7:00 AM | Cool pattern lasts into early next week with late night and early morning clouds, fog and afternoon clearing
6-Day Forecast
Today
Early morning clouds and fog give way to gradual clearing, breezy and cool, highs in the upper 60’s
Tonight
Becoming mostly cloudy, mild, breezy, fog late, lows in the upper 50’s
Saturday
Patchy fog early then becoming mostly sunny, still cool and breezy, mid-to-upper 60’s
Saturday Night
Mostly cloudy, mild, some fog possible late, upper 50’s
Sunday
Early low clouds and fog possible then partly sunny skies, cool, mid 60’s
Monday
Patchy fog then partly sunny skies, cool, mid-to-upper 60’s
Tuesday
Patchy fog then partly sunny skies, cool, mid 60’s
Wednesday
Patchy fog then partly sunny skies, still cool, mid-to-upper 60’s
Discussion
Below normal temperatures are likely for the upcoming holiday weekend as marine flow of air continues the pattern of late night and early morning low clouds and fog along coastal locations. Some slight warming is possible by the latter part of next week as offshore winds may re-develop.
Video
7:00 AM | Stays on the cool side through the weekend with a marine flow of air in place
6-Day Forecast
Today
Early morning clouds then gradually becoming mostly sunny, cool, windy, highs in the middle 60’s
Tonight
Becoming mostly cloudy, mild, fog possible late, lows in the upper 50’s
Friday
Early morning low clouds and fog then becoming mostly sunny, still cool and breezy, mid-to-upper 60’s
Friday Night
Mostly cloudy, mild, some fog possible late, upper 50’s
Saturday
Early low clouds and fog possible then partly sunny skies, cool, mid 60’s
Sunday
Patchy fog then partly sunny skies, cool, mid-to-upper 60’s
Monday
Patchy fog then partly sunny skies, cool, mid 60’s
Tuesday
Partly sunny skies, still cool, mid-to-upper 60’s
Discussion
Below normal temperatures are likely for the upcoming holiday weekend as marine flow of air continues the pattern of late night and early morning low clouds and fog along coastal locations. Some warming is possible by the middle part of next week as offshore winds develop.
Video
7:00 AM | Cooler and breezy weather continues today and right into the upcoming holiday weekend
6-Day Forecast
Today
Early morning low clouds and fog then gradually becoming mostly sunny, cool, breezy, highs in the middle 60’s
Tonight
Becoming mostly cloudy, mild, fog and drizzle possible late, breezy, lows in the upper 50’s
Thursday
Early morning low clouds, fog and drizzle then becoming mostly sunny, still cool and breezy, mid-to-upper 60’s
Thursday Night
Mostly cloudy, mild, some fog possible late, upper 50’s
Friday
Early low clouds and fog possible then partly sunny skies, cool, mid-to-upper 60’s
Saturday
Patchy fog then partly sunny skies, cool, mid-to-upper 60’s
Sunday
Patchy fog then partly sunny skies, cool, mid 60’s
Monday
Partly sunny skies, still cool, mid-to-upper 60’s
Discussion
A cooling trend began across the region on Tuesday as onshore flow reformed along coastal locations and highs will generally be confined to the 60’s for the next several days along with a stiff breeze. The return of the marine air has brought back the usual pattern of late night and early morning low clouds and fog along coastal sections and there can even be some late night drizzle as well.
One final note: the tornado that struck Oklahoma on Monday has now been upgraded to an "EF-5" classification level which is the most intense type on the "Enhanced Fugita" scale and it is suggestive of 200+ mph winds.
Video
12:45 PM | More on the Monday “EF-4 ?” tornado in Oklahoma
Discussion
Tornadoes require clashes of air masses to form generally to include cold, dry air in the upper atmosphere and very warm and humid air in the lower atmosphere. For much of the spring, the missing ingredient for this scenario in the US was the influx of very warm and humid air from the Gulf of Mexico thanks in large part to the persistent cold pattern in the central and eastern US that acted to inhibit Gulf of Mexico air from advancing northward. The cold air masses, however, began to retreat a couple of weeks ago and subsequently, dew points, which are a true measure of moisture content in the air, have consistently climbed in the central and eastern US and this increased dramatically the prospects for severe weather.
Indeed, the combination of very warm and humid low-level air with a vigorous cold upper-level low pressure trough on Monday helped to spawn the powerful tornado that struck portions of Oklahoma with a major impact on Moore, a heavily populated (50,000 residents) suburb of Oklahoma City some twenty miles to its south. The preliminary estimate is that the one-to-two mile wide tornado that struck the town of Moore reached EF-4 status on the “Enhanced Fugita” scale (5 being the most intense) with winds of nearly 200 mph, but these estimates will be re-evaluated over the next several days/weeks as tornado experts on the ground closely assess the damage and I think it may very well end up being classified as an EF-5. The tornado lasted for about 40 minutes causing destruction over a 20 mile swath.
The overall weather pattern that helped to produce the severe weather yesterday (i.e., warm, humid low level air, strong cold upper-level low with a powerful jet streak, strong surface cold front) will continue for the next couple of days with the severe weather threat zone slowly shifting eastward. There is a threat today for severe weather from the southern Plains to the Upper Midwest, and then likely in the Ohio Valley on Wednesday, and then perhaps in the Mid-Atlantic and Northeast US late Thursday as a strong cold front approaches the east coast. Strong-to-severe thunderstorms are possible later Thursday in the region from the Carolinas to New England as all the atmospheric dynamics shifts towards the east coast. This afternoon’s video includes some time-lapse video of yesterday’s tornado and a detailed discussion as to why the previously quiet tornado season has ended.
Video
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About Paul Dorian
Paul Dorian, meteorologist with the SI, provides detailed forecasts for employee locations in the Mid-Atlantic region. Learn more...