General Weather Discussion - June 2015

[Bunty]

This tiny little popcorn storm just dumped a ton of water on Harrah for about 10 minutes. Gone as quickly as it appeared though.

The same thing happened this afternoon on the east side of Stillwater, but didn't come with a ton of water, just .07". It currently looks like something heavier might be headed for Stillwater, assuming it doesn't bypass or fizzle out first.

[Bunty]

I wish I was smarter...can't understand nothin'...*

What's Invest91 about?

An invest is an area of disturbed weather for which the National Hurricane Center is interested in collecting special data, such as microwave satellite imagery and specific model guidance. While the NHC says that designating a disturbance as an invest "does not correspond to any particular likelihood of development of the system into a tropical cyclone, it is generally known that if the NHC designates an invest, that system is of interest to them, and usually has at least a low chance of subtropical or tropical development.

[jn1780]

Our current conditions seem somewhat similar to what we had in 2007 when Tropical storm Erin came through. The wet summer in Oklahoma and Texas actually allowed the storm to survive longer giving us a lot more heavy rainfall.

[Anonymous.]

GFS is doomsday for Eastern 2/3 of OK this week with the tropical system. NAM keeps it locally to eastern OK for now.

Either way, someone will be flooding.

[Bunty]

FLASH FLOOD WATCH IS BACK:

Flash Flood Watch
Updated: Mon Jun-15-15 02:47pm CDT
Effective: Mon Jun-15-15 02:47pm CDT
Expires: Thu Jun-18-15 07:00pm CDT

Severity: Severe
Urgency: Expected
Certainty: Possible

Status: Actual
Type: Alert
Category: Met
Areas affected: Atoka; Bryan; Canadian; Carter; Cleveland; Coal; Garvin; Grady; Hughes; Jefferson; Johnston; Kingfisher; Lincoln; Logan; Love; Marshall; McClain; Murray; Oklahoma; Payne; Pontotoc; Pottawatomie; Seminole; Stephens

Instructions: Monitor weather forecasts and information. Make plans to get to higher ground if flooding happens.

Message summary: ...areas of flooding are expected to develop across portions of central and southern oklahoma and northern texas through thursday evening...
.heavy rainfall will develop across portions of oklahoma and northern texas tonight through thursday. The heaviest rainfall will develop tuesday evening through thursday in response to the remnants of a tropical disturbance moving across the region.
...flash flood watch in effect through thursday evening...
The national weather service in norman has issued a
* flash flood watch for portions of oklahoma and northern texas...including the following areas...in oklahoma...atoka...
Bryan...canadian...carter...cleveland...coal...gar vin...
Grady...hughes...jefferson...johnston...kingfisher ...lincoln...
Logan...love...marshall...mcclain...murray...oklah oma...
Payne...pontotoc...pottawatomie...seminole and stephens. In northern texas...clay.
* through thursday evening
* two periods of heavy rainfall are anticipated through thursday. The first will develop this afternoon and overnight across central and southern oklahoma... Persisting through tuesday morning. Hourly rainfall rates of two to four inches an hour will be common. The second round will develop tuesday evening through thursday as the remnants of a tropical disturbance moves into the southern plains. Two to six inches of rainfall can be expected across the watch area through thursday evening.
* the ground remains saturated from recent rainfall. It will not take much for flash flooding to develop.

[Bunty]

The corner of SW Oklahoma has had over 10 inches of rain in the past 7 days:

[okatty]

They may have had single years where they don't have that much rain! WOW.

[John1744]

Seeing a lot of graphics going around tonight talking about how much rain we may be getting.

Ugh.

[Anonymous.]

GFS and NAM have switched from yesterday.

NAM takes track more into C OK

GFS is mostly E OK.

[bradh]

GFS has that thing doing a big turn. Going further west into Texas and then turning sharply NE.

The overreactions in Houston are epic right now. I love when there is a weather freak out there, my Facebook feed is hilarious. Tons of bleach jokes.

[LocoAko]

I imagine the flooding if this verifies could be devastating. This gradient is going to be a blast to track and forecast... doh.

[venture]

Tagging on to Loco's images...my discussion for Bill.

Tropical Storm Bill details. Heavy rain should be entering Oklahoma in the next couple of days. The center of the remnants of Bill is expected to enter Oklahoma by late Wednesday. 00Z NAM has the center of the low entering SW OK just to the east of Wichita Falls by 7PM Wednesday. The low then tracks up to Norman/OKC by Midnight to 1AM. it slowly moves off to Tulsa by 9AM and exits NE OK by 7PM. NAM total rainfall amounts are generally 3 inches plus along and east of of a line from Frederick - OKC - Osage County. Pockets of heavier rain, possibly exceed 7 to 10 inches from Lawton to OKC/Norman to just west of Tulsa and also up in far NE OK around Miami.
The GFS track is not much different, maybe a hair further east. It also has Bill into OK by mid afternoon Wednesday and out by Thursday afternoon. Rainfall amounts generally on the same scale as the NAM, it even paints some over 10 inches over the SE OKC Metro area.
Obviously main threat is going to be significant flooding. As witnessed on Monday, Norman had a heavy downpour for a relatively short period of time and still water rescues were needed along some city streets. The area simply cannot handle significant rainfall, but it doesn't look like we'll have a choice.
Secondary threat will be the chance for a few isolated tornadoes, albeit weak (more than likely) especially in the eastern hemisphere of the system. Typically we see this more so along the coast and near inland areas with landfalling systems, but there could be enough low level spin still to allow for a few quick spin ups.

[OKCisOK4me]

And as the Mets on TWC said, "dry begets dry, wet begets wet". We're so saturated that it's not helping. It's gonna be similar to TS/TD Erin.

[soonerguru]

Well, it's gonna rain.

[OKCisOK4me]

Well, it's gonna rain.

Astute observation...

[venture]

Marginal Risk of severe weather Today and Wednesday. Main risk today winds to 60 mph. Main risk on Wednesday will be some tornadoes in stronger cells/bands.

Today...

...PARTS OF SOUTHEAST AND EAST TX...
A BROAD CORRIDOR OF 30-45 KT SSELY LOW-LEVEL WINDS WILL SPREAD NWD
ACROSS THIS REGION TODAY ALONG AND EAST OF THE INLAND TRACK OF
TROPICAL STORM BILL. MARGINAL-MODERATE INSTABILITY AND ENHANCED
LOW-LEVEL SHEAR ATTENDANT TO THE LOW-LEVEL WIND FIELD SUGGEST A
TORNADO THREAT CANNOT BE RULED OUT WITHIN THE NORTHEAST QUADRANT OF
TROPICAL STORM BILL.

...ERN OK/OZARKS THROUGH OH VALLEY TO MID-ATLANTIC STATES/SRN NEW
ENGLAND...
LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE AGAIN TODAY AS STORMS
DEVELOP WITHIN THIS CORRIDOR OF THE WARM SECTOR AND AHEAD OF THE
COLD FRONT IN THE NORTHEAST STATES TO OH VALLEY...WHERE THE AIR MASS
REMAINS MOISTURE-LADEN WITH WEAK MIDLEVEL LAPSE RATES. PORTIONS OF
THIS REGION MAY NEED HIGHER SEVERE WIND PROBABILITIES IN LATER
OUTLOOKS IF CONFIDENCE INCREASES FOR THE DISCERNMENT OF STRONGER
INSTABILITY.

Tomorrow...


...NERN TX/ERN OK VICINITY...
AS REMNANTS OF BILL DRIFT SLOWLY NWD...BANDS OF SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO AFFECT PARTS OF THE SRN PLAINS
AREA...BRINGING LOCALLY HEAVY RAINFALL TO MANY AREAS. IN
ADDITION...ENHANCED LOW-LEVEL SHEAR E OF THE CIRCULATION CENTER --
PARTICULARLY IN THE NE QUADRANT -- WILL MAINTAIN SOME RISK FOR
ISOLATED/BRIEF TORNADOES WITH STRONGER CELLS WITHIN THE CONVECTIVE
BANDS. WILL MAINTAIN ONLY 5% RISK ATTM /PRIMARILY FOR
TORNADOES/...WHICH COULD BE UPGRADED TO SLIGHT RISK IN LATER
FORECASTS.

[Bobby821]

Tagging on to Loco's images...my discussion for Bill.

Tropical Storm Bill details. Heavy rain should be entering Oklahoma in the next couple of days. The center of the remnants of Bill is expected to enter Oklahoma by late Wednesday. 00Z NAM has the center of the low entering SW OK just to the east of Wichita Falls by 7PM Wednesday. The low then tracks up to Norman/OKC by Midnight to 1AM. it slowly moves off to Tulsa by 9AM and exits NE OK by 7PM. NAM total rainfall amounts are generally 3 inches plus along and east of of a line from Frederick - OKC - Osage County. Pockets of heavier rain, possibly exceed 7 to 10 inches from Lawton to OKC/Norman to just west of Tulsa and also up in far NE OK around Miami.
The GFS track is not much different, maybe a hair further east. It also has Bill into OK by mid afternoon Wednesday and out by Thursday afternoon. Rainfall amounts generally on the same scale as the NAM, it even paints some over 10 inches over the SE OKC Metro area.
Obviously main threat is going to be significant flooding. As witnessed on Monday, Norman had a heavy downpour for a relatively short period of time and still water rescues were needed along some city streets. The area simply cannot handle significant rainfall, but it doesn't look like we'll have a choice.
Secondary threat will be the chance for a few isolated tornadoes, albeit weak (more than likely) especially in the eastern hemisphere of the system. Typically we see this more so along the coast and near inland areas with landfalling systems, but there could be enough low level spin still to allow for a few quick spin ups.

Is the track still on the same course as it was when you posted this Venture?

[Anonymous.]

Yea, both NAM and GFS have come to agreement to take the heaviest precip. gradient from about I-44 and just east of it.

Being on the west side of this gradient is going to be a feast of famine scenario, so OKC could be slammed or it could stay just off to the east, Think Newalla to Shawnee area.

It will be fun to track, indeed.


Also don't forget we will likely see tornado watch for quick spinups along the eastern corridor of the Low, wherever it ends up.

[Bobby821]

So Moore and the south Metro will be in the heavy rain from this correct?

[jn1780]

At least this isn't coming in directly from the west like Erin.

[venture]

Exact track of the low is still not set. Model guidance this morning has shifted east a bit more as has the official NHC forecast.

12Z NAM - Arrives over Marietta / Ardmore by 5-6PM tomorrow. Track over to McAlester then to Fort Smith.
06Z GFS - Wichita Falls to Norman to Tulsa to Fayetteville track.

Track will play a big key as the precip gradient is going to be huge - think like some of our winter storms.

Tornado risk will be highest in the part of the system with the greatest helicity. Models put this in the Northern and Eastern sections of the storm. If we look at the 12Z NAM for 5PM tomorrow...the area outlined is where the risk would be there (although not set in stone).

[OKCisOK4me]

Last night when they first issued the flash Flood watch, Oklahoma County was the most north and west county in the watch. Now I see they've added Logan, Kingfisher, and Canadian.

[venture]

12Z GFS track almost identical to NAM. Gradient will be tight. Norman might be 6 inches or more and Yukon could have less than an inch.

[Bunty]

Exact track of the low is still not set. Model guidance this morning has shifted east a bit more as has the official NHC forecast.

12Z NAM - Arrives over Marietta / Ardmore by 5-6PM tomorrow. Track over to McAlester then to Fort Smith.
06Z GFS - Wichita Falls to Norman to Tulsa to Fayetteville track.

Track will play a big key as the precip gradient is going to be huge - think like some of our winter storms.

Tornado risk will be highest in the part of the system with the greatest helicity. Models put this in the Northern and Eastern sections of the storm. If we look at the 12Z NAM for 5PM tomorrow...the area outlined is where the risk would be there (although not set in stone).

Speaking of huge precip gradients:

[kelroy55]

Yeah sorry, got distracted and didn't finish my thoughts very well. Developing tropical system could move up over OK the next few days. When this happens, a large amount of tropical moisture will come with it and the remaining system will have enough lift to cause showers/storms to keep forming. Severe weather usually doesn't come with this, outside of a tornado threat due to enhanced low level spin around the low - but flooding is really going to be our concern with this one.

Down here in DFW they are calling for 4-6 inches and more in other areas. It's raining now and they are saying Bill will tomorrow morning just before rush hour.