Ian

I'm going to upload images the next few days from when I saved them. Plz feel free to share similar as you wish! Feb 1 Feb 2

too bad i wont be here all night. wtf happened? oh wait.

look west!

it's coming!

12z GFS Ensemble mean 12/18/09

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 439 PM EST FRI DEC 18 2009 VALID 00Z SAT DEC 19 2009 - 00Z TUE DEC 22 2009 DAY 1... MID ATLANTIC STATES AND CENTRAL APPALACHIANS AN AREA OF LOW PRESSURE OVER THE SOUTHEAST US WILL BE INTENSIFYING/DEEPENING AS IT MOVES NORTHEAST TO JUST OFF THE OUTER BANKS OF NORTH CAROLINA 12Z SAT AND ROUGHLY 150NM EAST OF THE DELMARVA SAT EVENING. THE PRECIPITATION SHIELD HAS MOVED STEADILY NORTH AND IS MOVING/EXPANDING NORTH A FEW HOURS FASTER THAN FORECAST YESTERDAY AND ALSO BY TODAYS 12Z MODELS. THE MODELS ARE SHOWING WELL DEFINED DIVERGENCE ASSOCIATED WITH THE ENTRANCE REGION OF AN UPPER LEVEL JET AND COUPLED JET THAT LIFTS NORTH ACROSS THE CENTRAL APPALACHIANS TO THE MID ATLANTIC REGION AND TOWARDS SOUTHEAST NY SATURDAY EVENING. WIND SPEEDS IN THE JET CORE ACCELERATE FROM AROUND 120 KTS EARLY ON INTO THE 150-170 KT IN THE 15Z SREF MEAN. THIS LEADS TO A COMBINATION OF LARGE LOW TO MID LEVEL MOISTURE FLUXES AND CONVERGENCE LEADING TO WIDESPREAD MODERATE TO HEAVY SNOW. UPSLOPE FLOW WILL ENHANCE SNOW AMOUNTS IN THE EAST SIDE OF THE APPALACHIANS FROM VIRGINIA NORTHWARD. THE MODELS STILL HAVE SIGNIFICANT SPREAD ALTHOUGH ALL OF THE NAM/ECMWF/SREF MEAN/GEFS MEAN/GFS/CANADIAN GLOBAL/UKMET SOLUTIONS ALL SHOW HEAVY SNOW WITH POTENTIAL UP TO TWO FEET IN THE CONSENSUS OF THESE SOLUTIONS IN PORTIONS OF CENTRAL VA...WHICH WOULD BE RECORD SNOW FOR MANY AREAS. HEAVY SNOW EXTENDS ACROSS THE BALTIMORE AND WASHINGTON AREAS UP TO SOUTHERN NJ SAT. MANUAL PROGS USED A BLEND OF THE 12Z NAM/12Z GFS/12Z UKMET/09Z-15Z SREF MEAN/12Z GEFS MEAN/00Z ECMWF TO MITIGATE DIFFERENCES AMONG SOLUTIONS. CONFIDENCE IS LOW IN THE 12Z ECMWF TREND TO LOWER AMOUNTS GIVEN ITS FAVORABLE COUPLED 300 MB JET WITH SUSTAINED DIVERGENCE IN THE CORRIDOR FROM WV ACROSS VA/MD. FREEZING RAIN AND/OR ICE PELLETS ARE EXPECTED ACROSS CENTRAL NC SINCE FORECAST SOUNDINGS NOW SHOW A DEFINED INVERSION ALOFT BETWEEN 800-700 MB ABV FREEZING WHICH SHOULD MELT FALLING SNOW FOR A PERIOD OF SEVERAL HOURS TONIGHT BEFORE THE LOW PASSES AND THE INVERSION ERODES AND PRECIP TAPERS OFF. DAY 2... NJ/NY/SRN NEW ENGLAND... THE LOW TO MID LEVEL CYCLONE SHOULD BE TRACKING NORTHEAST ON DAY TWO...WITH ASCENT ACROSS LONG ISLAND/SOUTHERN NEW ENGLAND AS THE BROAD LEFT EXIT REGION PROVIDES A BROAD AREA OF UPPER DIVERGENCE AND SUPPORTS LOW LEVEL MOISTURE ASCENDING INTO THE LOW LEVEL COLD AIR. WITH THE MODELS STARTING TO CONVERGE ON SOLUTIONS..AS THE FARTHER WEST 12Z NAM TRENDED EAST AND THE FARTHER EAST 00Z GFS TRENDED WEST ON THE 12Z RUN WITH ITS LOW POSITIONS AND TRACK. THE SPREAD HAS NARROWED TO A NORMAL RANGE OF TIMING/AMPLITUDE DIFFERENCES. THE 12Z-18Z NAM IS ON THE SLOW SIDE OF THE MODEL/ENSEMBLE SOLUTIONS. PRECIPITATION GRADIENTS ARE SHARP...SO THE FULL RANGE OF PROBABILITIES ARE USED AS THE 12Z GEFS MEAN/ 09-15Z SREF MEAN/18Z NAM SUPPORT POTENTIAL FOR A FOOT OF SNOW OVER LONG ISLAND AND SOUTHEAST NEW ENGLAND. THE 12Z ECMWF HAS NUDGED ITS QPF HIGHER THAN THE 00Z RUN DUE A SUSTAINED UPPER LEVEL DIVERGENCE MAXIMA DOWNSTREAM FROM THE 300 MB CIRCULATION CENTER. MANUAL PROGS BLENDED THE 12Z NAM/12Z GFS/09Z-15Z SREFMEAN/12Z GEFS MEAN/12Z ECMWF. PACIFIC NORTHWEST/NORTHERN ROCKIES... MOIST ONSHORE FLOW AHEAD OF AN AREA OF LOW PRESSURE OVER THE ERN NOPAC SHOULD COMBINE WITH UPPER DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A JET STREAK CROSSING THE US CANADIAN BORDER TO PRODUCE ASCENT IN THE RANGES OF WA INTO THE NORTHERN ROCKIES. LOW TO MID LEVEL WARM ADVECTION AIDS ASCENT BUT ALSO COMPLICATES THE FORECAST DUE TO RISING SNOW LEVELS WITH TIME. A RISK OF 4 TO 8 INCHES OF SNOW IS EXPECTED MAINLY IN THE HIGHER ELEVATIONS OF THE CASCADES TONIGHT...AND THEN INTO THE NORTHERN ROCKIES AFTERWARD. PARTS OF THE WA CASCADES HAVE A THREAT OF A PERIOD OF FREEZING RAIN AS THE WARM ADVECTION MAY PRODUCE WARMING ABV FREEZING ALOFT FIRST BEFORE SCOURING OUT THE SFC SUB FREEZING AIR WHERE COLD AIR PERSISTS. DAY 3... PACIFIC NORTHWEST/NORTHERN ROCKIES... THE MODELS ARE IN AGREEMENT IN AMPLIFYING THE MID-UPPER LEVEL TROUGH AS IT MOVES SLOWLY FROM THE EASTERN PACIFIC TOWARDS THE PACIFIC NORTHWEST. THE DOWNSTREAM UPPER LEVEL JET MOVES ONSHORE ACROSS OREGON INTO ID AND THEN MT. DIVERGENCE IN THE DIFLUENT FLOW FURTHER NORTH SUPPORTS ASCENT COMING ACROSS THE WA CASCADES INTO THE NORTHERN ROCKIES. SUSTAINED DEEP LAYER SOUTHWEST FLOW FAVORS HEAVIER SNOW AT HIGHER LEVELS OF THE WA CASCADES. THE SOUTHWEST FLOW THEN PROGRESSES INLAND INTO THE RANGES OF ID AND WESTERN MT/NORTHWEST MY. TIMING DIFFERENCES AMONG THE MODELS GROW...AND EVENT THE EVOLUTION OF THE MID-UPPER LEVEL SHORTWAVES VARIES AMONG MODEL SOLUTIONS. A GROWING SPREAD OF FORECAST QPF RESULTS WITH THE 12Z ECMWF ON THE LIGHT END OF THE SPECTRUM AND 09-15Z SREF MEAN ON THE HEAVIER END. MANUAL PROGS BLENDED SOLUTIONS TO FIND A CONSENSUS...AND LEFT OPEN AREAS OF MOSTLY LOW-MDT SNOW PROBABILITIES...WITH HIGH 4 INCH PROBABILITIES OVER THE CASCADES WITH THE MOST AGREED UPON HIGHER QPF AND FAVORABLE DEEP LAYER MOISTURE PROFILES. THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT. PETERSEN

MESOSCALE DISCUSSION 2258 NWS STORM PREDICTION CENTER NORMAN OK 0622 PM CST FRI DEC 18 2009 AREAS AFFECTED...PORTIONS OF THE CNTRL/SRN APPALACHIANS AND LOWER MID-ATLANTIC CONCERNING...HEAVY SNOW VALID 190022Z - 190515Z HEAVY SNOW WITH RATES OF 1 TO 2 IN/HR WILL GRADUALLY TRANSLATE E/NEWD THROUGH 06Z...TOWARDS THE I-95 CORRIDOR FROM THE WASHINGTON D.C. TO RICHMOND METRO AREAS. LOCALIZED CONVECTIVE BURSTS MAY YIELD RATES UP TO 3 IN/HR. A NARROW TRANSITIONAL CORRIDOR OF SLEET TO FREEZING RAIN MAY DEVELOP ACROSS PORTIONS OF THE PIEDMONT IN WRN NC TO S-CNTRL VA. AS OF 0015Z...A BROAD SWATH OF MODERATE TO HEAVY SNOW PERSISTED FROM PORTIONS OF THE CNTRL/SRN APPALACHIANS INTO THE PIEDMONT OF WRN NC AND CNTRL/SRN VA. MULTIPLE HOURS OF SNOWFALL RATES FROM 1 TO 2 IN/HR HAVE BEEN REPORTED SINCE 21Z ACROSS FAR ERN TN/KY...WRN NC AND SWRN VA. LATEST MODEL FORECASTS ARE CONSISTENT WITH WEAKENING THE LEAD SHORT WAVE TROUGH...WHICH EXTENDED FROM ERN TN/KY SWD INTO GA PER WATER VAPOR IMAGERY. NEVERTHELESS...UPSTREAM SHORT WAVE TROUGH OVER THE MID-MS VALLEY AND ASSOCIATED MID-LEVEL JET ARE EXPECTED TO AMPLIFY AS THEY EJECT EWD ACROSS THE TN VALLEY. THIS WILL MAINTAIN GRADUAL DEEPENING OF SURFACE CYCLONE ALONG COASTAL SC THROUGH 06Z. STRONG LOW-LEVEL WAA...INFERRED BY LARGE VEERED HODOGRAPHS IN REGIONAL VWP DATA...SHOULD CONTINUE AS 18Z NAM/21Z RUC FORECASTS DEPICT INTENSE LOW/MID-LEVEL ISENTROPIC/FRONTOGENETICAL ASCENT GRADUALLY PIVOTING EWD TO THE N/NW OF THE SURFACE LOW TRACK. THIS WILL SUPPORT SNOWFALL RATES OF 1 TO 2 IN/HR PERSISTING...WHILE THE STRENGTH OF THE WAA MAY RESULT IN A NARROW CORRIDOR OF SLEET TO FREEZING RAIN ACROSS PORTIONS OF WRN NC INTO S-CNTRL VA. ..GRAMS.. 12/19/2009 ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...AKQ...LWX...RAH...RNK...PBZ...RLX...GSP...MRX... JKL... LAT...LON 38538173 38038263 37288338 36518351 36268282 36228199 35808150 35768061 35917987 36147945 36877738 37467624 38297615 39027688 39257777 39107915 38858058 38538173 MESOSCALE DISCUSSION 2259 NWS STORM PREDICTION CENTER NORMAN OK 1134 PM CST FRI DEC 18 2009 AREAS AFFECTED...PORTIONS OF THE CNTRL APPALACHIANS AND LOWER MID-ATLANTIC CONCERNING...HEAVY SNOW VALID 190534Z - 191100Z HEAVY SNOW WILL SLOWLY TRANSLATE E/NEWD FROM ERN KY/SRN WV/NRN AND CNTRL VA INTO MD/DE AND SRN NJ/PA BY 12Z. SNOWFALL RATES OF 1 TO 2 IN/HR WILL REMAIN COMMON...WITH MOST PERSISTENT DURATION OF HEAVIER RATES LIKELY LYING ALONG THE WV/VA BORDER EWD TO THE I-95 CORRIDOR OF THE WASHINGTON D.C./BALTIMORE METRO AREAS. AS OF 0530Z...RADAR/SURFACE OBSERVATIONS DEPICT A SWATH OF MODERATE TO HEAVY SNOW FROM ERN KY EWD ACROSS THE CNTRL APPALACHIANS TO THE I-95 CORRIDOR FROM DCA TO RIC. A MID-LEVEL DRY SLOT /EVIDENT IN WATER VAPOR IMAGERY/ HAD EFFECTIVELY ENDED HEAVIER SNOW ACROSS WRN NC AND FAR ERN TN/SWRN VA...MORE QUICKLY THAN INDICTED IN 00Z NAM/HI-RES WRF-NMM/GFS FORECASTS. 03Z RUC GUIDANCE SUGGESTS THIS DRY SLOT WILL OVERSPREAD MUCH OF CNTRL/SRN VA THROUGH 12Z...RESULTING IN SIGNIFICANT DRYING OF THE DENDRITIC GROWTH LAYER. THUS...THE AXIS OF HEAVIER SNOWFALL RATES MAY NOT LIE AS FAR SOUTH AS CONSENSUS OF MODEL QPF/SREF SNOWFALL GUIDANCE WOULD INDICATE. EVEN SO...CONTINUED GRADUAL DEEPENING OF A SURFACE CYCLONE TRACKING ALONG THE NC COAST WILL MAINTAIN STRONG LOW/MID-TROPOSPHERIC ISENTROPIC AND FRONTOGENETICAL ASCENT ACROSS THE LOWER MID-ATLANTIC REGION. THIS WILL SUPPORT PERSISTENT 1 TO 2 IN/HR SNOWFALL RATES TO THE N OF THE IMPINGING DRY SLOT. ..GRAMS.. 12/19/2009 ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...PBZ...RLX...MRX... JKL... LAT...LON 39967520 39477481 38437555 37217752 37117889 37447996 37498123 37188246 37138329 37738322 38608156 39297967 39937836 40087619 39967520 MESOSCALE DISCUSSION 2260 NWS STORM PREDICTION CENTER NORMAN OK 0557 AM CST SAT DEC 19 2009 AREAS AFFECTED...ERN WV...NRN VA...MD...DE...SERN PA...NJ CONCERNING...HEAVY SNOW VALID 191157Z - 191800Z BANDS OF HEAVY SNOW WITH RATES OF 1-2 IN/HR WILL PERSIST MAINLY FROM ERN WV ACROSS NRN VA AND MD...DE...SERN PA AND SRN NJ. THE LONGEST DURATION OF HEAVY SNOW RATES IS LIKELY TO BE OVER ERN WV...NRN VA...AND MUCH OF MD. A LARGE SHIELD OF SNOW CURRENTLY EXTENDS FROM NEAR THE UPPER LOW CENTER OVER WV EWD N OF A DEEPENING SURFACE LOW. WARM ADVECTION COUPLED WITH DEEP LAYER FRONTOGENESIS IS RESULTING IN PERSISTENT AND MULTIPLE W-E BANDS OF HEAVY SNOW. DUE TO THE SLOW MOVEMENT OF THE TROUGH...LONG DURATIONS OF HEAVY SNOW WILL OCCUR. THROUGH 18Z...EXPECT A SLIGHT PIVOT OF THE SNOW BANDS TO A WSW-ENE ORIENTATION AS THE LOW LEVEL WINDS BACK A BIT. BROAD...PERSISTENT FRONTOGENESIS SHOULD RESULT IN FURTHER CONSOLIDATION OF THE SNOW BANDS OVER THE MCD AREA. AS THE UPPER LOW PIVOTS EWD...COOLING ALOFT MAINLY ABOVE 650 MB WILL RESULT IN A DEEPER DENDRITIC GROWTH LAYER YIELDING A MORE TEMPERATURE PROFILE FOR PARTICULARLY HEAVY SNOW FROM 12-18Z ACROSS ERN WV...NRN VA...AND CNTRL MD. SNOW RATES COULD INCREASE TO MORE THAN 2 IN/HR AT TIMES. ..JEWELL.. 12/19/2009 ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OKX...PHI...AKQ...CTP...LWX...RNK...PBZ...RLX... LAT...LON 37787819 37668022 38068133 39008107 39627971 40377822 40597660 40617420 39997393 38987476 38347589 37787819 MESOSCALE DISCUSSION 2261 NWS STORM PREDICTION CENTER NORMAN OK 1127 AM CST SAT DEC 19 2009 AREAS AFFECTED...VA...WV...MD...DE...NJ...PA...NY...CT CONCERNING...BLIZZARD VALID 191727Z - 192330Z HEAVY SNOWFALL RATES OF 1-3 INCHES PER HOUR ARE LIKELY FROM THE D.C. I-95 CORRIDOR NNEWD TOWARDS LONG ISLAND THIS AFTERNOON. WITHIN THIS ZONE...BLIZZARD-LIKE CONDITIONS WILL LIKELY AFFECT PORTIONS OF THE MEGALOPOLIS. CENTER OF MAJOR EAST COAST CYCLONE/BOMB WILL MAKE GRADUAL NNEWD PROGRESS FROM EAST OF VA CAPES TO SOUTHEAST OF CAPE MAY NJ THROUGH EVENING WHILE UNDERGOING SUBSTANTIAL DEEPENING. STRONGEST ASCENT...AND GREATEST HOURLY SNOWFALL RATES...WILL COINCIDE WITH MOST INTENSE 850-700MB FRONTOGENESIS AND DEEPEST DENDRITE GROWTH LAYER. LATEST NCEP-SREF GUIDANCE THROUGH 00Z SHOWS THESE DYNAMIC AND THERMODYNAMIC FEATURES WILL TRANSITION ONLY SLOWLY NWD/NWWD THROUGH LATE TODAY. BROAD AND QUASI-BANDED HEAVY SNOW FIELD SHOULD GRADUALLY DECAY ON ITS SWRN FLANK...AND DEVELOP/INTENSIFY AND PIVOT COUNTERCLOCKWISE FROM NRN MD/SERN PA TO SOUTH SHORE OF LONG ISLAND THROUGH LATER THIS AFTERNOON. SREF PROBABILITY MATCHED-MEAN /PMM/ 3-HOUR SNOWFALL TOTALS WERE USED TO ARRIVE AT THE 1-2 INCH AND 2 INCH PLUS PER HOUR RATES DEPICTED IN THE MD GRAPHIC. FURTHERMORE...AS BOMBOGENESIS OCCURS OFFSHORE...THE INCREASING PRESSURE GRADIENT WILL LEAD TO STRONG WINDS AOA 35 MPH FROM DELMARVA NWD TOWARDS LONG ISLAND. THIS IS SUPPORTED BY THE 00Z NSSL 4 KM WRF SHOWING MAX 1 HOURLY WINDS BETWEEN 30-40 KTS OVER THIS CORRIDOR. THUS...CONSIDERABLE FALLING...BLOWING...AND DRIFTING SNOW WILL RESULT IN BLIZZARD CONDITIONS WITH VISIBILITIES NEAR ZERO IN THE HEAVIEST SNOW BURSTS. ..SMITH/CARBIN.. 12/19/2009 ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OKX...PHI...BGM...AKQ...CTP...LWX... LAT...LON 39127892 40467719 40917595 41227425 41117293 40697292 39697441 38617598 38537640 38207695 38337796 39127892 http://spc.noaa.gov/products/md/2009/md2262.html http://spc.noaa.gov/products/md/2009/md2263.html

I remember talking to zwyts (Matt) during the early afternoon on the phone while I was out walking around. He had told me stories about the city in a big storm but this was really my first experience. I did get here right before the Feb 2006 storm but it happened at night, melted quick, and I had just arrived from New England so I barely paid attention to it. I just remember wandering local streets that are otherwise kind of mundane and being in awe of how much snow was on the ground here in the city and that everything basically came to a complete halt. It was maybe a bit before this time I tried to just take it all in as much as possible but I feel like I didn't have enough time. Who knew more was coming later..

Jason's post on CWG made me figure I might as well copy him... http://voices.washin..._of_snowpo.html SLP 500mb LWX SNOW MAP RADAR