A very active Sunday shaping up out there with severe weather potential high. There is a tornado watch until 7 PM which extends into St. Francois County MO and covers much of central MO (red) and a severe thunderstorm watch until 10 PM for the entire western district and covers much of western Mo and eastern KS (blue).
There is plenty of moisture in the air with dew points to summer like levels over the region and a sharp drop off over central KS where winds turn westerly behind a cold front.
We’ve got two areas of thunderstorms we’re watching. The first from NC to SC Missouri moved through KC around lunchtime. It’s heading into 70 and 80 degree air over eastern MO and southern IL which will help the storms maintain their strength. The second area is over east central KS and is much more scattered and recently developed. This is right along the cool front. Notice temps in the 60s and 70s over the western district, dropping sharply into the 50s and 40s over KS. This air is just behind the first wave and that’s taken a little energy out of the air.
Skies are clearing though, so there is some heating taking place ahead of this line.
The bottom line is be weather aware as we head through the afternoon and nighttime. The first wave may reach the eastern district late afternoon and evening, and depending upon how the line evolves, it is possible the watch could be extended into IL. Also, additional storms will sometimes form ahead of the leading line of thunderstorms. For the western district, arrival time of the KS line is also late afternoon or evening, and we’ll have to watch how this line maintains itself as it enters areas which were rain-cooled earlier today and if skies can clear fast enough before the cloud blow-off from the new storms removes the opportunity for some sunshine and heating ahead of the line. Current indications are this line may be more scattered than the first wave and not all areas will be impacted, but again, remain weather aware.
The lack of rain in the week which closed at 7 AM Tuesday (May 5), (which is when the cutoff for the data used by the U.S. Drought Monitor in making these maps) led to little change to the drought situation in the west, aside from a slow creep northward into Cass and Johnson Counties in MO. The biggest change was the expansion of dryness west across south central Missouri and the Ozarks which is starting to reach toward the eastern forecast district.
St. Louis is -0.66 for the month and -0.94″ for 2015 through 12AM today. (not including today’s rain).
Kansas City is +0.25 for the month and -2.00″ for 2015 through 12AM today. (not including today’s rain).
Week In Review:
Warmth was concentrated in the eastern U.S., with cool weather in the High Plains, Rio Grande, Florida and in the Southwest. Several atypical rain events impacted the Southwest, where May and June are usually the hottest, driest months. The PACNW was also warmer than average.
Several thunderstorm events unfolded for the week, particularly in the west, where a severe thunderstorm watch was issued on Monday and heavy rain tracked over the northwest half of the western district into Tuesday.
This a a radar-estimated rainfall total ending Tuesday morning:
The southern half of the district did not really get much if any rain as the band lifted north with time. General rains fell in the eastern district on Saturday with some thunder and lightning:
Here’s a look at this weeks rains ending at 7AM this morning (so this does not count today’s rain):
Healthy totals in the east this week:
Much healthier totals in the west as well.
Severe weather remained concentrated over TX/OK with some strong tornadoes very near Oklahoma City. Here are some radar images of the classic “Hook” echo of a storm with a strong tornado (click to make them more readable). The second two images are winds, and show wind fields around the storm (blue toward or inbound and red or outbound) away from the radar site which was very near the tornado. OK City is just NNE of this storm and Moore, OK (where there have been repeated destructive tornadoes is just north of the storm on I-35.
The tropics turned active this week with the developing systems mentioned last week continuing to organize. Tropical Depression 06W developed into Typhoon Noul which made landfall on the extreme northeast tip of the Philippine Island of Luzon as a Super Typhoon with 130 kt winds. Noul is forecast to gradually weaken as it curves northeast to the east of Japan this week and transitions into a mid latitude storm system over the north Pacific. Here are some shots of Noul as it approached peak strength and grazed Luzon.
Tropical Storm Dolphin (07W) developed further west of Noul over the Marshall Islands. Dolphin developed within 5 degrees of the equator and it’s circulation extended south of the equator. Here are some images of the very large system. As is typical with these large systems they are slow to organize and develop, but TS Dolphin is forecast to become a typhoon and track near Guam by late in the week. We’ll update that on next week’s blog.
Closer to home, the Atlantic season started early with a low pressure area near the Bahamas evolving into Subtropical Storm Ana, which then became Tropical Storm Ana. Subtropical storms are hybrid storms having some characteristics of “run of the mill” low pressure areas and tropical cyclones. Here is a series of satellite images showing the low which would become Ana developing, transforming into a tropical storm and making landfall very near the SC/NC border. Ana developed, thanks in part to warmer than average waters off the southeast coast in the Gulf Stream and developing under a cold-core upper low which made the atmosphere more unstable than would be typical for tropical cyclone formation. (This can be a typical scenario for subtropical cyclone formation).
Here are a few radar images of Ana, which was trying for a time to close off an eye-like feature, but was fighting off dry air. The red/blue image is a Doppler radar image of the wind flow with blues/purples flow inbound toward the Wilmington NC radar and reds flow outbound (away) from the radar.
The North Atlantic Hurricane season doesn’t begin until June 1, with the eastern Pacific season starting late this week. Just to recap; here are the next few names on the northern Hemisphere TC list:
Here are the next names for the Atlantic this year: Bill, Claudette, Danny and Erika.
In the Eastern Pacific (out to 140W): Andres, Blanca, Carlos and Delores.
In the Central Pacific (140W to the Dateline): Ela, Halola, Iune, Kilo
In the Western Pacific (180E to Asia): Kujira, Chan-hom, Linfa, Nagka.
In the North Indian Ocean: Ashobaa, Komen, Chapala, Megh.
Storms crossing from one ocean to another which remain a tropical cyclone keep their original name.