FXUS61 KALY 010838 AFDALY AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 438 AM EDT SUN AUG 1 2010 .SYNOPSIS... UNSETTLED WEATHER IS EXPECTED INTO MID WEEK. WEAK DISTURBANCES IN THE UPPER LEVELS OF THE ATMOSPHERE WILL MOVE OVER THE REGION. A COLD FRONT WILL APPROACH FROM THE NORTHWEST AND CROSS THE REGION WEDNESDAY. HUMIDITY LEVELS WILL BE ON THE INCREASE. && .NEAR TERM /THROUGH TONIGHT/... FEATURES REMAIN SUBTLE AND FORCING WEAK. SHORT WAVE MOVING THROUGH THE LONGWAVE TROUGH WILL PASS TO OUR SOUTH AND THE TROUGH AXIS WILL SWING THROUGH. AT THE SURFACE...AN INVERTED TROUGH EXTENDS EASTWARD INTO CENTRAL/EASTERN PA BUT IT NOT EXPECTED TO REACH OUR AREA. THE MODELS ARE LESS PRONOUNCED WITH THE 700 AND 850 MB THETA-E RIDGES ACROSS OUR AREA. HOWEVER...WITH SURFACE HIGH SHIFTING OFFSHORE A SOUTHERLY FLOW WILL DEVELOP TODAY AND DEW POINTS/MOISTURE WILL BE IN THE RISE. RADAR INDICATES SHOWERS ASSOCIATED WITH SHORT WAVE ARE OCCURRING ACROSS PA EARLY THIS MORNING. THE BEST CHANCES FOR SHOWERS AND PERHAPS A THUNDERSTORM ARE ACROSS THE EASTERN CATSKILLS INTO THE MID HUDSON VALLEY...WHILE THE INFLUENCE OF THE RIDGE KEEPS CHANCES LOWER ACROSS THE REST OF THE LOCAL AREA. WITH LOSS OF DAYTIME HEATING CHANCES FOR SHOWERS WILL DECREASE BUT CAN NOT BE COMPLETELY RULED OUT AS ANOTHER SHORT WAVE MOVES THROUGH THE TROUGH. KEPT FORECAST SIMPLE AS TIMING OF THE INDIVIDUALS SHORT WAVES BY THE MODELS HAS NOT BEEN CONSISTENT WITH THE FAST FLOW. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... HEIGHTS RISE AS UPPER TROUGH AXIS MOVES OFF TO OUR EAST AND RIDGE STRENGTHENS OVER THE SOUTHERN PLAINS AND SOUTHEASTERN UNITED STATES. FLOW FLATTENS AND THE SHORT WAVES KEEP COMING. WITH THE HELP OF DAYTIME HEATING EXPECT CONVECTION TO DEVELOP MONDAY. A STRONGER SHORT WAVE WILL APPROACH TUESDAY AND WITH THE HELP OF DAYTIME HEATING CONVECTION IS EXPECTED AGAIN. INSTABILITY SHOULD BE LIMITED TUESDAY...HOWEVER FLOW ALOFT WILL INCREASE AS THE SHORT WAVE APPROACHES. MODELS INDICATE VERTICAL SHEAR COULD BECOME SUFFICIENT FOR SOME ORGANIZED CONVECTION. AGAIN HAVE KEPT FORECAST SIMPLE AS THERE ARE DIFFERENCES IN TIMING THE INDIVIDUALS SHORT WAVES MOVING ACROSS THE REGION. HUMIDITY LEVELS WILL GET UNCOMFORTABLE AS DEWPOINTS RISE WELL INTO THE 60S WITH SOME LOWER 70S POSSIBLE BY TUESDAY EVENING. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE EXTENDED FORECAST BEGINS WITH ZONAL FLOW ALOFT...AND A COLD FRONT SLOWLY DESCENDING S/SE FROM THE ST LAWRENCE RIVER VALLEY...AND THE ERN GREAT LAKES REGION ON WEDNESDAY. THIS FRONT WILL FOCUS SOME SHOWERS AND THUNDERSTORMS...AS A WARM AND HUMID AIR MASS WILL BE IN ADVANCE OF IT. THE GFS CONTINUES TO ADVERTISE A DEEPLY SHEARED ENVIRONMENT IN PLACE WITH 0-6 KM BULK SHEAR VALUES OF 35-50 KTS...AND SBCAPES OF 1000-2000 J/KG. AN IMPRESSIVE MID AND UPPER LEVEL JET STREAK WILL BE PASSING NORTH OF THE REGION TOO. IF ENOUGH SURFACE DESTABILIZATION/HEATING OCCURS...THEN SOME STRONG/SEVERE THUNDERSTORMS MAY DEVELOP IN THE AFTERNOON. THE MODEL SOUNDINGS CONTINUE TO SHOW UNIDIRECTIONAL FLOW IN THE LOWER AND MID TROPOSPHERE...WHICH WOULD INDICATE A LINE OR TWO OF CONVECTION. IF THE FRONT IS FASTER PASSING IN THE MORNING...WHICH THE LATEST ECMWF ADVERTISES...THEN THE LIKELIHOOD OF STRONGER STORMS WOULD DECREASE. SFC DEWPOINTS WILL RANGE FROM THE M60S TO L70S. PRECIPITABLE WATER VALUES ARE PROGGED IN THE 1.5-2+ INCH RANGE. THESE VALUES WOULD BE 1-2 STANDARD DEVIATIONS ABOVE NORMAL BASED ON THE GLOBAL ENSEMBLES INDICATIVE OF SOME HEAVY DOWNPOURS WITH ANY CONVECTION. WE WILL CONTINUE WITH CHANCES OF SHOWERS AND THUNDERSTORMS INTO WEDNESDAY EVENING. MAX TEMPS ARE EXPECTED TO BE IN THE MID 80S TO NEAR 90F ACROSS THE VALLEYS AND HILLS...WITH U70S TO L80S OVER THE MTNS. THURSDAY...THE FRONT SLIDES SOUTH OF THE REGION...AND HANGS UP OVER THE UPPER MID ATLANTIC REGION...AND THE SRN NEW ENGLAND COAST. THE CLOSE PROXIMITY OF THE FRONT IN THE MORNING WARRANTED THE CONTINUED INCLUSION OF SLIGHT CHANCE POPS FOR SHOWERS FOR THE FIRST PORTION OF THE DAY. DRIER AIR WILL BE INFILTRATING THE REGION FROM THE NORTH AND WEST DURING THE AFTERNOON. HUMIDITY LEVELS SHOULD DECREASE A BIT WITH A WEAK PUSH OF COLD AIR ADVECTION. H850 TEMPS FALL TO 15-16 C WHICH IS SLIGHTLY ABOVE NORMAL FOR EARLY AUG. THURSDAY NIGHT INTO FRIDAY...A SECONDARY COLD FRONT OR SFC TROUGH APPROACHES COUPLED WITH A SHORTWAVE IN THE W/NW FLOW ALOFT. THIS FRONT AND ASSOCIATED SHORTWAVE WILL LIKELY FOCUS SOME ISOLD SHOWERS ESPECIALLY FROM THE CAPITAL REGION NORTH DURING THE DAY ON FRIDAY. WE PLACED SOME SLIGHT CHANCE POPS IN. FRIDAY NIGHT INTO THE WEEKEND...HIGH PRESSURE BUILDS IN FROM THE ERN GREAT LAKES REGION WITH LOWER HUMIDITY LEVELS AND DRY WEATHER. H850 TEMPS WILL STILL BE AROUND 15 C WHICH WILL ALLOW TEMPS TO BE NEAR OR SLIGHTLY ABOVE SEASONAL VALUES. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... SFC HIGH PRESSURE CONTINUES TO MOVE EAST OF THE GULF OF MAINE THIS MORNING. AN INVERTED SFC TROUGH EXTENDING NORTHEAST OF LOW PRESSURE NEAR THE TN VALLEY WILL INCREASE CLOUDS WITH SCT SHOWERS IMPACTING PORTIONS OF CNTRL-ERN NY LATE THIS AFTERNOON. VFR CONDITIONS WILL PREVAIL MAINLY TODAY. KGFL HAS MOSTLY CLEAR AND CALM CONDITIONS THIS MORNING WITH SOME RADIATIONAL MIST FORMING. PERIODIC LAPSES TO IFR/MFR VSBYS WILL CONTINUE. A TEMPO HAS BEEN USED TO ADDRESS THE MIST. EXPECT SOME SCT-BKN CIRRUS CLOUDS TO MOVE IN FROM THE S/SW FOR KALB AND KPOU PRIOR TO DAY BREAK. THE CLOUDS WILL CONTINUE TO THICKEN AND LOWER THROUGHOUT THE LATE MORNING AND AFTERNOON. THE BEST CHANCE FOR SOME DIURNALLY TIMED ISOLD-SCT SHOWERS TO IMPACT E-CNTRL WILL BE FROM KALB SOUTH AFT 18Z. VCSH GROUPS WERE ADDED TO KPOU AND KALB. A CB HAS BEEN INCLUDED AT KPOU AFT 20Z WHERE SOME INSTABILITY MAY BE REALIZED WITH ISOLD TSRAS DEVELOPING. THE INFLUENCE OF THE OFFSHORE HIGH HAS SHOWN A DECREASE IN MOISTURE THE FURTHER NORTH ONE GOES ACCORDING THE NAM/GFS. WE HAVE NOT ADDED ANY VCSH GROUPS AT KGFL. THE THREAT FOR -SHRAS CONTINUES INTO THE EARLY EVENING...BEFORE THE DIURNAL HEATING IS LOST. THE WINDS WILL BE LIGHT TO CALM THIS MORNING. THEY WILL GENERALLY BE FROM THE S/SE AT LESS THAN 10 KTS DURING THE AFTERNOON...BEFORE BECOMING LIGHT TO CALM OVERNIGHT. OUTLOOK... MON/TUE/WED...VFR/MVFR CIGS...CHC OF -SHRA/-TSRA. THU...VFR. SLIGHT CHC -SHRAS. && .FIRE WEATHER... UNSETTLED WEATHER IS EXPECTED INTO MID WEEK. WEAK DISTURBANCES IN THE UPPER LEVELS OF THE ATMOSPHERE WILL MOVE OVER THE REGION. A COLD FRONT WILL APPROACH FROM THE NORTHWEST AND CROSS THE REGION WEDNESDAY. HUMIDITY LEVELS WILL BE ON THE INCREASE. RELATIVE HUMIDITY VALUES WILL DROP TO MINIMUMS OF 45 TO 55 PERCENT THIS AFTERNOON AND RECOVER TO NEAR 100 PERCENT TONIGHT. MINIMUMS MONDAY AFTERNOON WILL BE IN THE 60S WITH A RECOVERY TO NEAR 100 PERCENT MONDAY NIGHT. WINDS WILL BECOME SOUTHERLY BY THIS AFTERNOON AT LESS THAN 10 MPH AND WILL SO THROUGH MONDAY. && .HYDROLOGY... NO HYDRO PROBLEMS ARE ANTICIPATED OVER THE NEXT FEW DAYS. RIVER FLOWS REMAIN AT NORMAL TO BELOW NORMAL LEVELS ACROSS THE REGION FOR LATE JULY. MODELS HAVE NOT BEEN CONSISTENT WITH THE AMOUNT OF RAINFALL. OVERALL QPF IS EXPECTED TO BE LIGHT. HOWEVER...AS HUMIDITY LEVELS AND PRECIPITABLE WATER VALUES INCREASE HEAVY DOWNPOURS WILL BE POSSIBLE WITH SOME THUNDERSTORMS. THE BEST CHANCES FOR THIS WILL BE A COLD FRONTAL PASSAGE. 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...IAA NEAR TERM...IAA SHORT TERM...IAA LONG TERM...WASULA AVIATION...WASULA FIRE WEATHER...IAA HYDROLOGY...IAA