817 
fxus61 kbgm 061414 
afdbgm 


Area forecast discussion 
National Weather Service Binghamton New York 
1014 am EDT Sat Sep 6 2008 


Synopsis... 
Tropical Storm Hanna will move north along the East Coast today. 
Heavy rain will move into northeast Pennsylvania and the Catskills 
of New York this afternoon and evening. The rainfall is expected 
to come to an end Sunday morning. High pressure with dry weather 
will be across the region late Sunday into Monday. 


&& 


Near term /until noon today/... 
as of 1015 am EDT... 
Tropical Storm Hanna looks to be located along the NC/Virginia border 
and is still heading off to the north. Still waiting to see if 
Hanna will continue heading north...but it looks as if it may be 
slowly beginning to head northeast. Either way...a big area of 
rain is moving into S-central and sepa and is heading up into nepa. 
This area of rain should mv in within the next hour. Models still hvg 
trouble with this area of rain with the 06z NAM indicating very 
little quantitative precipitation forecast this far north already. The GFS is also not catching 
onto the northward extent of the precipitation shield. 


Latest RUC has a pretty good handle on precipitation with it located just 
south of County Warning Area at 14z. In turn it is also further west than the 
other models indicate and gives more rain to southeastern zones. In 
recognition of the fact that most of the precipitation is to the north and 
west of the center as expected and the storm continues to mv north-NE 
will keep Flood Watch as is. There will be a very tight gradient 
of 1 inch to 5 inches and this could fall on either side of the County Warning Area 
boundary. This will be a close one for our southeastern zones. Feeling is 
that somewhere in the southern part of the Flood Watch area will likely 
see heavy rain before the day is out with flooding problems. Stay tuned... 


As for the winds...highest gusts have been confined along the 
coast...immediately east of the center. Klwx VAD wind profiles 
indicate only 25-30kts off the surface. Thus...will leave things as is 
with gusty winds mentioned in the severe weather potential statement for the Poconos but no wind 
advisories at this time. RUC 800 mb winds only forecast to be around 
20-25kts at 2kft. It will be close to advisory criteria but 
confidence is still not there for any widespread problems from 
winds this afternoon. 


Previous discussion... 
first west to east area of rain is lifting through the County Warning Area at this time. 
This is well ahead of Hanna and the heavier rain that is expected 
this afternoon and evening. This first batch should be handled easily even 
with an area of 1 inch radar rainfall estimates in the Catskills. 
It has been dry for the past week with 1 hour ffg over 2 inches. 


&& 


Short term /noon today through Monday night/... 
Flood Watch continues for the same area. Models have pushed the 
heavy rain axis back to the east. Only Pike and Sullivan are 
forecasted to get basin average amounts over 2 inches. Do not want 
to change again since another shift back to the west is possible. 
Very sharp gradient between less than 1 inch and over 3 inches. 
With ample tropical moisture and precipitable waters  over 2 inches with warm 
cloud depths to 14k feet rainfall rates will be over 1 inch an hour. 
Right rear quadrant of ul jet will also help with deep lift. Models in 
agreement of placement of SW to NE heavy rain axis along southeast County Warning Area 
border. With the dry ground due to the lack of rain so far this 
month any flooding will be this afternoon on. Rivers are at 
seasonally low values. It will take over 3 inches for even the 
headwaters to flood. Biggest flood threat will be flash flooding 
of creeks...smaller streams...and urban areas. The main Stem of 
the Delaware will show significant rises but remain well below 
flood stage. The NYC reservoirs will hold all the rain. 


With heavy rain at the time of the best ll jet do not see much 
widespread downward translation. Highest elevations in the Poconos 
closest to the track of Hanna could see some gusts into the 30s 
for a brief time around 00z. Storm track will be east of County Warning Area with 
forward acceleration. Higher winds will have trouble getting onto 
the back side of the storm this far inland. 


Precipitation should clear out late Sat night/early Sun morning...lvg clrng 
skies and above normal temperatures as weak high pressure builds in. 


A cold front approaches from the west Monday afternoon and night 
but little forcing gets into the County Warning Area until Tuesday. Have chance probability of precipitation 
mostly for the northwest half of the County Warning Area. A surface wave could form as a 
strong vorticity waves moves east with a ul trough. 


&& 


Long term /Tuesday through Friday/... 
just some minor adjacent to current forecast. Will continue with chance 
probability of precipitation Tuesday into Tuesday evening due to cold frontal passage. Frontal passage timing 
late week shows European model (ecmwf) faster than GFS, will continue with chance probability of precipitation Thursday 
night through Friday night due to timing differences. 


Previous disc... 
weak upper trough digging in for Tuesday with surface cold front will 
bring chance for precipitation late Monday and Tuesday, as the boundary 
slides southeast. Then, surface high pressure looks like it will 
provide fair weather for middle week before next front approaches. 
Some timing diffs between European model (ecmwf) and GFS on whether precipitation will 
arrive Thursday or Friday. Since new European model (ecmwf) arrives too late for 
this pkg, will lean somewhat more toward the GFS for now. May need to 
adjust timing for this feature later. 


&& 


Aviation /14z Saturday through Wednesday/... 
initial band of precipitation from remnants of ts Hanna lifting into northern 
portion of County Warning Area at 11z. Flight restrictions will lower to MVFR as this 
band sweeps over terminals with MVFR ceilings continuing after precipitation 
ends. 


Second more significant batch of rain from tropical system will 
impact southern/central terminals this afternoon through early evening. 
Again MVFR restrictions with brief IFR in any heavier convective 
elements. Conditions will gradually improve overnight. 


Southeast winds 5-10 knots becoming north/northwest this evening and 
overnight. At this time no significant wind issues expected at taf sites. 


Outlook... 


Sunday to Monday...VFR. Some early morning restrictions in fog 
most likely at Elm. Other locations could fall to MVFR visibilities due 
to wet ground and good radiational cooling. 


Monday night to Tuesday...next front approaches late Monday night with 
MVFR restrictions in showers and possibly thunder along boundary 
Tuesday. 


Wednesday...VFR. Restrictions possible in morning fog especially 
at Elmira. 


&& 


Equipment... 
thanks to a tremendously dedicated team of electronics experts...the 
kbgm WSR- 88D began spinning again around midnight. This was done 
in record time of just under four days with a tropical storm 
looming. 


The radar is down for several hours this morning for calibration 
and testing. However...it should be back up in time for the bulk of the 
heavy precipitation associated with ts Hanna. All users should still use caution 
when using precipitation products...as it will not capture the storm total 
precipitation after being down for several hours this morning. Please refer to 
surrounding radars (kenx...ktyx...kbuf...kdix...kokx and kccx) for 
the most up to date images and estimated precipitation amounts. Will update 
the status as information becomes available. 


&& 


Bgm watches/warnings/advisories... 
PA...Flood Watch through Sunday morning for paz039-040-043-044-047- 
048-072. 
New York...Flood Watch through Sunday morning for nyz057-062. 


&& 


$$ 
Synopsis...tac 
near term...pb/tac 
short term...tac 
long term...jml/rrm 
aviation...rrm 
equipment...pb 

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