Central PA thread - Spring-like weather now, but...

[canderson]

Anyone in the HBG area wanna throw a hurricane party?

[EasternUSWX]

Sandy means business

Hello all, Sandy continues to move northward tonight with winds just above hurricane force at 75mph, with higher gusts. Overall, the storm is exhibiting characteristics much like those of an extratropical cyclone, and as labeled by the National Hurricane Center earlier today, the transition is already under way. The storm, which was previously moving northward at quite a fast pace through the southern and further north into the central Bahamas has slowed significantly, and came almost to a temporary stall off the coast of Florida. The winds, which as stated are at 75mph now, should continue to press northward at a slower pace, 7-12mph. The storm looks the way it does now because of wind shear that is displacing the center of circulation from the convection, though this situation is something not uncharacteristic for storms like Sandy, especially those transitioning into a hybrid or extratropical cyclone. The storm should continue on that northerly heading as described for the next few days, with a jog to the east occurring Sunday. Though the storm will be off Cape Hatteras by that time, clouds associated with the storm, and even showers will begin impacting the area on Sunday morning with the best chances for rain coming to southeast areas Sunday evening. Sunday will be the least impact many see from Sandy, with Monday and Tuesday beng the days where the brunt of the effects are felt. Many are worried and are bringing up situations like Isabel or Irene in terms of impact. In relation to those storms, there are ways to compare Sandy or its hybrid low that could surprise certain people. For those in places west of the Chesapeake Bay in Maryland, the storm surge will not be nearly as bad as Isabel considering the track of the storm will be north and east of the area.

The winds however, will rival those of Isabel, and many places along the interstate 95 corridor will receive winds that exceed of Isabel. The highest wind gusts registered at the local airports across the Maryland area averaged the 50-65 mile per hour range. However, as you see on our map below, the highest wind gusts for the area could exceed hurricane force, with some isolated gusts touching 80mph. The reason for this is because of the extreme winds residing just above the surface Monday and Tuesday. This coupled with heavy rains and advecting cold air from the northwest could bring some of these extreme winds to the surface, producing the aforementioned winds. In addition, the rainfall in both Irene and Isabel is not to be compared with Sandy as the storm will have much slower movement, producing rainfall totals over 8'' in the Baltimore metropolitan areas with parts of the Delmarva up into New Jersey receiving over 10 inches and up to one foot of rainfall.

This will promote freshwater flooding in the areas that are not east of the storm, making for a dangerous scene nonetheless. For those that are in the way of the storm though on the eastern side, the surge that could rival the Long Island Express of 1938 thanks to slow movement and the piling of the water will be corresponding with the full moon, maximizing the astronomical tides on top of the storm surge. The storm surge in Long Island sound coudl be equatable almost to a category two hurricane on the scale. Regardless, New York city needs to take precautions on the subway to make sure they do not get flooded out admist torrential downpours. This even applies to rural areas with leaves clogging the storm drains as the trees are shedding their leaves this time of year. The places most at risk for this lie further to the south where the foliage is near peak season, such as Baltimore and Washington DC. Many areas have many trees falling from the trees, and many leaves additionally leading to stoppages and flooding via clogged drainages. One must keep in mind a combination of the very heavy and consistent rainfall from this storm coupled with the winds in a system like this spread hundreds of miles from the center, with the strongest winds as of this point looking to be just north of the center as well as to the southwest of the center. The storm will have a very large windfield overall, and that is to blame for the extraordinary duration of the tropical storm conditions likely to be faced in the megalopolis. There will likely be winds gusting over 40-50mph all the way from DC to Boston all at the same time.

The threat of snowfall however, is still not to be forgotten, and the threat should continue to exist for snowfall heading into the early and middle week. The only place that is really likely to see snow for the time being is West Virginia in the Appalachian Mountains including Snowshoe ski resort where the total snowfall could range from 10 to 15 inches overall. Some isolated areas could even see 2 feet or snow or more. This brings me to my next question, should any of the big cities expect snow on the back side? In many instances, people would expect a storm like this to produce snow on the back end, however in this instance there is simply not enough cold air to do it in this case, though more recent runs have taken temperatures for Baltimore down into the mid 30's with the chance of a few flakes mixing in towards places north of Frederick and a bit of snow into the mountains near Emmittsburg, Maryland. Stay tuned for the latest complete details as the storm approaches.

www.hwpcwx.org

[Jmister]

Nice writeup, Zak.

Looks like the 00z GFS is an entirely new endgame. It comes into the coast much quicker and turns west more gradually. This means central PA stays on the south side of the Low. Cold air is able to infiltrate from the west (even SW) and possibly change some areas to snow Tuesday afternoon.

[PottercountyWXobserver]

**HEADLINE** hehe

"Sandy gives extreme blow job to Southern NewEnglanders."

[MAG5035]

Nice writeup, Zak.

Looks like the 00z GFS is an entirely new endgame. It comes into the coast much quicker and turns west more gradually. This means central PA stays on the south side of the Low. Cold air is able to infiltrate from the west (even SW) and possibly change some areas to snow Tuesday afternoon.

Oh wow, yea it does. Turns like the central third to snow by 90. I mean its def possible if the low goes far enough to the north to allow the cold conveyor belt to not bypass us south and yet be close enough to keep us in the heavier precip. I still think that the low takes this more "progressive" track rather than make such a severe turn that it goes right over our head or not even make it this far inland before it starts filling in. Still though.. at this point if I were the weather channel live guy reporting in the storm I would want to be in like Elkins, WV.

By the way, gonna be up in State College for the game tomorrow, you goin?

[NortheastPAWx]

Man, I got so many people I'm worried for in this storm - my parents in W-B and RDG respectively, a close friend and my oldest sis in NYC, and ofc all of us here in C PA...it's going to be a long weekend.

[EasternUSWX]

Rain starts Sunday, ends maybe Friday lol. Cut offs for the win.

[lakeeffectkid383]

Sandy means business

Hello all, Sandy continues to move northward tonight with winds just above hurricane force at 75mph, with higher gusts. Overall, the storm is exhibiting characteristics much like those of an extratropical cyclone, and as labeled by the National Hurricane Center earlier today, the transition is already under way. The storm, which was previously moving northward at quite a fast pace through the southern and further north into the central Bahamas has slowed significantly, and came almost to a temporary stall off the coast of Florida. The winds, which as stated are at 75mph now, should continue to press northward at a slower pace, 7-12mph. The storm looks the way it does now because of wind shear that is displacing the center of circulation from the convection, though this situation is something not uncharacteristic for storms like Sandy, especially those transitioning into a hybrid or extratropical cyclone. The storm should continue on that northerly heading as described for the next few days, with a jog to the east occurring Sunday. Though the storm will be off Cape Hatteras by that time, clouds associated with the storm, and even showers will begin impacting the area on Sunday morning with the best chances for rain coming to southeast areas Sunday evening. Sunday will be the least impact many see from Sandy, with Monday and Tuesday beng the days where the brunt of the effects are felt. Many are worried and are bringing up situations like Isabel or Irene in terms of impact. In relation to those storms, there are ways to compare Sandy or its hybrid low that could surprise certain people. For those in places west of the Chesapeake Bay in Maryland, the storm surge will not be nearly as bad as Isabel considering the track of the storm will be north and east of the area.

The winds however, will rival those of Isabel, and many places along the interstate 95 corridor will receive winds that exceed of Isabel. The highest wind gusts registered at the local airports across the Maryland area averaged the 50-65 mile per hour range. However, as you see on our map below, the highest wind gusts for the area could exceed hurricane force, with some isolated gusts touching 80mph. The reason for this is because of the extreme winds residing just above the surface Monday and Tuesday. This coupled with heavy rains and advecting cold air from the northwest could bring some of these extreme winds to the surface, producing the aforementioned winds. In addition, the rainfall in both Irene and Isabel is not to be compared with Sandy as the storm will have much slower movement, producing rainfall totals over 8'' in the Baltimore metropolitan areas with parts of the Delmarva up into New Jersey receiving over 10 inches and up to one foot of rainfall.

This will promote freshwater flooding in the areas that are not east of the storm, making for a dangerous scene nonetheless. For those that are in the way of the storm though on the eastern side, the surge that could rival the Long Island Express of 1938 thanks to slow movement and the piling of the water will be corresponding with the full moon, maximizing the astronomical tides on top of the storm surge. The storm surge in Long Island sound coudl be equatable almost to a category two hurricane on the scale. Regardless, New York city needs to take precautions on the subway to make sure they do not get flooded out admist torrential downpours. This even applies to rural areas with leaves clogging the storm drains as the trees are shedding their leaves this time of year. The places most at risk for this lie further to the south where the foliage is near peak season, such as Baltimore and Washington DC. Many areas have many trees falling from the trees, and many leaves additionally leading to stoppages and flooding via clogged drainages. One must keep in mind a combination of the very heavy and consistent rainfall from this storm coupled with the winds in a system like this spread hundreds of miles from the center, with the strongest winds as of this point looking to be just north of the center as well as to the southwest of the center. The storm will have a very large windfield overall, and that is to blame for the extraordinary duration of the tropical storm conditions likely to be faced in the megalopolis. There will likely be winds gusting over 40-50mph all the way from DC to Boston all at the same time.

The threat of snowfall however, is still not to be forgotten, and the threat should continue to exist for snowfall heading into the early and middle week. The only place that is really likely to see snow for the time being is West Virginia in the Appalachian Mountains including Snowshoe ski resort where the total snowfall could range from 10 to 15 inches overall. Some isolated areas could even see 2 feet or snow or more. This brings me to my next question, should any of the big cities expect snow on the back side? In many instances, people would expect a storm like this to produce snow on the back end, however in this instance there is simply not enough cold air to do it in this case, though more recent runs have taken temperatures for Baltimore down into the mid 30's with the chance of a few flakes mixing in towards places north of Frederick and a bit of snow into the mountains near Emmittsburg, Maryland. Stay tuned for the latest complete details as the storm approaches.

www.hwpcwx.org

what do you use for your graphics? Love them.

[EasternUSWX]

what do you use for your graphics? Love them.

Photoshop.

And thank you

[djr5001]

0z Euro continues to be furthest south solution... targeting delmarva again

[EasternUSWX]

0z Euro continues to be furthest south solution... targeting delmarva again

I heard it hits basically Cape May.

[djr5001]

I heard it hits basically Cape May.

looks a hair south of Cape May to me... Cape May on northern edge of what center of circulation would be

[EasternUSWX]

looks a hair south of Cape May to me... Cape May on northern edge of what center of circulation would be

Either way we are fooked.

[djr5001]

Either way we are fooked.

it pretty much moves west to around baltimore then just sits there for 24-36 hours... that will really do some damage

From what I have seen all week... to me this still seems like the furthest possible south solution... I think GFS is close to furthest north

Some people keep saying it will be closer to NYC because some models like the GFS have trended there and seem to be ignoring the fact that the Euro has been locked on and barely drifted over the past few days worth of runs!

This set up is too crazy to rule anything out (even snow to the west/parts of central pa) until we see the shortwave begin to interact with Sandy

[NortheastPAWx]

ECM has widespread 60+ knot winds at 850mb 0z 10/30.

[EasternUSWX]

This is nuts.

[MAG5035]

it pretty much moves west to around baltimore then just sits there for 24-36 hours... that will really do some damage

From what I have seen all week... to me this still seems like the furthest possible south solution... I think GFS is close to furthest north

Some people keep saying it will be closer to NYC because some models like the GFS have trended there and seem to be ignoring the fact that the Euro has been locked on and barely drifted over the past few days worth of runs!

This set up is too crazy to rule anything out (even snow to the west/parts of central pa) until we see the shortwave begin to interact with Sandy

Yea the models (sans the euro) have had their moments here and there this week with letting Sandy escape but overall.. I've been amazed at the consistency of such intense and destructive solutions being put out by everything, including less skilled models like the NOGAPs run after run. The strength as well.. i mean the 0z GFS ensemble MEAN is incredibly in the 960s, operationals have been cranking out pressures much lower than that all week. I really was thinking earlier in the week some of the models were over-deepening the system a fair amount and i still do to a degree but now I acknowledge that this could hit record low pressures (perhaps down into 950s). The model consistency with this is reminiscent of the consistency apparently displayed from 4-5 days out leading up to the 93' Superstorm. I don't know personally (the '93 storm happened on my 7th b-day) but that's one thing I've always read is that all the major models were pegging that one days in advance at a time when computer forecasting was at a much more basic stage. We shall see if we ultimately end up with a storm that has the ferocity that the computer models have been portraying all week.

[EasternUSWX]

First watch out

Flood Watch

FLOOD WATCH

NATIONAL WEATHER SERVICE STATE COLLEGE PA

439 AM EDT SAT OCT 27 2012

...HEAVY RAIN FROM SANDY WILL BRING THE THREAT FOR FLOODING EARLY

IN THE UPCOMING WEEK...

.AN EXPANSIVE PLUME OF TROPICAL AND ATLANTIC MOISTURE ASSOCIATED

WITH SANDY WILL SURGE INTO THE AREA FROM THE SOUTHEAST LATE

SUNDAY NIGHT THROUGH TUESDAY...BRINGING HEAVY RAIN TO THE REGION.

THE HEAVY RAINFALL COULD LEAD TO WIDESPREAD FLOODING ACROSS THE

LOWER SUSQUEHANNA VALLEY AND ADJACENT PARTS OF THE STATE.

PAZ056>059-063>066-280845-

/O.NEW.KCTP.FA.A.0001.121029T0600Z-121031T0000Z/

/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER-

439 AM EDT SAT OCT 27 2012

...FLOOD WATCH IN EFFECT FROM LATE SUNDAY NIGHT THROUGH TUESDAY

EVENING...

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A

* FLOOD WATCH FOR A PORTION OF CENTRAL PENNSYLVANIA...INCLUDING

THE FOLLOWING AREAS...ADAMS...CUMBERLAND...DAUPHIN...

LANCASTER...LEBANON...PERRY...SCHUYLKILL AND YORK.

* FROM LATE SUNDAY NIGHT THROUGH TUESDAY EVENING.

* LOCALLY EXCESSIVE RAINFALL OVER 4 INCHES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING ON SMALL

STREAMS...CREEKS...POOR DRAINAGE...URBAN AND LOW-LYING AREAS

BASED ON CURRENT FORECASTS.

YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE

FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE

PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

[vr4jon]

Great info guys. Never post much here but learning a lot and really looks like we are in for the storm of a lifetime. Keep safe everyone!

[pawatch]

looks a hair south of Cape May to me... Cape May on northern edge of what center of circulation would be

Looks like Cape May is going to get about 8" of rain. Wow that would be major flooding for them.

I haven't heard much on how much storm surge they are expecting in them area's.

From just looking at the models I'm thinking about 4" of rain for myself and 30mph sustained winds.

Looking at the maps I posted is the low only going to get in the 970's?

[EasternUSWX]

-- Changed Discussion --

LATEST 00Z-06Z MODEL GUIDANCE CONTINUES TO TIGHTEN UP THE RANGE OF POSSIBLE LANDFALL LOCATIONS...WITH THE MEAN NOW BEING BETWEEN ATLANTIC CITY NEW JERSEY...AND OCEAN CITY MARYLAND MONDAY EVENING. THIS PATH IS VERY OMINOUS FOR THE LARGE POPULATION AREA OF SOUTHEASTERN PA AND THE LOWER SUSQ VALLEY...WITH BANDS SQUALLS CONTAINING EXCESSIVE RAINFALL AND STRONG DAMAGING WIND GUSTS IMPACTING THE REGION. TO COMPLICATE MATTERS...THERE WILL ALSO LIKELY BE A SEVERE WEATHER/TORNADO THREAT NEAR...AND TO THE NORTH OF THE KLNS AND KMDT AREAS LATER MONDAY NIGHT. WIND FIELDS SURROUNDING THE LOW CENTER WILL BE VERY IMPRESSIVE MONDAY INTO TUESDAY AS SANDY TAKES A LIKELY TRACK WWD INTO CENTRAL OR SOUTHERN PENN. NORTHEAST TO NW WINDS OF 60 PLUS KTS ARE FCST TO BE ONLY ABOUT 2 KFT AGL...WITH THE 50 KT CONTOUR AT 1 KFT AGL. THESE WINDS WILL EASILY BE MIXED DOWN TO THE SFC BY THE HEAVY RAINBANDS...BUT LIKELY MOST SEVERELY IMPACT THE HIGHER TERRAIN OF THE SOUTH AND EAST...BEFORE BECOMING SLIGHTLY DAMPENED TWD THE CENTRAL MTNS. HEAVIER QUASI-SPIRAL RAIN BANDS WILL EASILY MIX OUT OCNL GUSTS AROUND 50KTS SHOULD THIS EXPECTED MODEL MEAN TRACK /AND TPCS/ VERIFY. WE POSTED A FLOOD WATCH FOR THE SE ZONES A SHORT TIME AGO...AND IT WILL RUN FROM 06Z MONDAY THROUGH 00Z WED...WITH 4 INCHES OF MORE LOOKING LIKE A GOOD POTENTIAL. LOCALIZED MUCH HEAVIER AMOUNTS OF 6-10 INCHES ARE ALSO WITHIN THE REALM OF POSSIBILITIES AS THE HYBRID STORM IN CAPTURED...THEN ABSORBED BY THE AMPLIFYING AND STRONGLY NEG TILT UPPER TROUGH. IN ADDITION TO THE PLETHORA OF PROBLEMS RELATED TO WIND...RAIN AND POTENTIAL SEVERE CONVECTION...THE POTENTIAL FOR SEVERAL INCHES OF HEAVY WET SNOW STILL REMAINS FOR THE RIDGES OF THE LAUREL HIGHLANDS BEGINNING LATE MONDAY OR MONDAY NIGHT...AND CONTINUING THROUGH TUESDAY AS THE 850 MB WET BULB TEMPS COOL TO JUST UNDER 0C FROM THE SOUTHWEST. MUCH HEAVIER SNOW IS EXPECTED FURTHER SOUTH ACROSS THE MTNS OF WVA. SANDY AND THE UPPER TROUGH CAPTURING IT FROM THE WEST...EVOLVE INTO A LARGE/STACKED LOW ACROSS THE NRN VIRGINIAS OR CENTRAL PENN TUESDAY BEFORE GRADUALLY FILLING AND DRIFTING NNE DURING THE MIDWEEK. SCATTERED TO NUMEROUS RAIN SHOWERS...MIXED WITH SOME WET SNOW ACROSS THE RIDGES WILL FOLLOW FOR THE MID-WEEK/HALLOWEEN PERIOD.

[Jns2183]

After reading CTP discussion and looking at the updated model tracks, I think we are in for a ride. I still feel there will be some wind guests on the sw side that will rival those on the NE side due the position of LLJ jet. One of the red taggers in the New England forum mentioned that in hybrid storms over the ocean there are usually some phenomenal wind guest in the area located at an angle of 190-210 degrees from the center. Also very worried about the mass amount of leaves in the street leading to clocked drains.

[Voyager]

It seems, fortunate for us, that my area (Schuylkill County) resides on the "drier" north side of the storm center as most products show about a 3-4 inch maximum in my area for the event.

[mahantango#1]

It seems, fortunate for us, that my area (Schuylkill County) resides on the "drier" north side of the storm center as most products show about a 3-4 inch maximum in my area for the event.

it could change!

[Jns2183]

I live in Cumberland county and it will be close. The new NHC guidance takes the center through Reading moving NW. The direction of movement will be interesting in whether it is moving NW, WNW, or W when it gets to C PA.

[Voyager]

it could change!

Yes, I know it can. That was "here is the current thinking" kind of post.

[NeffsvilleWx]

Yea the models (sans the euro) have had their moments here and there this week with letting Sandy escape but overall.. I've been amazed at the consistency of such intense and destructive solutions being put out by everything, including less skilled models like the NOGAPs run after run. The strength as well.. i mean the 0z GFS ensemble MEAN is incredibly in the 960s, operationals have been cranking out pressures much lower than that all week. I really was thinking earlier in the week some of the models were over-deepening the system a fair amount and i still do to a degree but now I acknowledge that this could hit record low pressures (perhaps down into 950s). The model consistency with this is reminiscent of the consistency apparently displayed from 4-5 days out leading up to the 93' Superstorm. I don't know personally (the '93 storm happened on my 7th b-day) but that's one thing I've always read is that all the major models were pegging that one days in advance at a time when computer forecasting was at a much more basic stage. We shall see if we ultimately end up with a storm that has the ferocity that the computer models have been portraying all week.

I turned 8 during that storm. I got super mario kart as a gift and was incredibly disappointed because we lost power.

[EasternUSWX]

Here is our forecast for today along with the factors on the plate for Sandy.

http://www.hwpcwx.org/2012/10/preparation-day-sandy-on-way.html

[Aratonolme]

Thank you gentlemen for the great information. The last time I was really concerned about a storm was in March of 93 with the snow-hurricane.

[Santa Clause]

Well guys how does GFS look? To me it looks really intense and gets a lot of us northeast of the center....however I am terrible at interpreting maps lol.