From Tony Wolf:
I’ll continue to pass along weekly (more or less) regional weather forecasts that might be of interest to grape producers and others. The forecasts go into somewhat more detail than most other weather forecasting services, and will typically reach out 7 to 10 days, and in some cases further.
With the exception of SW Virginia, the spring thus far has been generally benign with respect to frosts. There were some vineyards that dropped below freezing in the southwest on the mornings of 12 and 13 April, as early morning winds subsided and there was little or no cloud cover to retain heat. Parts of North Carolina and northern Georgia also took pretty big hits, as did some areas in the mid-west US.
Conditions throughout the mid-Atlantic now are obviously dry, with northern Virginia localities running 5- to 6-inch rainfall deficits for the year thus far. Rains forecast for the coming weekend and into next week may alleviate immediate concerns, but the long-term (summer) forecast (http://www.cpc.ncep.noaa.gov/products/predictions/90day/) is projecting above-average temperature and below-average precipitation for mid-Atlantic regions, a pattern driven in part by the lack of a strongly developed El Nino Southern Oscillation pattern (ENSO). We have expanded our irrigation capacity with here at the Ag Research and Extension Center and would encourage grape producers who have chronic problems with drought conditions to consider taking similar measures. Drought can delay crop ripening and impair crop/wine quality (see Chapter 9 in the Wine Grape Production Guide).
David’s weekly forecast follows… sounds like an interesting weekend coming up..
TKW
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WxRisk.com – Windsong Forecasts
This morning statement is being issued at 1700 EDT APRIL 16
*** if you are unfamiliar with WXRISK.COM *** Click HERE to learn more about it ****
There is increasing potential for a significant or major severe weather outbreak for much of the southeast and lower Middle Atlantic states this coming weekend (21-22 April). (GA, SC, NC, VA, MD, eastern TN and WVA)
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So far this SPRING 2012 we have been pretty lucky on the East Coast but does not look like that Luck is going to last. Starting at the end of this week the jet stream over the eastern portion of North America is going to undergo a major amplification. A deep trough in the jet stream is going to form over the eastern Pacific Ocean on Thursday and Friday. This in turn… will force a large bulge or ridge to form over the West Coast and the Rockies… and this in turn will force large deep trough to form over the East coast this coming weekend.
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At the surface this will appear as the cold front which will move through the Midwest on Friday and head towards East Coast. However because of this deep trough that will building over the East Coast the cold front will come to a screeching halt along the East Coast running on a line from Atlanta to Albany NY.
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Low pressure is going to form over AL and GA on Saturday and track up the Appalachian Mts along the stalled cold front and head into eastern PA eastern NY State and New England by Monday. In some ways this Low track will be similar to what we might see during the wintertime with regard to East Coast winter storm. But there are some important differences.
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FIRST… ahead of this cold front is going to turn very warm again up and down the East Coast.
SECOND… HIGH pressure off the East Coast will be sending in strong southerly winds which will increase the low level moisture from SC to Maine ahead of the cold front.
THIRD.. The pattern that sets up in the jet stream at the upper levels of the atmosphere will become very ominous looking for the East Coast and especially for GA to MD. The Jetstream over the East Coast will take on a particular tilt or alignment in the atmosphere which meteorologists call a negative tilt — this is when the trough axis is aligned in a NW to SE direction.
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Thus when the surface area of LOW pressure forms over GA on Saturday it will rapidly intensify as it tracks over Raliegh and central NC and into central VA/ metro Richmond area on Sunday. Because of the temperature contrast west of the front vs. east of the front… the low level southeasterly winds… the upper level south winds that will become Easterly as the Low tracks through NC and VA the potential exists for significant severe weather outbreak from Georgia into New England.
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These two LINKS can show you the threat nicely
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12Z MONDAY AFTERNOON EUROPEAN MODEL valid 4/22
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12Z MONDAY AFTERNOON EURO MODEL valid 4/23
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The thunderstorms will not only be significant rain producers but the potential exists for chromatic thunderstorms as well as large HAIL. Over the next two days I will be issuing statements on this as we get closer and closer to the event. Most areas up and down the East Coast will see anywhere from 1 to 5 inches of rain BUT … over the mountains blue ridge and the Shenandoah Valley as well as Western NC western MD and central and northeastern PA rainfall amounts could be significantly higher.
*Here is the approximate sequence of events for this weekend starting on Friday.
FRIDAY 4/20. Everybody looks fine. The cold front will be sweeping through the delta and the Ohio Valley. There will be increasing showers and thunderstorms developing Friday night into Saturday morning over AL, GA, eastern TN.
SATURDAY 4/21 storms/ rain over GA SC, eastern TN and western NC but it will stay dry and even sunny over eastern half NC most for VA, MD, DE, eastern PA.
SAT NIGHT: Heavy storms /rains move north in western VA by 8pm into western MD, central PA… and into all of eastern NC, VA, central MD by 2am Sunday and into MD, eastern PA and NJ as well as NYC
SUNDAY morning the Upper and surface Low travel right over Raleigh and through central VA / Richmond. SEVERE WX THREAT could be HIGH for all of northern half NC – VA-MD with heavy rain. More heavy rains all for central and eastern PA NJ DE eastern NY Moderate rains into New England … by 2pm LOW is right over Richmond VA… not good
SUNDAY 7PM… the surface LOW begins to Weaken as it moves into eastern MD and towards Philly … worst is over for NC MD VA ..still some rain over nw VA and western MD and western PA… heavy rains in the NE;
MONDAY 7AM Low is over Philly Squall line of severe storms driving thru NJ, NYC se NY, Long island into CT
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David Tolleris … ” DT”
wxrisk@comcast.net
804 307 8070
ask for DT