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Happy Meteorological Fall

September 1, 2014
Fall_Foliage_Peak

Average Time of Peak Fall Foliage in the Washington Region

Summer Pattern Setting Up through Mid Week

August 30, 2014

Summer has almost been absent this year but things are about to change as we head back to school and work on Tuesday.  An upper level ridge will build across the southeast pumping heat and humidity into the Mid-Atlantic and New England. Temperatures on Tuesday may soar into the lower to middle 90s.  Saturday through Labor Day looks typical around Washington with partly cloudy skies, highs in the middle to upper 80s and scattered afternoon showers and thunderstorms.

Temperture anomalies (image courtesy tropicaltidbits.com)

Temperature anomalies August 30th through September 4th (image courtesy tropicaltidbits.com)

Upper Level (500 mb) height anomalies (image courtesy tropicaltidbits.com)

Upper Level height anomalies August 30th through September 4th (image courtesy tropicaltidbits.com)

Tropical System May Threaten East Coast Next Week

August 22, 2014
Image Courtesy: tropicaltidbits.com

Image Courtesy: tropicaltidbits.com

The tropics are beginning to heat up.   A tropical system may develop north of the Dominican Republic this weekend then threaten the United States East Coast as we head into the upcoming work week.

A cold front approaching the Mid-Atlantic from the west during the middle to later part of next week and an area of high pressure offshore may direct this system up along the east coast or just off the Mid-Atlantic coastline. All interests along the US east coast will need to monitor the forecast as we head through the upcoming work week.

Tornadoes Possible on Sunday

July 26, 2014
Mid Atlantic under a Slight Risk for Severe thunderstorms on Sunday; image courtesy NOAA Storm Prediction Center (SPC)

The Mid-Atlantic is under a slight risk for severe thunderstorms on Sunday; image courtesy NOAA Storm Prediction Center (SPC). 

As of today, the Storm Prediction Center (SPC) has placed the Washington Region under a slight risk for severe thunderstorms on Sunday. A thunderstorm complex originating from the midwest may impact the DC Area during the pre-dawn or morning hours on Sunday, that is if they survive the trip over the Appalachian mountains. There may be a break in the action during the late morning and early afternoon hours.  During the late afternoon and evening hours, wind shear will be increasing and a cold front will approach the region from the west. Thunderstorms may become super cells Sunday afternoon and evening, producing damaging winds, large destructive hail and tornadoes.

Latest North American Model (NAM) showing helicity values (wind shear) increasing Sunday Afternoon and Evening.

North American Model (NAM) showing helicity values (wind shear – darker blue colors) increasing Sunday Afternoon and Evening. (Frame number three is 00z Monday, or Sunday around 6/7PM)

North American Model (NAM) showing EHI values (Energy Helicity Index) increasing Sunday afternoon and evening, especially across the southwestern suburbs.

North American Model (NAM) showing EHI values (Energy Helicity Index) increasing Sunday afternoon and evening, especially across the southwestern suburbs.

The following quote is from the National Weather Service technical forecast discussion posted today (Saturday, July 26th):

“THE COLD FRONT IS EXPECTED TO PRODUCE DISCRETE STRONG TO SEVERE
CELLS ACROSS THE OHIO VALLEY SUNDAY AFTERNOON. THIS ACTIVITY WILL
TRACK EASTWARD AND REACH THE POTOMAC HIGHLANDS SUN LATE AFTERNOON
REACHING THE INTERSTATE 95 CORRIDOR AFTER 8 PM. AHEAD OF THE FRONT
THUNDERSTORMS ARE EXPECTED ALONG OUTFLOW/DIFFERENTIAL HEATING
BOUNDARIES FROM DEPARTING MCS.

THE ATM [atmosphere] WILL BE CONDUCIVE FOR SEVERE
THUNDERSTORMS CAPABLE OF SUPERCELLS. CURVED HODOGRAPHS WITH 50KTS OF
SHEAR WILL LIKELY CAUSE DMG WINDS…LARGE HAIL AND TORNADOES.
SUPERCELLS WILL BE CAPABLE OF SPAWNING A COUPLE TORNADOES.
THESE
SIGNALS ARE STRONGER THAN THE MID-ATLANTIC USUALLY WITNESSES.
PLEASE USE CAUTION SUNDAY AND SUNDAY NIGHT AND MAKE SURE YOU ARE
NEAR AN OUTLET TO RECEIVE UP TO DATE WEATHER INFORMATION.

Residents should have their weather radios on standby and stay abreast to the latest forecasts from the National Weather Service in case severe thunderstorms impact your area.

A Look Ahead at Temperatures through the Final Days of Spring

May 31, 2014

What a spectacular Spring it has been across the Mid-Atlantic with periods of low humidity and mild temperatures more similar to what you would find in New England during this time of year.

Below are four images taken from the latest climate forecast system (CFS) model specifically looking at the possible temperatures (departure from normal in Celsius) through June 20th. While there will be periods of heat and humidity, it looks as though there will also be periods with low humidity and cooler temperatures.

Temperature Departure from Normal May 31 - June

Temperature Departure from Normal (Celsius) May 31 – June 5th

Temperature Departure from Normal May 31 - June

Temperature Departure from Normal (Celsius) June 05 – June 10

Temperature Departure from Normal May 31 - June

Temperature Departure from Normal (Celsius) June 10 – June 15

Temperature Departure from Normal May 31 - June

Temperature Departure from Normal (Celsius) June 15 – June 20 (last day of Spring)

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