NEG NAO Posted November 29, 2013 Share Posted November 29, 2013 EXTENDED FORECAST DISCUSSIONNWS WEATHER PREDICTION CENTER COLLEGE PARK MD154 AM EST FRI NOV 29 2013VALID 12Z MON DEC 02 2013 - 12Z FRI DEC 06 2013...PATTERN OVERVIEW WITH MODEL/UNCERTAINTY ASSESSMENT AND SENSIBLEWEATHER HIGHLIGHTS...GUIDANCE OFFERS GREATER THAN NORMAL FORECAST SPREAD ANDUNCERTAINTY EARLY NEXT WEEK WITH THE HANDLING OF MID-UPPER LEVELIMPULSE ENERGY PROGRESSING SEWD FROM THE CENTRAL TO ERN US. THESE EMBEDDED FEATURES IN RELATIVE LOW AMPLITUDE FLOW HAVE BEENDEPICTED QUITE INCONSISTENTLY FROM RUN TO RUN WITH BOTH FOCUS ANDTIMING EVEN AT THESE RELATIVELY SHORT TIME FRAMES...BUT WITH THEREGION WITHIN AN OVERALL COLLAPSING HEIGHT FIELD WITH PASSAGE. AMID UNCERTAINTY ALOFT...A NEAR COMPOSITE SOLUTION WOULD FAVORSOME COLD AIR INTRUSION AND SPURTS OF COLD SEASON PCPN ACROSS THEEAST-CENTRAL US ALONG WITH POSSIBLE ENHANCEMENT FROM MODEST SEUS/MID-ATLANTIC TO OFF NEW ENG COASTAL LOW GENESIS. FORECAST SPREAD ALOFT AND UNCERTAINTY SEEMS LESS UPSTREAM FROM THEPACIFIC AND ALASKA INTO THE WRN US...ACTUALLY EVEN AT LONGER TIMESFRAMES INTO LATE NEXT WEEK. STRONG FLOW AMPLIFICATION ACROSS THEEAST-CENTRAL PACIFIC COMMON TO GUIDANCE LEADS TO SIGNIFICANTMID-UPPER LEVEL RIDGE BUILDING UP INTO ALASKA AND AMPLE ANDDOWNSTREAM TROUGH AMPLIFICATION AND COLDER TEMPS DOWN ACROSS THEENTIRE WRN US/ROCKIES NEXT WEEK...ALONG WITH A GOOD SWATH OFWINTER PCPN SHIFTING SEWD ACROSS THE WEST AS FURTHER ENHANCEDLOCALLY WITH FAVORED TERRAIN/UPSLOPE. LARGER MODEL DIFFERENCESBECOME MORE EVIDENT AT LOWER LEVELS WITH SPECIFICS OF COLD AIRSURGES AND LEAD LOW GENESIS MID-LATER NEXT WEEK THAT SPILL OUTTHROUGH S-CENTRAL CANADA AND THE CENTRAL TO EAST-CENTRAL US. INCREASING GULF MOISTURE INFLOW INTO/AHEAD OF A COMPLEX FRONTALSTRUCTURE WOULD FAVOR AN EMERGING LEAD RAINFALL PATTERN ANDWARMING TEMPS INTO LATE NEXT WEEK...BUT ALSO SOME WINTER PCPNPOTENTIAL ON THE NW PERIPHERY OF THE OVERALL PCPN SHIELD IN ANAMPLIFYING PATTERN.OVERALL...THE WPC MEDIUM RANGE GUIDANCE SUITE WAS PRIMARILYDERIVED FROM A 50-50 BLEND OF REASONABLY COMPATABLE GUIDANCE FROMTHE 18 UTC GFS ENSEMBLE MEAN AND 12 UTC ECMWF ENSEMBLE MEAN IN ANEFFORT KEEP EMPHASIS ON THE MOST PREDICTABLE FORECAST COMPONENTSWHILE MINIMIZING ERROR AND ESPECIALLY RUN TO RUN FORECAST VARIANCEINSTEAD OF CHASING MORE DETERMINISTIC MODEL OPTIONS.SCHICHTEL Link to comment Share on other sites More sharing options...
weathermedic Posted November 29, 2013 Share Posted November 29, 2013 GFS came around (once again) to EC and is showing a coastal low next week. Again, the question is, how close does it get. At least we have something to track over the next few days. Let's see what the models do with it. Link to comment Share on other sites More sharing options...
supermeh Posted November 29, 2013 Share Posted November 29, 2013 Second run in a row the gfs likes tuesday Link to comment Share on other sites More sharing options...
PB GFI Posted November 29, 2013 Share Posted November 29, 2013 12z GFS gets to yesterdays 12z Euro . For coastal interests , it will come down to rates - 850`s are minus 1 , the winds are NORTH this time , not East so rates will cool BL . " if " this track is right 4 days out . Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted November 29, 2013 Share Posted November 29, 2013 Just a quick post, new to the forum... Have been following for many years and was a long time member of NYCmetro looking for some new thoughts... Hope everyone's thanksgiving was well Link to comment Share on other sites More sharing options...
NEG NAO Posted November 29, 2013 Author Share Posted November 29, 2013 Just a quick post, new to the forum... Have been following for many years and was a long time member of NYCmetro looking for some new thoughts... Hope everyone's thanksgiving was well Welcome aboard again - what are your thoughts on this possible event ? Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted November 29, 2013 Share Posted November 29, 2013 As far this particular event I think the chances for snow will be shot as long as the SW flow and the SE Ridge are amped coupled with a -pna and +nao.. If anything falls IMO it will be rain Link to comment Share on other sites More sharing options...
Wxoutlooksblog Posted November 29, 2013 Share Posted November 29, 2013 12z GFS gets to yesterdays 12z Euro . For coastal interests , it will come down to rates - 850`s are minus 1 , the winds are NORTH this time , not East so rates will cool BL . " if " this track is right 4 days out . There's really no cold air left. As you say, it would have to do it on dynamics, and even then, chances of any significant accumulation are extremely slim. WX/PT Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted November 29, 2013 Share Posted November 29, 2013 Euro has no storm Sent from my SAMSUNG-SGH-I747 using Tapatalk Link to comment Share on other sites More sharing options...
Heisy Posted November 29, 2013 Share Posted November 29, 2013 Euro has no storm Sent from my SAMSUNG-SGH-I747 It does have a storm, just weak and develops late. Link to comment Share on other sites More sharing options...
Heisy Posted November 29, 2013 Share Posted November 29, 2013 Just for kicks, but the 12z NAM extrapolated (don't hate), would probably be a bomb. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted November 29, 2013 Share Posted November 29, 2013 Looks like the ECM has the storm system but from the track it would keep it out to sea ..which is what the majority of GFS ensemble members do as well.. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted November 29, 2013 Share Posted November 29, 2013 If u look at the 18z nam at 84 hrs @ 500mb it sure looks like there is phasing happening with a severely negative tilted trof with ample energy pouring into the backside of said trof. Screams coastal storm or just offshore no? Sent from my SAMSUNG-SGH-I747 using Tapatalk Link to comment Share on other sites More sharing options...
Heisy Posted November 29, 2013 Share Posted November 29, 2013 Yea 18z NAM would probably be a huge noreaster, well see what DGEX shows, but obviously its only for fun in that time range with that model. Link to comment Share on other sites More sharing options...
TauntonBlizzard2013 Posted November 29, 2013 Share Posted November 29, 2013 Yea 18z NAM would probably be a huge noreaster, well see what DGEX shows, but obviously its only for fun in that time range with that model. The pattern is in w transition phase at that time. Perfect time for a big storm. That for sure helps our chances here is say Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted November 29, 2013 Share Posted November 29, 2013 Its a damn shame bl is warm and we are working with a dying stale cold-air mass with this potential. Btw hope you folks don't mind me posting in this subforum...the phl one is a dead zone. I will keep it on-point. Sent from my SAMSUNG-SGH-I747 using Tapatalk Link to comment Share on other sites More sharing options...
PB GFI Posted November 29, 2013 Share Posted November 29, 2013 This is looking ok for you guys away from the coast. The coastal plain just can't hold the cold air. It's just not the pattern right for it yet Link to comment Share on other sites More sharing options...
Sundog Posted November 29, 2013 Share Posted November 29, 2013 This is looking ok for you guys away from the coast. The coastal plain just can't hold the cold air. It's just not the pattern right for it yet We should have north winds though so I wouldn't discount the whole system yet at this range, if there even is a storm to begin with. Link to comment Share on other sites More sharing options...
Metsfan Posted November 29, 2013 Share Posted November 29, 2013 18z still develops a storm, however compared to 12z it is weaker and warmer, because of less phasing with energy. Link to comment Share on other sites More sharing options...
PB GFI Posted November 29, 2013 Share Posted November 29, 2013 We should have north winds though so I wouldn't discount the whole system yet at this range, if there even is a storm to begin with. Yes the winds are northeast in ths set up however now 850s are plus 1 or 2. Not minus 1 so the column isn't cold. Hard enough to overcome a bad BL without good precip rates. But if the mid levels are warm then we rain. Can we change over sure. But I thnk those details are 4 days out Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted November 29, 2013 Share Posted November 29, 2013 Just for kicks, but the 12z NAM extrapolated (don't hate), would probably be a bomb. NAMs always exaggerated especially in terms of Qpf lol Link to comment Share on other sites More sharing options...
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