1:10 PM | Atlantic tropical season about to get underway

Discussion

The 2013 Atlantic tropical season officially begins this Saturday, June 1st, and continues until November 30th. Of course, this timetable is a “man-made” one and Mother Nature can begin and end any time she wants to with respect to the formation of Atlantic tropical storms, but all-in-all, these are pretty reasonable choices for the beginning and end dates of the tropical season based on historical data.

Fortunately, it has been nearly 8 years since a major hurricane (i.e., category 3, 4 or 5) has struck the US which is the longest such period since the Civil War. In fact, Hurricane Wilma was the last major hurricane to hit the US back in October of 2005, the year that was the most active Atlantic hurricane season in recorded history and featured seven major hurricanes. Unfortunately, 2013 promises to be an active tropical season and the US east coast is vulnerable to a major hurricane hit based on some similarities in oceanic temperature patterns to analog years that were very active along the coast. Specifically, the current sea surface temperature anomalies in the northern Pacific (cold phase, negative Pacific Decadal Oscillation) and northern Atlantic (warm phase, positive Atlantic Multidecadal Oscillation) resemble closely many of the years in the decade of the 1950’s and there were numerous major hurricane hits during that time period. For example, in just the time between August 1954 and September 1955, there were five major hurricanes that struck the US east coast – Carol, Edna, Hazel, Connie and Ione. This certainly raises a red flag of warning along the east coast for the upcoming tropical season, and perhaps for the next few years as well.

I believe that the tropical season has a good chance of getting underway fairly quickly during the month of June – perhaps even as early as next week there could be some activity in the Caribbean Sea. Sea surface temperatures continue to be largely above normal across much of the tropical Atlantic and this is a primary cause of concern for an active season. (For more details on the tropical and Mid-Atlantic summertime outlooks and a comprehensive video discussion go to "Seasonal Forecasts" on the right panel).

Here is a list of the names for the 2013 tropical season (some interesting names on the list including the one for the 4th storm):

Andrea Barry Chantal Dorian Erin Fernand Gabrielle Humberto Ingrid Jerry Karen Lorenzo Melissa Nestor Olga Pablo Rebekah Sebastien Tanya Van Wendy

7:00 AM | Great weather continues for one more day

6-Day Forecast

Today

Mostly sunny, breezy, warm, highs in the low-to-mid 80’s

Tonight

Partly cloudy, windy, mild, lows in the mid 50’s

Wednesday

Partly sunny, not as warm, chance for a shower and thunderstorm, low 70’s

Wednesday Night

Partly cloudy, cool, near 50

Thursday

Mostly sunny, cool, windy, an isolated shower or thunderstorm, upper 60’s

Friday

Mostly sunny, breezy, cool, upper 60’s

Saturday

Partly sunny, cool, isolated showers, upper 60’s

Sunday

Partly sunny, warmer, mid-to-upper 70’s

Discussion

An upper level ridge will provide another nice day in the southern Rockies with plenty of sunshine and highs well up in the 80's. An upper level trough in the west will progress towards the region by mid-week bringing some isolated showers and thunderstorms and slightly cooler conditions. It looks like it’ll stay on the cool side as we approach the upcoming weekend.

Video

httpv://youtu.be/KFm10UY5k3U

7:00 AM | Quite breezy way to start off the new work week

6-Day Forecast

Today

Early morning clouds give way to gradual clearing, windy and cool, highs in the upper 60’s

Tonight

Partly cloudy, cool, windy, lows in the upper 50’s

Wednesday

Becoming mostly sunny, still cool and breezy, mid-to-upper 60’s

Wednesday Night

Mostly clear, cool, breezy, upper 50’s

Thursday

Partly sunny skies, pleasant, near 70

Friday

Mostly sunny skies, pleasant, mid 70’s

Saturday

Mostly sunny skies, milder, mid-to-upper 70’s

Sunday

Mostly sunny skies, pleasant, low 70’s

Discussion

Quite breezy conditions will begin the new work week, but a warming trend will develop by mid-week and last right into the upcoming weekend with plenty of sunshine expected for the second half of the week along with pleasant temperatures.

Video

httpv://youtu.be/KFm10UY5k3U

7:00 AM | Great holiday weekend shaping up with sunshine and 80+ degrees each day

6-Day Forecast

Today

Mostly sunny, windy, warmer, highs in the low-to-mid 80’s

Tonight

Partly cloudy, windy, mild, lows in the mid 50’s

Saturday

Mostly sunny, even warmer, mid-to-upper 80’s

Saturday Night

Partly cloudy, mild, mid 50’s

Sunday

Mostly sunny, warm, mid 80’s

Monday

Mostly sunny, warm, low-to-mid 80’s

Tuesday

Partly sunny, warm, isolated showers and thunderstorms, upper 70’s

Wednesday

Partly sunny, not quite as warm, isolated showers and thunderstorms, mid 70’s

Discussion

An upper level ridge will take control of our weather today and this will set us up for a nice holiday weekend with plenty of sunshine and high temperatures reaching into the 80’s across the southern Rockies.

Video

httpv://youtu.be/r2WELwFaD4Y

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

httpv://youtu.be/r2WELwFaD4Y

7:00 AM Great weather pattern shaping up for the long, holiday weekend

6-Day Forecast

Today

Partly sunny, windy, mild, isolated afternoon showers and thunderstorms, highs near 70 degrees

Tonight

Mostly cloudy, windy, cool, chance for a shower or thunderstorm, lows in the lower 50’s

Friday

Mostly sunny, warmer, near 80 degrees

Friday Night

Partly cloudy, cool, low 50’s

Saturday

Mostly sunny, warm, near 80

Sunday

Mostly sunny, warm, near 80

Monday

Mostly sunny, warm, near 80

Tuesday

Partly sunny, warm, near 80

Discussion

An upper level ridge will take control of our weather as we approach the end of the work week and this will set us up for a nice holiday weekend. In fact, the weather forecast for Friday through Memorial Day can be basically summed up with “mostly sunny and warm with highs near 80 degrees” each day in that period of time.

Video

httpv://youtu.be/pveInhfqsV0

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

httpv://youtu.be/pveInhfqsV0

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

httpv://youtu.be/phbiaaLwpZk

7:00 AM | Should turn out to be a dry and warm holiday weekend with highs near 80 degrees

6-Day Forecast

Today

Partly sunny, milder, isolated afternoon showers and thunderstorms, highs in the mid 70’s

Tonight

Mostly cloudy, cool, chance for a shower or thunderstorm, lows in the upper 40’s

Thursday

Partly sunny, pleasant, chance for a shower or thunderstorm, low 70’s

Thursday Night

Partly cloudy, breezy, cool, low 50’s

Friday

Mostly sunny, warmer, near 80

Saturday

Mostly sunny, warm, near 80

Sunday

Mostly sunny, warm, near 80

Monday

Partly sunny, warm, low 80’s

Discussion

Enough moisture will be around the region today for isolated showers and thunderstorms to form and that unsettled weather will continue into Thursday as well. By the end of the week, however, high pressure will take over and the weather will turn warmer and drier and that dry, warm weather will continue this weekend with high temperatures climbing to near 80 degrees each day.

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

httpv://youtu.be/phbiaaLwpZk

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

httpv://youtu.be/XWgG6npVG_0