR DOMINANT WEATHER FEATURE TONIGHT. THE INCREASING PRESSURE GRADIENT BETWEEN THIS LOW AND STRENGTHENING HIGH PRESSURE OVER PENNSYLVANIA WILL LEAD TO INCREASING WIND SPEEDS LATE TONIGHT. A SURGE IS EXPECTED TO DEVELOP A FEW HOURS BEFORE DAYBREAK...WITH WINDS TURNING NORTH-NORTHEAST AND INCREASING TO 15-20 KT. SEAS CURRENTLY RANGE FROM 5 FT OUT AT THE FRYING PAN SHOALS BUOY...TO 3-4 FT CLOSER TO SHORE. STEADY ONSHORE WINDS THIS MORNING SHOULD BRING 5-FOOTERS INTO THE 10-20 MILE WATERS...AND AN EXERCISE CAUTION HEADLINE WILL BE APPENDED TO THE FORECAST THROUGH EARLY AFTERNOON. DIMINISHING WINDS THIS AFTERNOON WILL ALLOW SEAS TO SUBSIDE...BUT LOOK FOR BUILDING SEAS AGAIN VERY LATE TONIGHT IN THE NORTHERLY SURGE. SHOWERS AND THUNDERSTORMS CURRENTLY ACROSS EASTERN SOUTH CAROLINA WILL IMPACT THE SC COASTAL WATERS THIS MORNING. GUSTY WINDS AND REDUCED VISIBILITY IN HEAVY RAINFALL ARE EXPECTED. THIS ACTIVITY WILL MOVE EAST AND AFFECT THE NC WATERS THIS AFTERNOON. PRECIPITATION SHOULD BECOME LESS THUNDERY TONIGHT BUT SHOULD OTHERWISE CONTINUE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...STRONG NE WINDS WILL PERSIST THROUGH THE PERIOD AS THREE FEATURES COMBINE TO CREATE POOR MARINE CONDITIONS INTO MID-WEEK. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT STALLED JUST OFFSHORE...ENHANCING THE ALREADY PINCHED GRADIENT DUE TO A WEDGE OF HIGH PRESSURE FORMING DOWN THE COAST. THIS CREATES GUSTY NE WINDS TUESDAY AND WEDNESDAY...WITH SPEEDS OF 15-25 KTS TUESDAY...DROPPING SLIGHTLY TO 15-20 KTS ON WEDNESDAY. GUSTS TO 30 KTS ARE POSSIBLE...ESPECIALLY ON TUESDAY. THIS CREATES SHORT-PERIOD AND STEEP WIND WAVES REACHING 4-7 FT TUESDAY...BEFORE FALLING SLOWLY TO 3-5 FT BY WEDNESDAY EVE. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR ALL OF TUESDAY AND PARTS OF WEDNESDAY BEFORE CONDITIONS SLOWLY BEGIN TO IMPROVE LATE IN THE PERIOD. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...GUSTY N/NE WINDS TO START THE PERIOD WILL GRADUALLY EASE BY THE END OF THE WEEK AS HIGH PRESSURE WEDGE BEGINS TO BREAK DOWN JUST INLAND FROM THE WATERS. TIGHT GRADIENT THURSDAY KEEPS N/NE WINDS AT 15-20 KTS...BUT THIS WILL WEAKEN ON FRIDAY...HELPING WINDS TO FALL TO AROUND 10 KTS AND BACK MORE TO THE NORTH. WAVE HEIGHTS INITIALLY WILL BE 3-5 FT AND A SCEC MAY BE REQUIRED...BUT THESE WILL FALL QUICKLY ON FRIDAY TO 2-3 FT THANKS TO THE DECREASED WINDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...MRR MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1017 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10AM EDT MONDAY...BROKEN LINE OF CONVECTION CONTINUES TO PUSH EAST OF THE I77 CORRIDOR INTO CENTRAL NC. A FEW LIGHT SHOWERS WILL BE A POSSIBILITY OVER THE NEXT FEW HOURS BEHIND THE LEADING LINE. THEREFORE KEPT CHANCE POPS THROUGH MIDDAY OUTSIDE OF THE MOUNTAINS. OTHERWISE...DECIDED TO GO AHEAD AND LOWER POPS ACROSS THE HIGHER TERRAIN AS THE FRONT PUSHES THROUGH ADVECTING IN MUCH MORE STABLE AIR. SKY CONDITIONS WILL SLOWLY IMPROVE ACROSS THE MOUNTAINS THROUGH THE DAY AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT. ELSEWHERE...CLOUDS WILL PERSIST THROUGH THE AFTERNOON HOURS AND INTO MONDAY EVENING AS DEEP LAYER MOISTURE PREVAILS AHEAD OF THE FRONT. OTHER THAN THE ABOVE MENTIONED POP/WX/SKY ADJUSTMENTS...NO OTHER CHANGES WERE MADE TO THE FCST AT THIS TIME. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-14Z KCLT HIGH 94% HIGH 90% HIGH 100% HIGH 100% KGSP HIGH 82% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 82% HIGH 100% HIGH 100% HIGH 94% KHKY HIGH 80% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 91% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 91% HIGH 98% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...CDG/WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
806 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 8AM EDT MONDAY...LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE EASTWARD ACROSS THE COVERAGE AREA WITH THE HEAVIEST CONVECTION BEING ALONG A LINE NEAR THE I77 CORRIDOR. THIS LINE WILL MOVE INTO CHARLOTTE METRO WITHIN THE HOUR. THE MAIN THREATS AT THIS TIME ARE GUSTY WINDS AND HEAVY RAINFALL. MEANWHILE TO THE WEST...LEADING EDGE OF THE COLD FRONT IS PUSHING THROUGH THE MOUNTAINS AND WILL CONTINUE MOVING EASTWARD THROUGH THE DAY. ADJUSTED EXTREME NEAR TERM POPS TO REFLECT LATEST RADAR TRENDS AND LEFT THE REMAINDER OF THE FORECAST AS IS. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 12-18Z 18-24Z 00-06Z 06-12Z KCLT HIGH 100% HIGH 80% HIGH 100% HIGH 100% KGSP MED 79% HIGH 94% HIGH 100% HIGH 100% KAVL MED 75% HIGH 100% HIGH 100% HIGH 100% KHKY MED 67% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 83% HIGH 96% HIGH 100% HIGH 100% KAND MED 79% HIGH 95% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...CDG/WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
734 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 11-17Z 17-23Z 23-05Z 05-11Z KCLT HIGH 100% HIGH 85% HIGH 97% HIGH 100% KGSP MED 77% HIGH 92% HIGH 100% HIGH 100% KAVL MED 75% HIGH 98% HIGH 100% HIGH 100% KHKY MED 61% HIGH 98% HIGH 100% HIGH 100% KGMU HIGH 85% HIGH 92% HIGH 100% HIGH 100% KAND MED 79% HIGH 94% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS TAUNTON MA
613 PM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING ACCOMPANIED BY BRIEF HEAVY RAIN...GUSTY WINDS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL RESULT IN DRY AND SEASONABLE WEATHER TUE INTO THU AFTERNOON. LOW PRESSURE MAY BRING A BIT OF RAIN AT TIMES THU NIGHT INTO EARLY NEXT WEEK...BUT ONLY IF THE SYSTEM TRACKS FAR ENOUGH NORTH. THERE IS VERY LOW FORECAST CONFIDENCE LATE IN THE WEEK INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 615 PM UPDATE... ***SEVERE THUNDERSTORM WATCH THROUGH 10 PM FOR SOUTHERN NH...WESTERN/CENTRAL MA AS WELL AS NORTHEAST MA AND NORTHERN CT*** NARROW LINE OF HEAVY SHOWERS ALONG WITH POCKETS OF STRONG WIND GUSTS WERE MOVING ACROSS SOUTHWEST NH/WESTERN MA AND NORTHERN CT EARLY THIS EVENING. HRRR MODEL HAS HAD A PRETTY GOOD HANDLE ON THIS ACTIVITY AND EXPECT IT TO CONTINUE TO MOVE EAST OVER THE NEXT FEW HOURS. THE BULK OF THE ACTIVITY SHOULD EXIT THE COASTLINE BY 10 OR 11 PM...ALTHOUGH SHOULD LINGER A BIT LONGER ACROSS THE SOUTHEAST NEW ENGLAND COAST. THERE ALSO COULD BE A FEW LIGHTER SHOWERS LINGERING BEHIND THE MAIN LINE. THIS IS A CLASSIC HIGH SHEAR BUT VERY LOW CAPE ENVIRONMENT. IN FACT...HAVEN/T EVEN SEEN ANY CLOUD TO GROUND LIGHTNING RECENTLY. MAY SEE AN ISOLATED LIGHTNING STRIKE IN THE NEXT HOUR OR TWO...BUT CERTAINLY NOT MUCH. REGARDLESS...WITH THE VERY STRONG JET DYNAMICS AND FULLY LEAFED TREES WE HAVE BEEN GETTING A LOT OF TREE DAMAGE REPORTS. WE DID EXTEND SEVERE THUNDERSTORM WATCH INTO NORTHEAST MA THROUGH 10 PM WHERE BEST LOW LEVEL JET MOVES INTO OVER THE NEXT FEW HOURS. ALSO...THE REST OF THE REGION IS COVERED IN A WIND ADVISORY EXCEPT FOR THE SOUTH COAST. MANY LOCATIONS MAY REMAIN BELOW WIND ADVISORY CRITERIA...BUT GIVEN FULLY LEAFED TREES INCREASED RISK FOR DAMAGE WILL CONTINUE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... LARGE HIGH PRES BUILDS E ACROSS SNE BRINGING SUNNY SKIES AND SEASONABLY MILD TEMPS. COLUMN IS QUITE DRY SO EVEN CU WILL BE LIMITED. HIGH TEMPS WILL REACH MID/UPPER 60S...COOLER HIGHER TERRAIN. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * DRY AND SEASONABLE WEATHER LIKELY WED AND MOST OF THU * A BIT OF RAIN POSSIBLE AT TIMES THU NIGHT INTO EARLY NEXT WEEK * MAY END UP COMPLETELY DRY IF STORM STAYS SOUTH DETAILS... TUESDAY NIGHT... HIGH PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND AND RESULT IN A CHILLY NIGHT. LOW TEMPS WILL FALL MAINLY INTO THE 30S...TO THE MIDDLE 40S ACROSS MOST AREAS. WE MAY NEED TO CONSIDER FROST ADVISORIES FOR PORTIONS OF SOUTHWEST NH/NORTHWEST MA...IF WINDS ARE ABLE TO DECOUPLE WHICH REMAINS UNCERTAIN AT THIS POINT. WEDNESDAY AND THURSDAY... LARGE HIGH PRESSURE SHOULD KEEP OUR WEATHER DRY WEDNESDAY INTO MOST OF THURSDAY AFTERNOON. MODEL CROSS SECTIONS DO INDICATE THAT WE MAY SEE SOME HIGH CLOUDINESS MOVE IN FROM A LOW PRESSURE SYSTEM OVER THE MID ATLANTIC. THIS SHOULD ALSO RESULT IN ONSHORE FLOW KEEPING HIGH MAINLY IN THE 60S...ALTHOUGH A FEW LOWER 70S MAY BE POSSIBLE ACROSS THE INTERIOR. THURSDAY NIGHT THROUGH MONDAY... FORECAST CONFIDENCE REMAINS VERY LOW OVER THIS TIME PERIOD. HIGH PRESSURE WILL REMAIN LOCATED ACROSS THE CANADIAN MARITIMES WITH A LOW MEANDERING SOMEWHERE TO OUR SOUTH. DEPENDING ON HOW FAR NORTH THIS LOW PRESSURE SYSTEM GETS WILL DETERMINE IF WE END UP GETTING A PERIOD OR TWO OF RAIN. BIGGER THREAT FOR A SUSTAINED PERIOD OF WET WEATHER WILL BE TO OUR SOUTH...BUT CAN/T RULE OUT SOME RAIN IN OUR REGION WITH BEST CHANCE IN THE SOUTHERN ZONES. THE MODELS AND ENSEMBLES HAVE SHOWN DIFFERING SOLUTIONS AND VERY POOR RUN TO RUN CONSISTENCY. WILL GENERALLY RUN WITH 20 TO 30 POPS TO COVER THIS POTENTIAL...WITH THE HIGHER POPS IN OUR SOUTHERN ZONES. BEST CHANCE FOR A BIT OF RAIN MAY COME THU NIGHT INTO FRI THEN AGAIN LATER SUN INTO MON. ITS ALSO POSSIBLE ALL THE RAIN REMAINS TO OUR SOUTH OVER THIS TIME...JUST TOO UNCERTAIN TO SAY MUCH MORE AT THIS POINT. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE IN TRENDS LOWER CONFIDENCE IN TIMING. CONDITIONS HAVE TEMPORARILY IMPROVED TO MVFR/VFR AS WARM FRONT HAS LIFTED TO THE NORTH. INCREASING S WINDS WILL DEVELOP WITH GUSTS TO 35 KT POSSIBLE THROUGH THE REST OF THE AFTERNOON...ESPECIALLY AWAY FROM S COAST. EXPECT IFR TO REDEVELOP LATER THIS AFTERNOON AND EVENING AS LINE OF SHOWERS/TSTMS MOVE THROUGH. BRIEF HEAVY RAIN AND STRONG WINDS WILL LIKELY ACCOMPANY THIS LINE OF CONVECTION...ESPECIALLY CT VALLEY THEN GRADUALLY WEAKEN AS IT MOVES TO THE COASTAL PLAIN. IMPROVING CONDITIONS TO VFR FROM WEST TO EAST 03-08Z. VFR TUESDAY. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR EXPECTED WITH A BRIEF PERIOD OF IFR POSSIBLE THIS EVENING. BRIEF HEAVY RAIN POSSIBLE 23-03Z. WIND GUSTS TO 35 KT THROUGH 00Z. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR WITH A BRIEF PERIOD OF IFR POSSIBLE LATE AFTERNOON AND EARLY EVENING. BRIEF HEAVY RAIN 21-00Z. WIND GUSTS TO 35 KT POSSIBLE THIS AFTERNOON. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... TUE NIGHT THROUGH THURSDAY...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. THURSDAY NIGHT THROUGH SATURDAY...LOW CONFIDENCE. SOME MVFR TO EVEN IFR CONDITIONS ARE POSSIBLE AT TIMES IF A MID ATLANTIC LOW MAKES IT FAR ENOUGH NORTH ALLOWING FOR SOME RAIN. BEST CHANCE WOULD BE THU NIGHT/FRI. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...MODERATE CONFIDENCE. 520 PM UPDATE... ONLY CHANGE WAS TO UPGRADE BOSTON HARBOR TO A GALE WARNING THROUGH 9 PM WHERE AS BEST LOW LEVEL JET MOVES OVER THE REGION. TEMPS ARE ALSO THE WARMEST IN NORTHEAST MA...SO BETTER CHANCE OF MIXING TO THE GROUND. PREVIOUS DISCUSSION: LOW PROB FOR BRIEF SOUTHERLY GALES OVER EASTERN WATERS THROUGH EARLY EVENING AS THE LOW LEVEL JET PEAKS ACROSS THE WATERS. BUT LOW LEVEL INVERSION WILL LIMIT STRONGEST WINDS FROM MIXING DOWN SO IT IS MORE LIKELY THAT GUSTS WILL REMAIN IN SCA RANGE. BEST CHANCE FOR MARGINAL GALES MAY ACTUALLY OCCUR IN BOS HARBOR THROUGH 9 PM. WINDS SHIFT TO NW AND DIMINISH OVERNIGHT WITH SUBSIDING SEAS. NORTHERLY WINDS BELOW SCA TUESDAY. SEAS MOSTLY BELOW SCA AS WELL BUT 5 FT SEAS MAY LINGER OVER OUTER SE WATERS. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... HIGH CONFIDENCE IN OVERALL WIND DIRECTION....BUT LOWER CONFIDENCE IN WIND SPEEDS AND TIMING. LOW PRESSURE TO THE SOUTH OF OUR WATERS WITH HIGH PRESSURE OVER THE CANADIAN MARITIMES WILL RESULT IN A PERSISTENT EAST TO NORTHEAST FLOW OF AIR MOST OF THE TIME. PERIODS OF 20 TO 25 KNOT NORTHEAST WIND GUSTS ARE EXPECTED FOR MUCH OF THE PERIOD. WINDS MAY END UP A BIT STRONGER FOR A TIME...DEPENDING ON HOW FAR NORTH MID ATLANTIC LOW PRESSURE SYSTEM MAKES IT. IT DOES APPEAR THAT THE BEST CHANCE FOR THE STRONGER WINDS WILL BE ACROSS OUR SOUTHERN ATLANTIC WATERS. SCA SEAS ARE ALSO LIKELY FOR MUCH OF THE TIME ACROSS OUR SOUTHERN AND SOUTHEAST ATLANTIC WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ002>019-026. NH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NHZ011-012-015. RI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR RIZ001>004. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ231>235-237- 254>256. GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR ANZ230-250-251. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ236. && $$ SYNOPSIS...KJC/FRANK NEAR TERM...FRANK SHORT TERM...KJC LONG TERM...FRANK AVIATION...KJC/FRANK MARINE...KJC/FRANK
AREA FORECAST DISCUSSION
NWS ALBANY NY
249 PM EDT MON OCT 7 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL BRIEFLY BE OVER THE REGION THIS AFTERNOON. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH HEAVY RAIN SHOWERS...GUSTY WINDS AND POSSIBLE STRONG TO SEVERE THUNDERSTORMS. BY TUESDAY...A DRIER...COOLER AND LESS HUMID AIR MASS WILL RETURN FOR MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 248 PM EDT... TORNADO WATCH 543 REMAINS IN EFFECT UNTIL 5 PM EDT FOR ERN NY AND NOW INCLUDES ALL OF WESTERN NEW ENGLAND. IT HAS BEEN EXPANDED TO INCLUDE SRN VT...WRN MA...AND NW CT. THE WIND ADVISORY REMAINS UP UNTIL 8 PM FOR ALL OF ERN NY AND WRN NEW ENGLAND. A COLD FRONT CONTINUES TO MOVE ACROSS ERN NY TOWARDS THE HUDSON RIVER VALLEY. A HIGH SHEAR AND LOW CAPE ENVIRONMENT IS IN PLACE ACROSS THE ALY FCST AREA WITH THE LATEST SPC MESO PAGE SHOWING INSTABILITY VALUES LESS THAN 500 J/KG ACROSS MOST OF THE AREA...WITH THE HIGHEST AMOUNTS ACROSS THE EXTREME SRN TIER. THE 0-6 KM BULK SHEAR VALUES HAVE INCREASED TO 40-65 KTS...WITH THE LOW-LEVEL 0-1 KM SHEAR VALUES ALSO VERY IMPRESSIVE IN THE 30-45 KT RANGE...WITH THE HIGHEST VALUES OVER THE NRN TIER. THE WIND ADVISORY LOOKS GOOD...AND SOME BOWING SEGMENTS WITH THE LINE ECHO WAVE PATTERN /LEWP/ UPSTREAM HAVE PRODUCED SOME ISOLD/SPORADIC WIND DAMAGE UPSTREAM OVER W-CNTRL NY AND PA. THE UPPER TROUGH IS TURNING NEGATIVELY TILTED...AND THERE IS A THREAT FOR SOME OF THIS STRONG MOMENTUM TRANSFERRED DOWN FROM H925-H850. THE PAUCITY OF INSTABILITY AND WEAK MID LEVEL LAPSE RATES HAVE INHIBITED CG STRIKES. THERE IS A STRIKE HERE OR THERE UPSTREAM. DUE TO THE DYNAMICALLY FORCED LEWP... THE POTENTIAL FOR SOME NEAR THUNDERLESS OR THUNDERLESS SEVERE STORMS WILL CONTINUE UNTIL LATE THIS PM. THE IMPACT PERIOD CONTINUES TO BE 1-5 PM FROM WEST TO EAST. THE LATEST 3-KM HRRR LINES UP WELL WITH THIS TIME FRAME. A BRIEF SPIN-UP TORNADO MAY BE POSSIBLE ALONG THE LEWP DUE TO THE STRONG LOW-LEVEL WIND SHEAR...DESPITE THE WEAK INSTABILITY. A TOR WARNING WAS ISSUED FOR PARTS OF HERKIMER...NW FULTON...AND SW HAMILTON COUNTY. SOME REPORTS OF WIND DAMAGE ARE COMING IN NEAR STRATFORD IN NW FULTON COUNTY. SEVERAL SVRS ARE BEING ISSUED FOR THE ALY FCST AREA AT THIS TIME. THE NARROW COLD FRONTAL RAIN BAND /SHALLOW LINE OF CONVECTION/ SHOULD BE EAST OF THE FCST AREA BY 6 PM. DESPITE THE CLOUD COVER...THE FCST AREA IN THE WARM SECTOR...HAS ALLOWED TEMPS TO REACH THE MID 60S TO M70S OVER THE REGION. TEMP FALLS IN THE WAKE OF THE COLD FRONT HAVE BEEN AS GREAT AS 15 DEGREES IN AN HOUR AT KSYR. A 46 KT GUST OCCURRED ABOUT 3 HOURS AGO. THE SHOWERS AND EMBEDDED TSTMS WILL LIKELY PRODUCE A PERIOD OF VERY HEAVY RAINFALL...FOR GENERALLY LESS THAN 2 HOURS. THE SHOWERS SHOULD GRADUALLY TAPER FROM W TO E AROUND OR JUST AFTER SUNSET. RAINFALL RATES COULD REACH A HALF AN INCH TO AN INCH AN HOUR DUE TO THE ANOMALOUS PWATS IN PLACE...AND THE STRONG CONVERGENCE WITH THE BOUNDARY. POPS...WX...AND TEMPS HAVE BEEN RETOOLED BASED ON THE OBSERVATIONAL TRENDS IN THE FCST GRIDS AND THE TOR WATCH EXPANSION. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... TONIGHT...ANY SHOWERS ACROSS EXTREME S/E AREAS SHOULD END BY 10 PM EDT. ADDITIONAL ISOLATED/SCATTERED SHOWERS COULD AFFECT THE WESTERN ADIRONDACKS LATER THIS EVENING OR OVERNIGHT...AS THE UPPER LEVEL COLD POOL PASSES ACROSS. OTHERWISE...EXPECT A PERIOD OF CLEARING IN MOST AREAS THIS EVENING...BUT ADDITIONAL CLOUDS MAY FORM ONCE AGAIN LATER TONIGHT AS THE COLD POOL PASSES BY...AND SOME LAKE MOISTURE SPREADS INTO THE REGION...ESP FOR AREAS NEAR AND N OF INTERSTATE 90. HAVE SIDED WITH THE SLIGHTLY WARMER MET MOS IN MOST AREAS. TUE-WED NT...GENERALLY DRY CONDITIONS ARE EXPECTED THROUGH THIS PERIOD. THE ONE CAVEAT COULD BE LINGERING CLOUDS ACROSS NORTHERN PORTIONS OF THE REGION TUESDAY...AS SOME LAKE MOISTURE BECOMES TRAPPED BENEATH A RAPIDLY LOWERING SUBSIDENCE INVERSION. FOR NOW HAVE INDICATED PARTLY TO MOSTLY SUNNY SKIES...BUT TRENDS WILL NEED TO BE WATCHED...AS MUCH MORE CLOUD COVER THAN CURRENTLY FORECAST COULD OCCUR FOR AREAS NORTH OF I-90. OTHERWISE...FOR TEMPS...GENERALLY SIDED WITH THE COOLER MET MPS FOR TUE MAXES...AND WENT A BIT WARMER THAN GUIDANCE FOR TUE NT MINS. SOME FROST POTENTIAL WILL EXIST IN PORTIONS OF THE UPPER HUDSON VALLEY...EASTERN CATSKILLS AND SOUTHERN VT...WHICH WILL BE ADDRESSED IN THE HWOALY. SOME HIGH AND MID LEVEL CLOUDS COULD SLOWLY EXPAND NORTH AND WEST INTO THE REGION LATE WED OR WED NT...DEPENDING ON THE TRACK AND EVOLUTION OF A POSSIBLE LOW PRESSURE SYSTEM DEVELOPING OFF THE SOUTHEAST COAST. && .LONG TERM /THURSDAY THROUGH MONDAY/... COMPLEX UPPER PATTERN SHOULD RESULT IN HIGHER UNCERTAINTY WITH DETAILS IN THE LONG RANGE FORECAST. IN THE THURSDAY THROUGH FRIDAY TIME FRAME...THERE IS A LOOSE CONSENSUS OF A COASTAL SYSTEM THAT DEVELOPS OFF THE MID ATLANTIC AS UPPER RIDGING BUILDS NORTH AND EAST INTO SOUTHEASTERN CANADA. MOST AREAS SHOULD BE UNDER THE INFLUENCE OF HIGH PRESSURE THURSDAY AND FRIDAY. EXCEPT...THERE COULD BE SOME CLOUDS AND ISOLATED SHOWERS IN THE SOUTHERN PARTS OF THE MID HUDSON VALLEY AND NW CT...WHERE THERE COULD BE SOME ONSHORE FLOW DUE TO THE PRESSURE GRADIENT DEVELOPING BETWEEN THE LOW LEVEL RIDGING OVER THE NORTHEASTERN U.S. AND THE COASTAL SYSTEM OFF THE MID ATLANTIC. HIGHS THURSDAY AND FRIDAY IN THE 60S TO NEAR 70. THE UPPER PATTERN POTENTIALLY BECOMES EVEN MORE COMPLICATED AS LOW LEVEL RIDGING BUILDS AND STRENGTHENS OVER SOUTHEASTERN CANADA AND EASTERN NEW ENGLAND AND THEN BUILDS WEST INTO NY SATURDAY AND SUNDAY. COOLER AIR ALSO BUILDS WEST INTO NY...POTENTIALLY RESULTING IN A COOLING TREND BOTH DAYS. THE UPPER RIDGING INTO SOUTHEASTERN CANADA MAY SUPPORT A SLIGHT NORTHWARD DRIFT TO THE UPPER FEATURE ASSOCIATED WITH THE LOW PRESSURE OFF THE EAST COAST...WITH MORE OF A PRESSURE GRADIENT AND ONSHORE FLOW IN SOUTHERN NY AND NW CT... DEPENDING ON EXACTLY HOW FAR NORTH THE COASTAL FEATURE CAN GET. WITH SUCH EXTREME SPREAD IN THE LONG RANGE GUIDANCE...GOING DRY FOR THE WEEKEND WITH HIGHS IN THE 60S...BUT COOLING A DEGREE OR TWO EACH DAY WITH THE COLD ADVECTION FROM THE EAST. MORE DETAILS WITH THIS COMPLICATED PATTERN SHOULD BE APPARENT TOWARD THE END OF THE WEEK...BUT AT LEAST THE RANGE OF POSSIBLE SENSIBLE WEATHER DOES NOT INCLUDE ANY HIGH IMPACT OR THREATENING WEATHER FOR OUR FORECAST AREA IN THE LONG RANGE...BUT SOME INCLEMENT WEATHER IS POSSIBLE DEPENDING ON HOW/IF THE COASTAL SYSTEM EVOLVES. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... COLD FRONT MAKING STEADY PROGRESS ACRS NYS AND EXPECT THE FRONT TO MOVE THROUGH THE TAF SITES IN THE 19Z-21Z TIME FRAME. GENERALLY EXPECT MVFR/IFR JUST AHEAD OF AND BEHIND THE FRONT WITH GUSTY WINDS AS WIND DIRECTION SHIFTS FROM S-SE AHEAD OF THE FRONT TO WESTERLY BEHIND THE FRONT. WIND GUSTS MAY BE AS HIGH AS 35 KTS WITH FROPA. ONCE FROPA HAS TAKEN PLACE EXPECT A FEW HOURS OF MVFR CONDITIONS WHICH WILL GIVE WAY TO VFR THIS EVENING. OVERNIGHT SKIES WILL BECOME SKC WELL AFTER MIDNIGHT AND FOG IS EPXECTED TO DEVELOP AT KGFL AND KPSF REDUCING CIGS AND VSBYS TO LIFR LATE AT NIGHT. ON TUESDAY EXPECT SKC CONDITIONS WITH NORTH TO NORTHWEST WINDS OF 8-10 KTS. OUTLOOK... LATE TONIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE ANTICIPATED OVER THE NEXT FEW DAYS. AFTER A WETTING DAY ON SUNDAY...ANOTHER WETTING DAY WITH MORE RAIN SHOWERS AND SCATTERED THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND EVENING. DRY WEATHER WILL RETURN TUESDAY THROUGH THE REMAINDER OF THE WEEK...WITH FULL RH RECOVERY EXPECTED EACH NIGHT WITH WIDESPREAD DEW FORMATION. && .HYDROLOGY... NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS FOR EARLY OCTOBER. A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND EVENING. MAINLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED THROUGH THIS MORNING WITH LIGHT PCPN AMOUNTS OF A TENTH OF AN INCH OR LESS. MUCH HEAVIER RAINFALL IS EXPECTED WITH THE COLD FRONT THIS AFTERNOON AND EVENING WITH THE POTENTIAL 0.75-1.5 INCH BASIN RAINFALL AVERAGES. ALL THE MODELS ARE NOW SHOWING THE COLD FRONT MOVING THROUGH QUICKLY...SO THERE APPEARS TO BE LITTLE IF ANY CHANCE THAT THE FRONTAL BOUNDARY AND THE HEAVY RAIN LINGERING OVER THE REGION AND PRODUCING MORE THAN TWO INCHES OF RAIN. DUE TO RECENT DRY CONDITIONS...FFG IS QUITE HIGH...AND THE COLD FRONT WILL BE MOVING FAST ENOUGH TO KEEP ANY HEAVY RAINFALL LIMITED TO JUST A FEW HOUR PERIOD. AS A RESULT...NO HYDROLOGIC PROBLEMS ARE ANTICIPATED OUTSIDE OF LOW LYING...POOR DRAINAGE...OR URBAN AREAS THAT TYPICALLY SEE WATER POND DURING HEAVY DOWNPOURS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY THROUGH THE REMAINDER OF THE WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013. NY...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...KL/WASULA NEAR TERM...WASULA SHORT TERM...KL LONG TERM...NAS AVIATION...11/NAS FIRE WEATHER...KL/GJM HYDROLOGY...KL/GJM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
151 PM EDT MON OCT 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS ARE EXPECTED TODAY ALONG WITH GUSTY SOUTHERLY WINDS. A BAND OF HEAVY SHOWERS...STRONG WINDS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON AND EVENING WITH A STRONG COLD FRONT. HIGH PRESSURE AND DRY SEASONABLE WEATHER OVERSPREADS SOUTHERN NEW ENGLAND TUE AND WED. A COASTAL LOW MAY BRING ANOTHER ROUND OF RAIN TO THE REGION LATER THIS WEEKEND AND POSSIBLY INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ** GUSTY WINDS AND HEAVY RAINFALL WITH A COLD FRONT LATE TODAY ** 145 PM UPDATE... QLCS ALONG THE COLD FRONT APPROACHING E NY AND NW NJ. CONVECTION HAS INTENSIFIED A BIT WITH LEWP STRUCTURE DEVELOPING WHICH IS A GOOD INDICATOR OF STRONG WINDS. MESOANALYSIS INDICATING SBCAPES OF 500 J/KG AHEAD OF THE LINE IN SNE. HRRR IS HANDLING THIS FAIRLY WELL AND BRINGS LINE INTO THE BERKSHIRES AND CT VALLEY 21-22Z THEN WEAKENS IT AS IT APPROACHES THE COASTAL PLAIN THIS EVENING. GREATEST THREAT FOR SEVERE WX WILL BE ACROSS W ZONES...PARTICULARLY THE BERKSHIRES AND CT VALLEY. 0-1KM SR HELICITY 300-400 M2/S2 ALONG AND JUST AHEAD OF THE LINE SO THE THREAT OF AN ISOLD TORNADO CANT BE RULED OUT...ESPECIALLY IF WE CAN GENERATE 500-1000 J/KG OF SFC BASED CAPE. PREVIOUS DISCUSSION... WARM FRONT STILL HUNG UP ACROSS THE INTERIOR FROM NEAR HFD TO OWD. TEMPS HAVE RISEN INTO THE UPPER 60S TO LOWER 70S WITH DEWPOINTS UPPER 60S S OF THE FRONT BUT TEMPS ARE STILL MOSTLY IN THE 50S TO THE NORTH IN THE INTERIOR. WE EXPECT THE FRONT WILL EVENTUALLY JUMP TO THE N AS THE LOW LEVEL INVERSION EVENTUALLY MIXES OUT WITH TEMPS INCREASING RAPIDLY INTO THE 70S THIS AFTERNOON IN THE INTERIOR. THE WARM TEMPS WILL HELP TO INCREASE MIXING IN THE LOW LEVELS. WITH DECENT LOW LEVEL JET ACROSS THE REGION...EXPECT INCREASING WINDS THIS AFTERNOON WITH SOUNDINGS SUPPORTING GUSTS TO 35-40 KT. EVEN IF THE WIND GUSTS FALL JUST SHORT OF ADVISORY CRITERIA...THE FULLY LEAVED TREES WILL ENHANCE THE POTENTIAL FOR MINOR WIND DAMAGE. AS A RESULT WE EXPANDED THE WIND ADVISORY FOR ALL SNE EXCEPT THE IMMEDIATE S COAST WHERE MIXING WILL BE MORE SHALLOW. THERE ARE A FEW SHOWERS LIFTING N ACROSS SNE BUT MOST OF THE AREA IS DRY. THROUGH MID AFTERNOON...WE ARE JUST EXPECTING A FEW SHOWERS FROM TIME TO TIME WITH MOSTLY DRY WEATHER AS MAIN ACTION WILL BE TIED TO THE COLD FRONT LATE AFTERNOON AND EVENING. LINE OF CONVECTION ALREADY DEVELOPING ALONG THE COLD FRONT ACROSS CENTRAL NY AND PA AND HIRES MODELS SHOW A STRONG SIGNAL FOR A FINE LINE OF CONVECTION ALONG THE FRONT MOVING INTO THE BERKSHIRES AND CT VALLEY LATER TODAY. RIGHT ENTRANCE REGION OF UPPER LEVEL JET WILL ENHANCE FORCING FOR ASCENT AND COMBINED WITH LOW LEVEL JET EXPECT THE FRONTAL BAND OF CONVECTION TO INTENSIFY AS IT MOVES EAST. WE HAVE A STRONGLY SHEARED ENVIRONMENT LATER TODAY WITH 0-6KM SHEAR 50-60 KT. INSTABILITY WILL BE THE LIMITING FACTOR BUT WITH TEMPS RISING THROUGH THE 70S IT LOOKS LIKE SBCAPES WILL WILL REACH 500 J/KG WITH LOW PROB OF CAPES APPROACHING 1000 J/KG. GIVEN HIGHLY SHEARED ENVIRONMENT THIS INSTABILITY ENOUGH TO SUPPORT A FEW STRONG TO SEVERE TSTMS WITH DAMAGING WINDS WITH THIS FINE LINE LATER TODAY. IN ADDITION...0-1 KM SHEAR 40-45 KT AND 0-1KM HELICITY 300-400 M2/S2 WHICH IS VERY IMPRESSIVE SO CANT RULE OUT AN ISOLD TORNADO IN THIS ENVIRONMENT. THE TIMING OF THE FRONT IS 21-00Z ACROSS W ZONES. BRIEF HEAVY RAINFALL WILL BE A SECONDARY THREAT...BUT PROGRESSIVE NATURE OF THIS FRONT WILL LIMIT DURATION OF THE HEAVIEST RAINFALL TO AN HOUR OR 2 WHICH WILL LIMIT FLOOD POTENTIAL. STILL...THE HEAVY DOWNPOURS COULD LEAD TO AREAS OF URBAN AND POOR DRAINAGE FLOODING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... TONIGHT... THE LLJ AND COLD FRONT ARE EXPECTED TO LIFT AND LOSE A LITTLE OF ITS PUNCH AS IT MOVES E...HOWEVER THE THREATS MENTIONED ABOVE REMAIN UNTIL IT MOVES OFFSHORE BETWEEN AROUND 04Z. AFTERWARD...ASIDE FROM NW WINDS GUSTING SOMEWHAT /ALTHOUGH NOT NEARLY AS STRONG AS THE SOUTHERLY WINDS AHEAD AND ASSOCIATED WITH THE FRONT/ CONDITIONS WILL RAPIDLY IMPROVE...WITH SOME CLEARING EXPECTED ALMOST TO THE E COAST BY DAYBREAK. TEMPERATURES WILL RAPIDLY DECLINE S WELL. DIPPING INTO THE 40S IN NW MA AND SRN NH. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * DRY AND SEASONABLE WEATHER TUE/WED * CHANCE OF RAIN LATE WEEK INTO NEXT WEEKEND SYNOPTIC OVERVIEW... NORTHERN STREAM TROUGH OVER THE ST. LWRNC RVR VLY EXITS NORTHEAST INTO THE MARITIMES TUE. MEANWHILE ITS ATTENDING COLD FRONT MOVES OFFSHORE WITH POST FRONTAL AIRMASS OVERSPREADING SOUTHERN NEW ENGLAND. BY WED DEEP LAYER RIDGE BUILDS OVER THE NORTHEAST AND IS ACCOMPANIED BY 1030MB SURFACE HIGH. THEN FORECAST UNCERTAINTY /ESPECIALLY TIMING/ INCREASE BY LATE IN THE WEEK AS LEFTOVER JET ENERGY FROM TODAY/S EASTERN TROUGH FORMS A WEAK MID LEVEL LOW OVER THE SOUTHEAST STATES. THIS STRENGTHENS ATTENDING SURFACE CIRCULATION AS IT TRAVERSES NORTHWARD TO THE MID ATLC COAST BY LATE IN THE WEEK. UPPER FLOW THEN BECOMES STAGNANT AS REX TYPE BLOCK DEVELOPS WITH RIDGE /POSSIBLY CLOSED ANTICYCLONE/ OVER NEW ENGLAND AND SOUTHEAST CANADA...ACCOMPANIED BY A CLOSED LOW OVER MID ATLC REGION OR JUST OFFSHORE. MODEL PREFERENCES... GOOD MODEL AGREEMENT TUE AND WED WITH RIDGING DEVELOPING OVER THE NORTHEAST. THEN MODEL SPREAD EVOLVES THU/FRI AND INTO NEXT WEEKEND. THE 00Z GFS AND ITS ENSEMBLES /GEFS/ ARE ON THE FAST AND PROGRESSIVE SIDE OF THE GUID ENVELOPE...BRINGING A COASTAL LOW WITH REMNANTS OF KAREN NORTHWARD AND POSSIBLY IMPACTING SOUTHERN NEW ENGLAND WITH A PERIOD OF RAIN AND WIND THU/FRI. THE 00Z EC IS MUCH SLOWER AND LESS PROGRESSIVE WITH RAIN AND WIND HOLDING OFF UNTIL FRI OR SAT... HOWEVER THEN POSSIBLY LINGERING PRECIP INTO SUN. THE GFS IS STRONGER/MORE AMPLIFIED WITH THE NORTHERN STREAM AND AS A RESULT THE COASTAL LOW IS KICKED SEAWARD SAT...SUPPORTING A DRYING TREND FOR NEXT WEEKEND. THE GFS MAY BE CLOSER TO CONSENSUS GIVEN ITS ENSEMBLE MEAN AND THE 00Z UKMET SUPPORT THIS PROGRESSIVE SOLUTION. ALTHOUGH GIVEN THE TIME RANGE HERE AND MODEL SPREAD THINK LOW CHANCE AND SLIGHT CHANCE POPS BETTER REFLECT THIS UNCERTAINTY...WITH HIGHEST POPS ALONG THE SOUTH COAST. IN ADDITION...DID NOT FOLLOW LIKELY POPS FROM GMOS THU INTO FRI FOR THE SAME REASON. INSTEAD STAYED CLOSE TO THE MORE CONSERVATIVE HPC GUID POPS THURSDAY THROUGH SUNDAY. SENSIBLE WEATHER... TUE AND WED...DRY AND SEASONABLY COOL. MILDER TUE AS CORE OF COOLER AIR SETTLES OVER THE REGION WED. LIGHTER WINDS WED AS 1032 MB HIGH CREST ACROSS THE AREA. THE EXCEPTION WILL BE OVER CAPE COD AND THE ISLANDS WHERE PGRADIENT WILL GET SQUEEZED A BIT YIELDING AT LEAST A MODEST NE WIND THERE. THURSDAY THROUGH SUNDAY...AS MENTIONED ABOVE LOTS OF UNCERTAINTY HERE WITH POTENTIAL COASTAL STORM. MODEL CONSENSUS WOULD SUGGEST A PERIOD OF WIND AND RAIN LATE THU INTO FRI...THEN POSSIBLY IMPROVING/DRYING TREND OVER THE WEEKEND. ALTHOUGH WE WILL GO WITH LOW CHANCE/SLIGHT CHANCE POPS TO REFLECT SOME UNCERTAINTY ON RAIN CHANCES. TEMPS NEAR NORMAL BUT PERHAPS BELOW NORMAL IF RAIN MOVES ONSHORE ESPECIALLY WITH ANY DURATION. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE IN TRENDS LOWER CONFIDENCE IN TIMING. CONDITIONS HAVE TEMPORARILY IMPROVED TO MVFR/VFR AS WARM FRONT HAS LIFTED TO THE NORTH. INCREASING S WINDS WILL DEVELOP WITH GUSTS TO 35 KT POSSIBLE THROUGH THE REST OF THE AFTERNOON...EXPECIALLY AWAY FROM S COAST. EXPECT IFR TO REDEVELOP LATER THIS AFTERNOON AND EVENING AS LINE OF SHOWERS/TSTMS MOVE THROUGH. BRIEF HEAVY RAIN AND STRONG WINDS WILL LIKELY ACCOMPANY THIS LINE OF CONVECTION...ESPECIALLY CT VALLEY THEN GRADUALLY WEAKEN AS IT MOVES TO THE COASTAL PLAIN. IMPROVING CONDIITONS TO VFR FROM WEST TO EAST 03-08Z. VFR TUESDAY. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR EXPECTED WITH A BRIEF PERIOD OF IFR POSSIBLE THIS EVENING. BRIEF HEAVY RAIN POSSIBLE 23-03Z. WIND GUSTS TO 35 KT THROUGH 00Z. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR WITH A BRIEF PERIOD OF IFR POSSIBLE LATE AFTERNOON AND EARLY EVENING. BRIEF HEAVY RAIN 21-00Z. WIND GUSTS TO 35 KT POSSIBLE THIS AFTERNOON. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUE NIGHT/WED...VFR-DRY WEATHER WITH LIGHT WINDS...EXCEPT MODEST NE WINDS CAPE COD AND THE ISLANDS. FORECAST CONFIDENCE HIGH. THU/FRI...MVFR-IFR POSSIBLE IN PERIODS OF RAIN AS A COASTAL LOW MOVES UP THE EASTERN SEABOARD. GUSTY NE WINDS POSSIBLE. FORECAST CONFIDENCE LOW. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. SOUTHERLY WINDS WILL CONTINUE TO INCREASE THROUGH THE DAY...LEADING TO SMALL CRAFT ADVISORY CONDITIONS OVER ALL THE WATERS SAVE FOR THE NRN WATERS AND WATERS IMMEDIATELY ADJACENT TO THE NORTHERN SHORELINES...WHERE SOME GUSTS TO GALE FORCE ARE POSSIBLE. GIVEN THIS...HAVE ISSUED A GALE WARNING FOR THE NORTHERN WATERS /SAVE FOR BOSTON HARBOR/ WITH SMALL CRAFT ADVISORIES ELSEWHERE. WINDS WILL RAPIDLY SHIFT TO THE NW TONIGHT BEHIND A COLD FRONT /WHICH MAY DELIVER SHORT LIVED GALE FORCE GUSTS ON ALL WATERS/ BUT THE SMALL CRAFT ADVISORY CONDITIONS REMAIN INTO TUE MORNING. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE/WED...HIGH PRES MOVES ACROSS NORTHERN NEW ENGLAND. LIGHT WINDS EXCEPT GUSTY NE WINDS SOUTHERN NEW ENGLAND WATERS. HIGH FORECAST CONFIDENCE. THU/FRI...A COASTAL STORM WILL LIKELY MOVE UP THE EASTERN SEABOARD. UNCERTAIN HOW FAR NORTH AND DURATION. HIGHEST RISK OF STRONG WINDS/LARGE SEAS AND HEAVY RAIN WILL BE SOUTH OF NEW ENGLAND. LOW FORECAST CONFIDENCE. && .HYDROLOGY... THE THREAT FOR CONVECTION AND HIGH PWAT AIRMASS WILL COMBINE TO YIELD A RISK FOR URBAN AND POOR DRAINAGE...AND POSSIBLY EVEN SMALL STREAM FLOODING AT TYPICALLY FLASHY STREAMS LATE TODAY INTO THE EARLY OVERNIGHT HOURS. THE STRONGEST LLJ AND HIGHEST MOISTURE CONTENT WILL BE IN THE WEST...ESPECIALLY WEST OF A WILLIMANTIC- WORCESTER-MANCHESTER LINE. THERE IS THE POTENTIAL FOR WIDESPREAD 1.0+ INCHES THERE...BUT LOCALLY HIGHER AMOUNTS APPROACHING 2.0 INCHES ARE POSSIBLE WITH ANY STORMS/HEAVY SHOWERS. EAST OF THE LINE...WIDESPREAD RAINFALL OF 0.5-1.0 INCHES ARE POSSIBLE AS THE LLJ WEAKENS AND DRIER AIR BUILDS IN...BUT AGAIN LOCALIZED HEAVIER AMOUNTS ARE POSSIBLE. A PROLONGED DRY SPELL WILL HELP MITIGATE THE THREAT...BUT GIVEN THAT ANY SHOWER OR STORM COULD BE HEAVY...WILL NEED TO MONITOR RAINFALL RATES/TRENDS. FINALLY...ONE OTHER NOTE IS THAT WITH LEAVES BEGINNING TO FALL...SOME CLOGGED DRAINS MAY EXACERBATE NUISANCE FLOODING IN SOME LOCATIONS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ003>007- 010>019-026. WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ002-008-009. NH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NHZ011-012-015. RI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR RIZ001>004. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ230>237-255- 256. GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ250-251-254. && $$ SYNOPSIS...NOCERA/DOODY NEAR TERM...KJC SHORT TERM...DOODY LONG TERM...NOCERA AVIATION...KJC/NOCERA MARINE...NOCERA/DOODY HYDROLOGY...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
347 PM EDT MON OCT 7 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 346 PM EDT MON OCT 7 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER THE GREAT LKS SANDWICHED BTWN UPR RDG OVER THE ROCKIES/WRN PLAINS AND ANOTHER RDG OFF THE E COAST. H925-85 THERMAL TROF ASSOCIATED WITH REINFORCING SHRTWV DIGGING INTO THE UPR LKS AND MOIST LLVLS SHOWN ON THE 12Z YPL RAOB HAVE BROUGHT QUITE A BIT OF CLD COVER TO MUCH OF THE CWA...AND THERE HAVE EVEN BEEN A FEW -SHRA...MAINLY OVER THE E HALF OF UPR MI. THE CLDS HAVE BEEN MORE SCT NEAR THE WI BORDER AND ESPECIALLY THE SCENTRAL...WHERE LLVL NW FLOW BTWN SFC LO PRES MOVING INTO QUEBEC AND HI PRES IN THE PLAINS IS DOWNSLOPING. MAIN FCST CONCERNS IN THE SHORT TERM ARE MAINLY LO CLD TRENDS/TEMPS. TNGT...SINCE THE UPR PATTERN IS RATHER PROGRESSIVE...MODELS SHOW UPR RDG AXIS TO THE W SLIDING E AND OVER THE MS RIVER VALLEY BY 12Z TUE... WITH SFC HI PRES SHIFTING INTO THE OH RIVER VALLEY. ALTHOUGH LINGERING LLVL THERMAL TROF/CYC NW FLOW WL MAINTAIN SOME LO CLDS OVER THE E HALF THIS EVNG...ARRIVAL OF SFC HI PRES RDG AXIS AND BACKING LLVL FLOW TO THE W AND THEN SW WL CAUSE SKIES TO TURN MOCLR. THERE COULD BE SOME MID/HI CLDS OVER MAINLY THE NW LATER IN THE RETURN SW FLOW...BUT THE BULK OF THIS CLD SHOULD STAY IN CANADA. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR/WINDS LIGHTER THRU THE NGT. TUE...THE CWA WL BE DOMINATED BY A STRONG SW FLOW UNDER SHARPENING PRES GRADIENT BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND SFC LO PRES IN SCENTRAL CANADA RIDING OVER THE UPR RDG. ALTHOUGH SOME DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE/WAD WL BRUSH THE NW CWA...FCST SDNGS SHOW SO MUCH LO-MID DRY AIR THAT THE ONLY IMPACT WL BE SOME HI CLDS. 12Z NAM/GFS SHOW SW H925 WINDS INCRSG TO 45-50 KTS IN THE AFTN OVER THE WRN CWA TO THE S OF PRES FALL CENTER OVER NW ONTARIO E OF THE SFC LO CENTER. MIXING TO H925 ON FCST SDNGS YIELDS HI TEMPS APRCHG 70 OVER THE W AND HINTS SOME WIND GUSTS MAY AT LEAST APRCH ADVY CRITERIA AT EXPOSED LOCATIONS OVER THE W. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 346 PM EDT MON OCT 7 2013 WITH THE UPPER TROUGH PEELING OUT OF THE UPPER GREAT LAKES REGION TONIGHT...AN UPPER RIDGE WILL BUILD OVER THE EASTERN CONUS AND REMAIN THROUGH THE END OF THE WORK WEEK. WITH A SURFACE HIGH OVER THE NEW ENGLAND STATES AND A LOW MOVING THROUGH CENTRAL CANADA...SOUTH-SOUTHWESTERLY FLOW WILL PULL WARM AIR OVER THE AREA. THIS WILL LEAD TO ABOVE NORMAL TEMPERATURES (GENERALLY IN THE MID 60S TO LOWER 70S) THROUGH THE END OF THE WORK WEEK. AS FOR WEATHER...EXPECT DRY CONDITIONS DURING THIS PERIOD WITH GENERALLY MOSTLY CLEAR SKIES. IT WILL STILL BE A LITTLE BREEZY ON WEDNESDAY AS THE PRESSURE GRADIENT IS GRADUALLY WEAKENING DUE TO THE LOW IN CANADA WEAKENING WHILE SHIFTING INTO THE CANADIAN MARITIMES. THERE ARE SOME HINTS OF FOG IN THE NAM/SREF OVER THE SOUTH CENTRAL AND EAST FOR WEDNESDAY NIGHT INTO THURSDAY MORNING. THE WEAKENING OF THE PRESSURE GRADIENT OVER THE AREA THAT STARTS ON WEDNESDAY WILL CONTINUE INTO WEDNESDAY NIGHT AND THURSDAY. SINCE SKIES WILL BE CLEAR AND IT SEEMS LIKE A BETTER RADIATIONAL COOLING NIGHT THAT MAY NOT BE TOO UNREASONABLE BUT DIDN/T ADD ANY FOG AT THIS TIME. AN UPPER TROUGH THAT DIVES INTO THE SOUTHWESTERN CONUS AROUND MID WEEK WILL BE THE MAIN WEATHER MAKER FOR THIS WEEKEND. THIS TROUGH WILL EJECT NORTHEAST INTO THE PLAINS ON FRIDAY AND THEN INTO THE UPPER MISSISSIPPI VALLEY FRIDAY NIGHT INTO SATURDAY. THE SURFACE LOW WILL FOLLOW A SIMILAR TRACK BUT THE CWA SHOULD STILL SEE AN ASSOCIATED COLD FRONT AND SHOWERS SLIDE ACROSS THE AREA ON SATURDAY. WILL CONTINUE TO SHOW THAT LINE OF SHOWERS SLIDING ACROSS THE CWA LATE FRIDAY NIGHT AND SATURDAY WITH CHANCE POPS. DID PUT IN A MENTION OF A RUMBLE OF THUNDER INTO THE GRIDS OVER THE SOUTH CENTRAL...AS THERE IS A POCKET OF MARGINAL MUCAPE VALUES ALONG THE FRONT (ALONG WITH SHOWALTER APPROACHING ZERO). BEHIND THE UPPER TROUGH...MODEL DIFFERENCES REALLY BEGIN TO GROW ON THE SMALLER SCALE FEATURES AFFECTING THE AREA. BUT THE LARGER SCALE IDEA OF AN UPPER TROUGH OVER THE WESTERN 2/3RDS OF THE CONUS AND THE UPPER GREAT LAKES REGION BEING ON THE EASTERN EDGE OF THE TROUGH. 00Z/12Z ECMWF/GEM RUNS ARE SHOWING A SECONDARY SHORTWAVE EJECTING FROM THE UPPER TROUGH AND THROUGH THE UPPER GREAT LAKES REGION ON SUNDAY INTO SUNDAY EVENING. 12Z GFS (LIKE IT/S PREVIOUS RUN) STILL HOLDS ONTO THE DRIER IDEA AND NO SHORTWAVE MOVING THROUGH. SINCE IT IS STILL A WAYS OFF...WILL FOLLOW A HIGH END SLIGHT AND LOW END CHANCE CONSENSUS FOR THE POPS AND SEE WHICH WAY THE MODELS GO. IF THE GEM/ECMWF SOLUTION PANS OUT...COULD SEE A DECENT RAINFALL FOR PORTIONS OF THE CWA ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 122 PM EDT MON OCT 7 2013 LINGERING MVFR CIGS AT THE TAF SITES WL GIVE WAY TO VFR CONDITIONS THIS AFTN WITH DAYTIME HEATING/MIXING AND THE APRCH OF HI PRES. THE GUSTY NW WINDS WL DIMINISH BY THIS EVNG FOLLOWING THE LOSS OF DAYTIME HEATING AND THE ARRIVAL OF A WEAKER PRES GRADIENT ASSOCIATED WITH THE INCOMING HI PRES. ONCE THIS RDG SHIFTS TO THE E ON TUE... EXPECT GUSTY S WINDS TO DVLP UNDER SHARPENING PRES GRADIENT IN THE PRESENCE OF DAYTIME HEATING/MIXING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 346 PM EDT MON OCT 7 2013 EXPECT NW WINDS UP TO 20 TO 30 KTS LATE THIS AFTERNOON TO DIMINISH STEADILY W-E TONIGHT AS A HI PRES RIDGE MOVES ACROSS LAKE SUPERIOR. A STRONGER S FLOW...WITH WINDS UP TO 30 KTS...WILL THEN DOMINATE LATER TUE/TUE NIGHT AS THE HI PRES SHIFTS TO THE E AND A SHARPER GRADIENT BETWEEN THIS FEATURE AND A LO PRES SYSTEM MOVING THRU SCENTRAL CANADA GETS SITUATED OVER THE UPPER LAKES. PLAN ON LIGHTER S-SW WINDS WED THRU SAT AS THE HI TO THE E REBUILDS BACK TOWARD THE AREA...RESULTING IN A WEAKER GRADIENT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1253 PM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND MOVE ACROSS THE AREA TONIGHT. THE FRONT WILL STALL OFFSHORE WITH WEAK LOW PRESSURE MOVING ALONG IT THROUGH THE END OF THE WEEK WHILE HIGH PRESSURE EXTENDS OVER THE AREA FROM THE NORTH. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1250 PM MONDAY...SHOWERS WITH A FEW EMBEDDED TSTMS STARTING TO IMPACT AREAS OF OUR FAR WESTERN CWA. LATEST 3KM HRRR IS RIGHT ON THE MONEY WITH THE PLACEMENT OF THE PRECIPITATION AND SHOWS THAT IT WILL GRADUALLY OVERSPREAD THE REGION OVER THE NEXT 3 OR 4 HOURS. INSTABILITY AND SHEAR REMAIN FOCUSED NORTH AND WEST OF OUR CWA...BUT CANNOT RULE OUT SOME WIND GUSTS APPROACHING SEVERE CRITERIA IN SOME OF THE STRONGER STORMS OVER THE NEXT 3 TO 6 HOURS. TEMPERATURES HAVE LIKELY REACHED THEIR AFTERNOON HIGHS IN THE LOW TO MID 80S AND WILL LEVEL OFF AS CLOUDS AND PRECIPITATION INCREASES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... AS OF 330 AM MONDAY...NRN PORTION OF MID LVL TROF WILL LIFT N OF AREA TONIGHT...BUT SRN PORTION WILL STILL BE WORKING OVER SE US. WIDESPREAD SHOWERS AND ISOLD TSTMS EXPECTED TO AFFECT MAINLY WRN SECTIONS THIS EVENING. FRONT WILL GRADUALLY PUSH ACROSS AREA OVERNIGHT...AND DEVELOPING N TO NE LOW LVL WINDS COMBINED WITH LINGERING MID LVL ENERGY FROM S-SW WILL LEAD TO HIGHEST POPS OVER SRN PORTIONS AFTER MIDNIGHT. MOS BLEND FOR TEMPS...MAINLY LOW-MID 60S. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 330 AM MON...BY TUES MORNING THE SURFACE FRONT WILL BE OFFSHORE WITH HIGH PRESSURE BUILDING EAST OVER THE MID-ATLANTIC STATES. THE UPPER RIDGE OVER THE SOUTHERN CONUS WILL SHIFT EAST TOWARDS THE CAROLINAS AS THE REMNANTS OF TS KAREN SLOWLY MOVE OVER NORTHERN FL AND EVENTUALLY OFF THE GA/SC COAST. THE FRONT WILL STALL OFFSHORE WITH A SURFACE LOW DEVELOPING OFF THE COAST. THE LOW WILL SLOWLY MIGRATE NE ALONG/OFF THE COAST TUES NIGHT INTO THURS PRODUCING AN UNSETTLED PATTERN ACROSS THE REGION. INCREASED POPS TO NEAR CATEGORICAL TUES GIVEN GOOD MODEL AGREEMENT WITH GOOD MOISTURE AND STRONG SHORTWAVE ALOFT. KEPT CHANCE POPS ACROSS THE REGION WED THEN SLIGHT CHANCE INLAND/CHANCE EAST OF HWY 17 WED NIGHT INTO THURS AS THE LOW MIGRATES NE. THE SLOW EVOLUTION OF THIS PATTERN WILL LEAD TO A PROLONGED PERIOD OF GUSTY NE WINDS TO THE COASTAL OBX AREAS. UPPER LOW WILL DRIFT NORTH BY LATE WEEK TAKING BEST SHOWER CHANCES WITH IT. BEST POPS WILL RESIDE IN THE NORTHEAST DURING THIS PERIOD. THE UPPER LOW WILL SHIFT BACK OVER THE REGION SAT/SUN YIELDING MORE CLOUDS/CHANCES FOR PRECIP. FOR TEMPS...EXPECT BE BELOW CLIMO...ESPECIALLY FOR MAX TEMPS AS CLOUDS AND PRECIP KEEP TEMPS DOWN INTO THE UPPER 60S TO NEAR 70 INLAND. LOWS WILL GENERALLY BE IN THE 50S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... SHORT TERM /THROUGH 12Z TUESDAY/... AS OF 1250 PM MONDAY...SHOWERS AND SCATTERED TSTMS WILL BECOME WIDESPREAD THROUGH MID TO LATE AFTN AHEAD OF APPROACHING COLD FRONT AND CONTINUE THROUGH EVENING WITH CONDITIONS LOWERING TO MVFR. SRLY WINDS WILL GUST TO AROUND 20 KT AHEAD OF THE FRONT. MVFR CIGS WILL CONTINUE WITH PATCHY RAIN LATE TONIGHT AS WINDS SHIFT TO N-NE BEHIND FRONT. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 320 AM MON...COLD FRONT WILL PUSH OFF THE NC COAST EARLY TUES MORNING WITH SHOWERS CONTINUING TUES INTO WED. UNFAVORABLE AVIATION CONDITIONS EXPECTED TO PERSIST TUES THROUGH WED WITH IFR CONDITIONS POSSIBLE AS MOIST NORTHEAST FLOW DEVELOPS WITH UPPER LOW LINGERING OVER THE VICINITY. WINDS WILL BE GUSTY AT TIMES AS WELL WITH HIGH PRESSURE INLAND AND LOW PRESSURE OVER THE WATERS PRODUCING A NE GRADIENT. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 1250 PM MONDAY...WINDS GRADUALLY STARTING TO RAMP UP OVER THE COASTAL WATERS AND SOUNDS AS THE FRONT EDGES CLOSER. MOST AREAS WILL BE IN THE 15 TO 20 KNOT RANGE WITH SEAS IN THE 3 TO 5 FOOT RANGE. WINDS/SEAS INCREASE A BIT MORE OVERNIGHT WITH FREQUENT GUSTS TO 25 KNOTS AND SEAS BUILDING TO AS HIGH AS 6 TO 7 FEET BY LATER THIS EVENING. WINDS/SEAS WILL ALSO BE ELEVATED IN CONVECTION. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 315 AM MON...COLD FRONT WILL RESIDE JUST ALONG THE COAST BY EARLY TUES MORNING THEN SHIFT OFFSHORE THROUGHOUT THE DAY...WITH A STRONG NE SURGE OF WINDS EXPECTED TO BUILD SOUTH OVER THE WATERS. NE GRADIENT WILL PERSIST WED/THURS DUE TO HIGH PRESSURE OVER THE NORTHEASTERN CONUS AND WEAK SURFACE LOW/REMNANTS OF TS KAREN OFF THE SOUTHEASTERN COAST. NE WINDS WILL RANGE 20-25 KT TUES THROUGH WED AFTERNOON. SEAS WILL RESPOND BY BUILDING 5-8 FT TUES/TUES NIGHT ACROSS THE NORTHERN AND CENTRAL WATERS...WITH 4-7 FT EXPECTED ACROSS THE SOUTHERN WATERS. WEAK SURFACE LOW SHIFTS NORTH TO OFF THE NORTH CAROLINA COAST THURS INTO FRI...ACTING TO VEER WINDS MORE N/NW AND DIMINISH SPEEDS TO 10-20 KT...HOWEVER...SEAS WILL REMAIN ELEVATED THROUGH MID WEEK ESPECIALLY FROM DIAMOND SHOALS NORTH. USED A BLEND OF PREVIOUS FORECAST WITH LATEST NON-GFS MODEL BLEND FOR WINDS. FOR SEAS...UTILIZED LOCAL SWAN/NWPS THROUGH WED THEN VERY SMALL ADJUSTMENTS TO PREVIOUS SEAS FORECAST FOR THURS/FRI WHICH HAD ALREADY TAKEN INTO ACCOUNT THE KNOWN BIAS OF UNDER-FORECAST SEAS FOR NE/N FLOW ACROSS THE CENTRAL AND NORTHERN WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 PM EDT THURSDAY FOR AMZ130-135. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 4 AM EDT FRIDAY FOR AMZ152-154. SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 4 PM EDT THURSDAY FOR AMZ156-158. SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 AM EDT FRIDAY FOR AMZ150. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...DAG AVIATION...JBM/CTC/DAG MARINE...JBM/DAG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
156 PM EDT MON OCT 7 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE NORTHEASTERN STATES WILL GIVE OUR AREA A COOL NORTHEAST FLOW OF AIR THROUGH MUCH OF THE WEEK. EXPECT LOW PRESSURE TO MOVE FROM THE GEORGIA COAST TO EASTERN NORTH CAROLINA DURING MID WEEK AND STAY IN THAT VICINITY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... AS OF 10AM EDT MONDAY...BROKEN LINE OF CONVECTION CONTINUES TO PUSH EAST OF THE I77 CORRIDOR INTO CENTRAL NC. A FEW LIGHT SHOWERS WILL BE A POSSIBILITY OVER THE NEXT FEW HOURS BEHIND THE LEADING LINE. THEREFORE KEPT CHANCE POPS THROUGH MIDDAY OUTSIDE OF THE MOUNTAINS. OTHERWISE...DECIDED TO GO AHEAD AND LOWER POPS ACROSS THE HIGHER TERRAIN AS THE FRONT PUSHES THROUGH ADVECTING IN MUCH MORE STABLE AIR. SKY CONDITIONS WILL SLOWLY IMPROVE ACROSS THE MOUNTAINS THROUGH THE DAY AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT. ELSEWHERE...CLOUDS WILL PERSIST THROUGH THE AFTERNOON HOURS AND INTO MONDAY EVENING AS DEEP LAYER MOISTURE PREVAILS AHEAD OF THE FRONT. OTHER THAN THE ABOVE MENTIONED POP/WX/SKY ADJUSTMENTS...NO OTHER CHANGES WERE MADE TO THE FCST AT THIS TIME. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 130 PM MON...LOW PRES OVER THE SE COASTAL WATERS TUE NIGHT WILL PUSH ATLANTIC AND TROPICAL MOISTURE BACK INLAND ACROSS THE COASTAL PLAIN OF THE CAROLINAS THROUGH WED. THE MAJORITY OF THE 12Z MODEL RUNS KEEP THE HEAVY PRECIPITATION WITH THIS SYSTEM CONFINED TO MAINLY COASTAL SECTIONS. HOWEVER...THE CANADIAN CMC AND A FAIR CHUNK OF THE ENSEMBLE MEMBERS THROW A BIT MORE PRECIPITATION WESTWARD INTO THE PIEDMONT TUE NIGHT/WED. WILL LEAN TOWARD THE MORE AGGRESSIVE SOLUTION GIVEN THE HEALTHY PRESENTATION ON WATER VAPOR TODAY OF THE WAVE THAT BECOMES THE COASTAL SYSTEM. DESPITE LEANING TOWARD THE WETTER SIDE OF GUIDANCE...THE BL TO 850 MB FLOW WILL REMAIN NRLY ENOUGH AROUND THE COASTAL SYSTEM TO KEEP QPF AMOUNTS DOWN AND NOT ALLOW MUCH OF ANY UPSLOPE ENHANCEMENT INTO THE BLUE RIDGE THROUGH WED NIGHT. THE MAIN FEATURE TO WATCH WOULD BE IF ANY BANDED SHOWERS COULD WRAP BACK INTO THE CLT AREA. OTHERWISE...WILL CONTINUE TO FEATURE A SMALLER THAN GUIDANCE DIURNAL RANGE ON TEMPS. AS THE SYSTEM MOVES UP THE COAST TO THE OUTER BANKS ON THU...MOISTURE MAY CONTINUE TO WRAP BACK WWD INTO THE NC PIEDMONT. ANY ADDITIONAL QPF AMOUNTS WOULD BE LIGHT. WILL CONTINUE TO FEATURE TEMPS BELOW GUIDANCE ON THU AFTN...BUT LESS SO THAN ON WED. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AS OF 140 PM MON FOR THE MEDIUM RANGE...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST HANGS AROUND OVER EASTERN NC AND VA INTO SATURDAY THEN EITHER MOVES EAST OR NORTH DEPENDING ON MODEL CHOICE. THIS LOW IS CLOSE ENOUGH TO PRODUCE SOME LIGHT PRECIP JUST EAST OF OUR ZONES THURSDAY EVENING AND THEN HIGH PRESSURE TO OUR WEST AND NORTH BECOMES MORE OF AN INFLUENCE. THE GFS AND ECMWF KEEP THE LOW OVER EASTERN NC THROUGH SATURDAY. THE ECMWF THEN MOVES THE LOW NORTH UP THE COAST TO MASS EARLY IN THE WEEK. THE GFS MOVES THE LOW EAST AND THEN NORTH TOWARD NOVA SCOTIA. THE GFS KEEPS AN ALMOST PERSISTENT LOW LEVEL NE WIND FLOW OVER OUR AREA THROUGH MOST OF THE PERIOD. THE ECMWF HAS A MORE LIGHT AND VARIABLE WIND FLOW. SOME SHORTWAVE ENERGY WILL BE CROSSING THE LOWER MISSISSIPPI VALLEY BY MONDAY NIGHT AND INCREASE CLOUDS OVER NE GA AND THE MTNS. STILL KEEPING IT DRY THROUGH THE PERIOD. TEMPERATURES WILL BE NEAR NORMAL FOR THIS MEDIUM RANGE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH THE ONLY POSSIBLE EXCEPTION BEING FOR SCATTERED AFTERNOON TSRA. ADDED AN MVFR TEMPO GROUP FROM 19Z-23Z TO ACCOUNT FOR LOW END INSTABILITY ACROSS THE NC PIEDMONT THIS AFTERNOON. MODEL SOUNDINGS INDICATE MARGINAL INSTABILITY THUS COULD NOT RULE OUT CONVECTION. OTHERWISE...SKIES SHOULD REMAIN BKN/OVC THROUGH THE REMAINDER OF THE TAF CYCLE AS MOISTURE AXIS ASSOCIATED WITH FRONTAL BOUNDARY STALLS ALONG AND SOUTH OF THE I85 CORRIDOR. INITIALIZED WINDS OUT OF THE WEST THEN VEERING NORTHWEST BY AROUND 19Z AS THE FRONT PUSHES THROUGH. WINDS WILL REMAIN ELEVATED THROUGH THE EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTH. AS THIS RIDGE BUILDS OVERNIGHT...INCREASING PRESSURE GRADIENT FORCES WILL YIELD THE POSSIBILITY FOR GUSTY WINDS IN THE MORNING. THUS ADDED MENTION OF NORTHEAST GUSTS NEARING 20KTS THROUGH MIDDAY. ELSEWHERE...VFR CONDITIONS SHOULD PREVAIL THROUGH THE ENTIRE TAF CYCLE. WITH THAT SAID...DID INITIALIZE KAND WITH A BKN MVFR CIG WHICH SHOULD NOT LAST BUT FOR MORE THAN AN HOUR OR SO. OTHERWISE...SKIES SHOULD SLOWLY CLEAR IN THE LOW/MID LEVELS FROM WEST TO EAST AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT AT KAVL. AS FOR OTHER LOCATIONS...KEPT MENTION OF LOW END VFR CIGS THROUGH THE REMAINDER OF THE TAF CYCLE DUE TO PROXIMITY OF STALLED MOISTURE AXIS. AS WITH KCLT ABOVE...WINDS WILL SHIFT NORTHWESTERLY THROUGH THE FIRST FEW HORUS OF THIS TAF PERIOD AND WILL REMAIN ELEVATED OVERNIGHT. THESE ELEVATED WINDS COMBINED WITH SFC DEWPOINTS IN THE 40S TO LOWER 50S WILL KEEP FOG CHANCES SLIM. WINDS WILL INCREASE FURTHER AND VEER EASTERLY DURING THE MORNING HOURS WITH SOME GUSTING AT KGSP AND KGMU. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW AND MOISTURE ASSOCIATED WITH THE REMNANTS OF TROPICAL STORM KAREN MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES LATER IN THE WEEK. CONFIDENCE TABLE... 18-24Z 00-06Z 06-12Z 12-18Z KCLT HIGH 93% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 98% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 97% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 87% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...CDG/WIMBERLEY SHORT TERM...HG LONG TERM...DEO AVIATION...CDG
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
239 PM CDT MON OCT 7 2013 .SHORT TERM.../NOW THROUGH TUESDAY NIGHT/...AS MR. RODGERS WOULD SAY...IT IS A BEAUTIFUL DAY IN THE NEIGHBORHOOD...AND IT WILL REMAIN BEAUTIFUL THROUGH THE SHORT TERM PERIOD. MID LEVEL RIDGE MOVES INTO WESTERN TEXAS AND SURFACE RIDGE PARKS ITSELF OVER SOUTH TEXAS TONIGHT. ATMOSPHERE REMAINS VERY DRY WITH THE LIGHT OFFSHORE FLOW CONTINUING INTO TUESDAY BEFORE VEERING SOUTHEAST TUESDAY NIGHT. WARM DAYS AND COOL NIGHTS CONTINUE UNDER THE CLEAR SKIES AND LOW DEW POINT AIR. MODEL TEMPERATURES GUIDANCE REMAINS CONSISTENT BUT WILL TREND SLIGHTLY LOWER FOR OVERNIGHT LOWS AS EXCELLENT RADIATIONAL COOLING TAKES PLACE. A FEW DEGREES WARMER ON TUESDAY WITH FORECAST NUMBERS NOT STRAYING TO FAR GUIDANCE. AS WE HEAD INTO TUESDAY NIGHT SOUTHEAST WINDS RETURN ALBEIT WEAK. SOMEWHAT MODEST LOW LEVEL MOISTURE ADVECTION IN THE LOWER 3000 FEET...LIGHT WINDS AND MOSTLY CLEAR SKIES COULD RESULT IN SOME PATCHY GROUND FOG BY SUNRISE WEDNESDAY. UNSURE IF MOISTURE ADVECTION WILL BE SUFFICIENT FOR DENSE FOG FORMATION BUT VISIBILITIES COULD LOWER BELOW 1 MILE IN THE MORE FAVORED LOCATIONS IN THE KHBV KBKS AREAS. OVERNIGHT NIGHT LOWS WILL BE WARMER BUT STILL BELOW GUIDANCE VALUES WITH THE WEAK RETURN FLOW NOT ADDING MUCH WARM AIR ADVECTION AT THIS TIME. ENJOY IT NOW A/C MAY HAVE TO CRANKED UP SOON. .LONG TERM.../WEDNESDAY THROUGH MONDAY NIGHT/... UPPER LEVEL TROUGH OVER THE WESTERN U.S. WILL DEPEND AND LIFT TO THE NORTHEAST ACROSS THE FOUR CORNERS REGION THURSDAY INTO FRIDAY. AT THE SURFACE...STRONG SURFACE LEE TROUGH DEVELOPS ENHANCING THE SOUTHEAST FLOW FROM THE CENTRAL PLAINS SOUTHWARD INTO SOUTH TEXAS REGION. EXPECT THIS BREEZE AFTERNOON THROUGH THURSDAY. WARM FRONT OVER THE SOUTHERN GULF WILL LIFT N/NW AS RIDGE BUILDS ACROSS THE REGION. THIS SURFACE LOW WILL SURGE DEEP LAYER MOISTURE FROM THE SOUTHERN GULF INTO THE CWA THURSDAY AND FRIDAY. THE 1000 TO 500 MB RH VALUES SHOWS AN INCREASE BETWEEN 60 TO 70 PERCENT THROUGH THE WEEKEND AS THE UPPER LEVEL LOW INTERACTS WITH RIDGE OVER SOUTH TEXAS. THIS WILL ENHANCE THE CHANCE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE CWA FRIDAY AND INTO THE WEEKEND. DECIDED TO INCREASE POP FORECAST TO 20 PERCENT AT THIS TIME SINCE THERE IS GOOD AGREEMENT AND CONSISTENCY WITH THE GFS/ECMWF MODEL RUN. THE COASTAL COUNTIES ARE MORE FAVORABLE TO RECEIVE SOME RAINFALL FROM THIS MOISTURE SURGE. DAYTIME HIGHS WILL GRADUALLY WARM TO THE MID 90S THROUGH THE END OF THE LONG TERM FORECAST. BY NEXT WEEK...GULF MOISTURE WILL RAP AROUND THE PERIPHERY OF THE HIGH AND ENHANCE THUNDERSTORM ACTIVITY ALONG THE SIERRA MADRE AND CENTRAL TEXAS. THIS AREA OF CONVECTION WILL CONTINUE INTO TUESDAY UNTIL THE NEXT UPPER TROUGH DEEPENS PUSHING ALL THE MOISTURE OUT OF THE AREA POSSIBLY BY MID WEEK. && .MARINE...NOW THROUGH TUESDAY NIGHT...EXCELLENT MARINE CONDITIONS THROUGH TUESDAY NIGHT WITH SURFACE HIGH PRESSURE SETTLING OVER THE COASTAL WATERS. LIGHT NORTHEAST WINDS TONIGHT TO VEER EAST TUESDAY THEN SOUTHEAST TUESDAY NIGHT. SEAS CONTINUE TO FALL TONIGHT LOWERING TO 2 FEET OR LESS TUESDAY. WEDNESDAY THROUGH MONDAY NIGHT... SOUTHEAST WINDS RETURN WEDNESDAY AS THE HIGH PRESSURE BUILDS ACROSS THE AREA. THIS SOUTHEAST FLOW WILL INCREASE THURSDAY INTO FRIDAY AND BUILD SEAS BELOW ADVISORY CRITERIA THROUGH THE END OF THE WEEK. AN AREA OF LOW PRESSURE WILL MOVE NORTHWARD INTO THE MARINE ZONES THURSDAY INTO FRIDAY ENHANCING THE MOISTURE CONTENT IN THE AREA. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE SATURDAY THROUGH MONDAY OVER THE GULF WATERS AS THE ABUNDANT MOISTURE WILL BE HIGHEST OVER THE MARINE ZONES. NO SCA OR SCEC EXPECTED AT THIS TIME THROUGH MONDAY. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 60 87 68 88 / 0 0 0 0 BROWNSVILLE 59 88 66 90 / 0 0 0 0 HARLINGEN 56 89 64 90 / 0 0 0 0 MCALLEN 59 91 66 91 / 0 0 0 0 RIO GRANDE CITY 58 91 65 92 / 0 0 0 0 SOUTH PADRE ISLAND 68 84 74 87 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 59/67