000 FXUS61 KALY 062347 AFDALY AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 747 PM EDT MON JUL 6 2009 .SYNOPSIS... ANOTHER UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION THROUGH WEDNESDAY...BRINGING MORE UNSETTLED WEATHER AND BELOW NORMAL TEMPERATURES. A BRIEF DRY PERIOD WITH MODERATING TEMPERATURES IS EXPECTED TOWARDS THE END OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 400 PM...SMALL SCALE UPPER LEVEL DISTURBANCE NOTED ON WATER VAPOR IMAGERY ADVANCING EASTWARD ACROSS THE EASTERN GREAT LAKE AT THIS TIME. JET DYNAMICS AND LOW LEVEL MOISTURE ARE LACKING AS THE SYSTEM APPROACHES. MONITORING CONVECTIVE DEVELOPMENT...A CLUSTER OF SHOWERS WITH SOME EMBEDDED THUNDER NOW MOVING ACROSS THE SOUTHERN ADIRONDACKS/LAKE GEORGE REGION NOW. THIS ACTIVITY IS NOT VERY STRONG THOUGH...AS LIMITED SBCAPE DUE TO FAIRLY DRY BOUNDARY LAYER INHIBITING SIGNIFICANT UPDRAFTS. DEEP LAYER SHEAR IS IMPRESSIVE...GREATER THAN 40 KT...HOWEVER STORMS ARE NOT GROWING TALL ENOUGH TO BE AFFECTED BY THIS SHEAR. ACCORDING TO SPC RUC ANALYSIS...BEST SBCAPE AROUND 1000 J/KG EXISTS ACROSS THE ADIRONDACKS. THIS EVEN MAY BE OVERDONE...AS THE DEWPOINT HAS DROPPED TO 47 AT SLK THIS PAST HOUR. ELSEWHERE GENERALLY 500 OR SO J/KG TO WORK WITH...AS SURFACE DEWPOINTS STILL MAINLY IN THE LOWER TO MID 50S ACROSS THE AREA...WITH NO SUBSTANTIAL INCREASE EXPECTED. LOW LEVEL LAPSE RATE ARE QUITE STEEP THOUGH...SO SOME THUNDERSTORMS COULD PRODUCE SOME GUSTY WINDS. ALSO...DUE TO LOW WBZERO HEIGHTS CLOSE TO 7000 FT...ISOLATED SMALL HAIL MAY OCCUR. NOT EXPECTING ENOUGH COVERAGE TO MENTION IN THE GRIDS...BUT WILL MAKE NOTE IN THE HWO. WILL KEEP MENTION OF 30-50 POPS FOR MUCH OF THE AREA...DECREASING TO 20 PERCENT ACROSS SOUTHEAST AREAS. WILL TAKE OUT MENTION OF THUNDER AFTER 02Z AS DIURNAL HEATING DIMINISHES. WHILE NOT AS COOL AS LAST NIGHT...TEMPS SHOULD DROP TO SLIGHTLY BELOW NORMAL FOR MINS TONIGHT WITH BREAKS IN THE CLOUDS EXPECTED...ESPECIALLY FROM THE MOHAWK VALLEY AND CAPITAL REGION SOUTHWARD. GENERALLY LOWER 50S ACROSS THE HIGHER ELEVATIONS...AND MID TO UPPER 50S IN THE VALLEYS. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... TUESDAY IS SHAPING UP TO BE A VERY CONVECTIVELY ACTIVE DAY ACROSS THE AREA. SPC HAS PLACED MOST OF THE FORECAST AREA IN A SLIGHT RISK OUTLINE FOR SEVERE THUNDERSTORMS...AND THIS CERTAINLY SEEMS WARRANTED DUE TO THE EXPECTED SET UP. THE CUT-OFF LOW NOW POSITIONED ACROSS THE BORDER OF SOUTHERN ONTARIO/QUEBEC...WILL GRADUALLY DRIFT SOUTHEAST TO A POSITION JUST NORTH OF LAKE ONTARIO BY LATE TOMORROW. LARGE SCALE ASCENT WILL INCREASE ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND...AS A STRONG UPPER LEVEL JET MOVES ACROSS OHIO/PA DURING THE DAY. OUR AREA WILL BE IN THE OPTIMAL LEFT FRONT QUAD OF THIS 100+ KT JET FOR DIVERGENCE ALOFT. CONVECTION WILL BE FOCUSED BY A SURFACE OCCLUDED BOUNDARY MOVING THROUGH. SBCAPE FORECAST DIFFICULT DUE TO QUESTIONABLE MOISTURE. NAM12 SHOWING POCKETS OF 2000 J/KG...HOWEVER THAT ASSUMES DEWPOINTS IN THE 60S. MET/MAV GUIDANCE SEEM MORE REALISTIC WITH DEWPOINTS MAINLY IN THE UPPER 50S WHICH WOULD LOWER CAPE TO AROUND 1000-1500. THIS MAY SEEM A BIT LOW FOR A SIGNIFICANT SEVERE THREAT...HOWEVER THERE SHOULD BE ENOUGH DYNAMICS AND DEEP LAYER SHEAR TO OVERCOME SOMEWHAT LOWER MOISTURE. 0-6 KM BULK SHEAR OF 30-50 KT FORECAST...WITH THE GREATEST VALUES ACROSS SOUTHERN PORTIONS OF THE AREA...SO STORM ORGANIZATION IS ALSO LIKELY. GIVEN EXPECTED STEEP 850-500 MB LAPSE RATES OF CLOSE TO 7C/KM AND LOW FREEZING LEVELS...BOTH WIND AND HAIL WILL BE THREATS. UNLIKE LAST WEEK'S CUT-OFF LOW EVENT...PWAT VALUES FORECAST TO BE SLIGHTLY BELOW NORMAL...WITH PLENTY OF MID LEVEL FLOW...SO FLASH FLOOD THREAT IS LOW. LEANED TOWARDS SLOWER NAM MODEL WITH REGARDS TO EVOLUTION AND PROGRESSION OF THE LOW...WHICH HAS MORE SUPPORT FROM OTHER MODEL GUIDANCE THAN THE GFS. WITH INCREASING CLOUDS AND CONVECTION AROUND...TEMPS ONLY EXPECTED TO RISE INTO THE MID 70S...WITH MID TO UPPER 60S IN THE MOUNTAINS. THE SEVERE THREAT WILL DIMINISH AS THE UPPER JET PUSHES SOUTH AND EAST AWAY FROM THE AREA...AS THE SURFACE OCCLUDED BOUNDARY MOVES INTO NEW ENGLAND. WILL GRADUALLY DECREASE POPS LATER IN THE EVENING AND OVERNIGHT. ON WED...THE CUT-OFF LOW IS FORECAST TO MOVE DIRECTLY OVER THE AREA. HOWEVER...DEEP LAYER SHEAR DECREASES SIGNIFICANTLY AND MOISTURE WILL STILL BE LACKING. STILL...WITH COLD POCKET ALOFT OF -17C TO -19C AT 500 MB...SHOWERS WITH ISOLATED THUNDER COULD PRODUCE SOME SMALL HAIL. WILL LEAN TOWARDS WETTER NAM GUIDANCE AND MENTION LIKELY POPS FOR MOST OF THE AREA. TEMPS WILL CONTINUE TO BE COOL FOR THIS TIME OF YEAR...WITH LOWER 70S TO POSSIBLY MID 70S SOUTH...AND LOWER TO MID 60S ACROSS THE HIGHER TERRAIN. WILL DECREASE POPS ONCE AGAIN WED NIGHT DUE TO LOSS OF DIURNAL HEATING AND THE UPPER LOW STARTS TO PULL AWAY. ON THUR...THE UPPER LOW IS FORECAST TO EXIT EASTWARD OFF THE NEW ENGLAND COAST...HOWEVER WE WILL STILL BE IN CYCLONIC FLOW. WILL MENTION JUST SLIGHT CHANCE POPS AT THIS TIME. WITH MORE SUNSHINE EXPECTED...TEMPS SHOULD WARM INTO THE MID TO UPPER 70S IN MOST AREAS...BUT STILL ABOUT 5 DEGREES BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... HPC GUIDANCE. HIGH PRESSURE IS IN CONTROL AT THE START OF THIS PERIOD...WITH NO MORE THAN SLGT CHC POPS. THEN A COLD FRONT GAINS MOMENTUM AS IS SLIDES SOUTHEAST ACROSS THE GREAT LAKES. SFC CAPES OVER 2000 J/KG AND LIS -5 TO -7 FROM THE CAPITAL REGION N AND W WILL BREED CONDITIONS FAVORABLE FOR CHC TSRA ON SATURDAY...WITH THE ACTIVITY CONTINUING INTO THE OVERNIGHT. THE SOUTHERN ZONES WILL BE MOST FAVORED ON SUNDAY...BUT ACTIVITY MAY BE OVER WITH BY MID AFTERNOON WHEN THE GFS HAS THE FRONT JUST THROUGH OUR ENTIRE FA. THE ECMWF IS SLIGHTLY SLOWER. GFS GIVES ISOLATED QUARTER TO HALF INCH TOTALS WHEREAS ECMWF FOCUSES ON 0.50 INCH PLUS N AND W OF THE CAPITAL DISTRICT. A BRIEF HIGH PRESSURE RIDGE BEFORE A SFC TROF PROVIDES ANOTHER CHC SHRA AS EARLY AS LATE MONDAY. HIGHS TEMPERATURES SLIGHTLY BELOW NORMAL ON FRIDAY TOP OUT IN THE LOW AND MID 80S SATURDAY EXCEPT FOR THE HIGH PEAKS OF THE MOUNTAIN CHAINS. OVERNIGHT LOWS WILL BE WELL BELOW NORMAL THURSDAY NIGHT... BUT NEAR NORMAL FRIDAY...SATURDAY AND SUNDAY NIGHTS...FALLING OFF SLIGHTLY MONDAY NIGHT BEHIND THE TROF. THE MEX ESSENTIALLY IGNORES SUNDAY'S WARM-UP...BUT OTHERWISE HANDLES TRENDS OKAY. IT HAS SLIGHTLY MILDER LOW TEMPS OVERALL. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SHOWERS WIRE DIMINISHING NORTH OF THE AIRPORTS THIS EVENING...BUT INCLUDED VCSH GROUP AT GFL FOR THE FIRST 6 HOURS JUST IN CASE. TS SHOULD NOT BE A CONCERN. GFL SHOULD REACH CROSSOVER TEMP FOR FOG TONIGHT...JUST AS IN PREVIOUS 2 NIGHTS...BUT HAVE THEM STAYING MVFR. OCCASIONAL MVFR FOG IS POSSIBLE AT ALB...IF NOWHERE ELSE SURROUNDING IT. CROSSOVER TEMP IS CLOSE BOTH THERE AND AT POU...WHERE HIGH-END MVFR FOG POSSIBLE. IF CLOUDS FILL IN AS MAV SUGGESTS...LESS FOG. LIS LOW ENOUGH FOR THUNDERSTORM ACTIVITY ON TUESDAY...BUT SOMEWHAT OF A LACK OF HIGH CAPES SUGGESTS PERHAPS A WIDELY SCATTERED EVENT. THUS ATTM HAVE GONE WITH JUST CB INCLUSION AT THE AIRPORTS TUE AFTN. OUTLOOK... TUE NGT-WED...AM IFR FOG POSSIBLE...OTHERWISE VFR...WITH AFTERNOON/EVENING MVFR SHRA/TSRA LIKELY. THU-FRI...VFR...XCP AM MVFR FOG POSSIBLE...NO SIG WX. SAT...MAINLY VFR WITH GOOD CHC SHRA/TSRA. && .FIRE WEATHER... ANOTHER UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION THROUGH WEDNESDAY...BRINGING MORE UNSETTLED WEATHER. MAINLY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH TONIGHT...HOWEVER MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON AND EVENING. WHILE THE TORRENTIAL RAINS WE SAW LAST WEEK ARE NOT EXPECTED...SOME BRIEF HEAVY DOWNPOURS WILL OCCUR. RELATIVE HUMIDITY VALUES WILL RISE TO NEAR 100 PERCENT TONIGHT...THEN DROP TO BETWEEN 50 AND 70 PERCENT ON TUESDAY. RH VALUES WILL INCREASE TO AROUND 100 PERCENT AGAIN TUESDAY NIGHT. WINDS WILL BE LIGHT AND VARIABLE TONIGHT...THEN SHIFT TO THE SOUTHWEST AND INCREASE TO AROUND 5 TO 10 MPH ON TUESDAY. WINDS TUESDAY NIGHT WILL BE WEST AROUND 5 MPH OR LESS. && .HYDROLOGY... ALTHOUGH ANOTHER UPPER LEVEL LOW WILL PLAGUE THE REGION INTO MID WEEK...FLASH FLOOD POTENTIAL LOOKS CONSIDERABLY LOWER THAN LAST WEEK. PRECIPITABLE WATERS THIS MORNING OFF ALY SOUNDING WERE ONE STANDARD DEVIATION BELOW NORMAL. MODELS INDICATE THAT THROUGH THE MIDDLE OF THE WEEK...PWS WILL HOLD AT OR BELOW NORMAL. LAST WEEK PWS EXCEED ONE STANDARD DEVIATION ABOVE NORMAL. BEST CHANCE FOR HEAVY RAINFALL LOOKS TO BE TUESDAY AS BETTER DYNAMICS AND HIGHER DEW POINTS SUGGEST STRONGER TSRA/S IN THE AREA. WHILE ANY ONE STORM CAN DUMP OUT ENOUGH RAIN TO PRODUCE NUISANCE FLOODING...OVERALL THREAT IS AGAIN LOWER THAN LAST WEEK. AS FOR RIVER FLOOD POTENTIAL...DO NOT EXPECT MUCH IN THE WAY OF ANY SIGNIFICANT RESPONSE AS RIVERS HAVE HAD A CHANCE TO RECEDE FOLLOWING LAST WEEK/S HEAVY PRECIP. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...JPV NEAR TERM...JPV SHORT TERM...JPV LONG TERM... AVIATION...ELH FIRE WEATHER... HYDROLOGY...OKEEFE