The Northeast Weather Blog...
Increasing chances for rain over the next seven days...
Posted by: Zachary Labe, 19:27 GMT 6. Květen 2013 +1
Zachary Labe
6 May 2013
Weekly Forecast - May 6-13

As the dry and seasonal weather begins to break across the Northeast, increasing threats for rain are likely over the area. A widespread soaking rain is likely for the middle to end of the week followed by significantly below normal temperatures to start off the second week in May.

"Afternoon Thoughts" (Updated 5/6)
As the physical and social aftermath from Hurricane Sandy continues to unfold, operations in the National Hurricane Center (NHC) and National Weather Service (NWS) are focusing on new ideas for warning the general public in advance and during tropical systems. The previous system included warnings being issued by both meteorological bureaus therefore often confusing the general public in terms of emergency management warnings and advisories. While set criteria and definitions exist for advisories/warnings, the general public cannot differentiate differences such as between a Hurricane Warning and an Inland Hurricane Force Wind Warning. Therefore a new system is necessary to continue NOAA's goals of providing outreach and warning to the general public.

New proposals include continuing tropical storm/hurricane warnings inland if the threat of hazard to public property and life continues despite the storm system losing tropical characteristics or perhaps not fitting the exact advisory criteria. Also the agency responsible for issuing the advisories, will remain responsible for the life of the storm. This was a critical error during Sandy where hurricane warnings by the NHC were placed next to benign wind advisories by the NWS. Confusion occurred both through broadcast meteorology outlets and through other private sector companies.

A large problem exists. This problem continues to question where the line between science and weather awareness exists. Is it more important to recognize the exact science of a threatening storm system or should meteorological agencies focus on warning the public of impending weather hazards? I think it is a matter of a continued simplification of the NWS hazards and warnings network where well over 50+ types of advisories exist. For instance, the difference between a freezing rain advisory and winter weather advisory at times is just subject to forecaster opinion let alone the public's understanding of the differences. As a scientific community we need to expand and simplify our communication effort. This is where our current greatest challenges exist to continue to increase awareness and warning times. And in times of extreme and severe weather, the less conflicting data the better. Unfortunately, it seems the field is heading in the opposite direction as the number private weather companies doubles and the industry continues to polarize.

For further reading...

Don't Be Such a Scientist by Randy Olson- Excellent book detailing the challenges of communication in the sciences

Link- Article release from the Huffingtonpost detailing updates to the warning system post Sandy

Link- NHC post-Sandy case study and storm evaluation (157 pages)

"Regional Radar"

(Courtesy of NOAA)

"Regional Satellite"

(Courtesy of Penn State Meteo.)

"Regional Advisories"

(Courtesy of NOAA)

"Weekly Forecast" (Updated 5/6)
Monday- High pressure remains in control across the Northeast. PWATs aloft remain nearly 3SD below normal at only a few tenths of an inch. Therefore, clear skies will dominate the region. Despite it only being early May, the sun angle is equivalent to that of the middle of August. In some cases, given the lower water vapor content this time of year, the sun's rays may actually be stronger than during the summer months. Today is an example of this where the UV index reaches nearly 10 over the East Coast. Given ideal radiational cooling conditions, diurnal temperature swings will be nearly 30-40F. Highs will be uniform for most areas ranging from the lower to upper 70s with temperatures falling into the 40s overnight Monday.

Tuesday- As a result of increasing moisture aloft, clouds will be increasing from southeast to northwest during the day. A cutoff surface low nestled across the southeast will begin to shift slowly northward along the east coast. An easterly flow will begin with a marine air mass pushing inland throughout the day. Therefore, high temperatures will peak higher across western areas such as Pennsylvania and New York where there will be a lower marine influence. Temperatures will round out in the upper 70s in these areas with numbers in the upper 60s farther east. A few rain showers are possible across Maryland, Pennsylvania, New Jersey, and Delaware during the day. HIRES 4km NMM total QPF remains at or below 0.1in for most areas, so a widespread rain is next expected. Continued dreary conditions will occur overnight Tuesday with lows generally in the 50s for most station.

Wednesday- Current ECMWF/GFS guidance indicates a surge of higher moisture plumes in a tight area of frontogenic forcing along a boundary north of the surface low. This will place the highest threat of rain across most of New Jersey west into Pennsylvania. High resolution guidance indicates total QPF ranging from 0.5-0.75" favoring eastern orographically enhanced areas such as the Blue Ridge Mountains and South Mountain in Pennsylvania. Up to 1" of QPF cannot be ruled out. Rain will fall steady throughout much of the day. To the north and south of this moisture axis, generally scattered light rain or drizzle showers can be expected under the influence of overcast skies. Temperatures will struggle to reach 70F for most areas.

Thursday- A cold pocket of air across the region in association with a shortwave rotating through will enhance diurnally-favored convection. The easterly flow will relax a bit during the day favoring some partly cloudy skies. Mild surface instability and low freezing levels may enhance a few convective tops with the threat of small hail. See severe weather outlook discussion below. Given the localized nature of the precipitation, QPF will will range from less than a tenth of an inch to up to 0.5 inches. The general blocking nature of the synoptic pattern will enhance the threat of heavy rain for any showers that form. By evening, lowering daytime surface instability will end most rain shower development.

Friday-Sunday- Daily highs in the mid 60s to lower 70s can be expected with the threat of occasional rain showers due to the close proximity of the cutoff low. Closer to the coast, cooler temperatures and low stratus can be expected in response to the marine layer. Total MREF QPF totals remain light each day and localized with amounts below .1" generally for each 12 hour period.

Monday- A deep upper level trough will sink south across the Northeast with H85s falling below -5C as far south as I-80. Well below normal temperatures can be expected in addition to a northwest flow. A few rain showers are also possible given the cold flow instability.

"Current Surface Map and Weekly History of Jet Stream Position"

(Courtesy of Weather Underground)

"Severe Weather Outlook" (Updated 5/6)
A cutoff low moving up Atlantic coast from the southeastern states will allow an onshore, easterly flow to dominate the weather for a majority of the upcoming period. Low stratus and cooler temperatures from the marine layer will inhibit surface instability. Thursday will feature a smaller cold pocket move over the area in association with an embedded shortwave near the upper level low. This will temporarily break the maritime flow and allow some sunshine across Northeast especially for areas 50mi+ inland. Current medium-range model guidance indicate increasing lapse rates and mild SBCAPE approaching 100-200 j/kg. Freezing levels will fall to below 10,000ft. Therefore, the threat for some small pea or nickel-sized hail is possible with convection that may form during the Thursday. In addition, PWATs will be rising to near 1.5" increasing the threat for heavy rain from any thunderstorms that form. Movement will be slow given the blocking-favored pattern. The threat for any convection will be highest across areas from northern Pennsylvania to southern New England, where they will be closer to the cold pocket of air. In general the severe weather threat remains low.

Long term wavelengths suggest increasing threats of severe weather towards the end of the month as the thermal boundary shifts north to southern Canada and will occasional dip down across the northern contiguous United States.

"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Wildfire Outlook and Drought Watch" (Updated 5/6)
The highest threat for forest fire development over the next seven days is likely during the May 6-7 time frame with high pressure dominate over the region and PWATs sub 0.25 inches. This indicates very dry air over the area with dew points in the 30s as far south as I-80. Soil moisture anomalies remain at 1-2SD below normal across upstate New York and parts of New England. On the other hand boundary layer winds remain generally light and below wildfire criteria for development. Also a slight easterly flow at the surface will allow PWATs to increase over the next 24 hours lowering fuel levels. As moisture increases over the Northeast by day 3, any threat of forest fire development will diminish.

Despite below normal soil moisture anomalies and precipitation deficits at nearly 6" below average, the threat for long term drought conditions remains low given the upcoming active weather regime. Several chances of rainfall are likely over the seven day period, and long term prognostics indicate a continued active jet stream through the end of the month.

Here is a link to the criteria for fire development... Link.

Criteria for rapid initiation and spread of wildfires:

1. Winds must be sustained at 15 mph (13 knots) for two hours or more, and

2. Minimum Relative Humidities (which usually occur in the afternoon) must be 30 percent or less, and

3. 10-hour Fuel Moistures must be 15 percent or less (and expected to remain there for two or more days).

"Fire Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Gardening Outlook" (Updated 5/6)
It has been an excellent start to the gardening season for many areas throughout the Middle Atlantic. Seasonable temperatures without the threat of frosts and freezes have helped most agricultural communities get a normal start to the growing season. Soil moisture anomalies over the Northeast range from below normal from New York to Vermont to Maine and near normal from Pennsylvania to Maryland. However, the latest QPF output from the Weather Prediction Center indicates a widespread 1.00-1.75" of rain over the entire Northeast through the next seven days. While their QPF prognostics tend to run a bit high, it is likely many areas will see a general half inch to inch of rain during the next week with several chances of precipitation in correspondence with an onshore flow.

The first rain event on Wednesday and Thursday will favor the PA/MD/NY/DE region with a soaking, stratiform QPF event expected. Totals around 0.5in are likely. The easterly flow will continue through next Monday with chances of rain showers and/or convection possible each day across the East Coast. However, given the convective nature of the QPF, not all areas will see rainfall during the period. Nevertheless, it is expected to bring a beneficial rain event to areas that are nearly 5-10" below normal of annual precipitation. No hydrometeorological concerns are likely over the seven day period.

There may be a threat for frost/freeze concerns across New England in the May 13-14 time frame as H85s drop below -5C to areas as far south as northern Pennsylvania. This will be something to monitor for those areas that have already started their growing season. But temperatures will begin to warm up to above normal values by midweek.

"Soil Moisture Anomalies and 5-day Precipitation Amounts from the Weather Prediction Center"

(Courtesy of NOAA)

"Monthly Outlook" (May)
MJO wave amplitude will continue to increase over the next few days in addition to a ridge building across the northern Pacific. This will continue a the stretch of -NAO teleconnection pattern over the next two weeks with near normal to below normal temperatures across the Northeast. Current MREF guidance suggest a cold pool of air moving south out of Canada for the second week of May with H85s dropping sub 0C as far south as North Carolina. This air accompanied by a high pressure may allow some radiational cooling-favored areas to drop below freezing during this period. This time will favor May 13-15th with the highest threat across the sheltered valleys of New England. By the end of the second week of May temperatures will begin to rise as the upper level trough shifts northeast and upper level heights begin to rise. The -NAO pattern will begin to break in this time frame allowing for a mild end of the weather. While wavelengths presently do not favor any significant heat waves across the East Coast, a few well above normal temperatures can be expected before the month's close. Temperatures on a whole for the month of May will average near normal for most climatological reporting sites.

In addition, the pattern will favor a higher than normal threat of severe weather across the northeast due to the close extreme temperature gradient between the warmer air over the area and a waning polar air mass across southern Canada. It is likely the first widespread severe weather outbreak of the spring season occurs over the Northeast before the close of the month. Current soil wetness anomalies over the Northeast indicate significantly dry weather over the area for the past six weeks, particularly across New England. As jet stream wavelengths shorten with the expected pattern break during the first week in May, increasing threats for rainfall are likely. Given the convective nature of these rain threats, precipitation will likely fall slightly below normal for most climatological reporting stations. The driest period of May will fall during the first seven days with increasing chances thereafter.

"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"

(Courtesy of NOAA)

Lower Susquehanna Valley Doppler...

(Courtesy of WGAL)

Follow my 24hr forecasts on Twitter... Link and Facebook... Link.

"Linglestown, PA 2013 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 1
Severe Thunderstorm Warnings- 2
Tornado Watches- 1
Tornado Warnings- 0
Total Thunderstorms- 5

(Precipitation Stats...)
Flood Watches- 0
Flood Warnings- 0
Flash Flood Watch- 1
Flash Flood Warnings- 0
January precipitation- 3.17"
February precipitation- 1.90"
March precipitation- 1.73"
April precipitation- 2.67"
May precipitation- 2.11"
Yearly precipitation- 11.58"

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Watch- 0
Excessive Heat Warnings- 0
90F days- 0
100F days- 0
Highest Temperature- 86F
Categories:Weekly Forecast
Updated: 13:50 GMT 20. Květen 2013   Permalink | A A A
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Increasing rain chances over the next two weeks...
Posted by: Zachary Labe, 14:34 GMT 5. Květen 2013 +0
"Current Temperature"


"Current Dewpoint"


"Current Surface Map and Weekly History of Jet Stream Position"


"Regional Radar"


"Regional Satellite"


"Regional Advisories"


"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"


"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"


"12hr ...
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Flaws in the Present Meteorological Community Infrastructure
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Zachary Labe
25 March 2013
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Nearly a month after the end of the official meteorological winter, folks across the Middle Atlantic are presently cleaning up from a late...
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March 25 Northeast Winter Storm...
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"Current Northeast Surface Station Plots"


"Current Surface Map and Weekly History of Jet Stream Position"


"Regional Radar"


"Regional Satellite"


"Regional Advisories"


"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"


"Seven Day Departure from Normal Precipitation"


"Forecast Max Temperatures"


"Fo...
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"Current Northeast Surface Station Plots"


"Current Surface Map and Weekly History of Jet Stream Position"


"Regional Radar"


"Regional Satellite"


"Regional Advisories"


"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"


"Seven Day Departure from Normal Precipitation"


"Forecast Max Temperatures"


"Fo...
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Updated: 01:04 GMT 19. Březen 2013   Permalink | A A A
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Cornell University- Atmospheric Sciences Student; Central PA SKYWARN Storm Spotter; American Meteorological Society Member; PA CoCoRaHS Branch Member

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