King Lightning

We are winding down the Summer lightning season, but before we call it good – we have what appears to be several chances of activity this week.  Including last evening when a supercell storm formed near Watonga and moved slowly southeastward.

I totally misjudged this event and should have been out the door an hour earlier.  Still, I was able to see some decent cloud to ground lightning and anvil crawlers before the storm rapidly weakened.

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Part of what caused my distraction this afternoon was dealing with an addition to the household.  Meet “King” -

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More images of King can be found at
http://www.pbase.com/okweatherwatch/king

Thanks for the fun Hermine!

Well… it was fun to keep track of “Hermine” as it made its way

from the western gulf – through Texas – and finally through Oklahoma.

Mainly because, it just doesn’t happen very often.  And what was more cool,

was that Hermine managed to make it to Okarche.  Right on top of.  Yes,

for a period this early morning… winds went totally calm and we had the

lowest pressure in the state as the remnant low passed overhead between

2 and 3 A.M.  This “eye” wasn’t nearly as memorable of an event as what people

along the coastal waters get to see… but remember, this is central Oklahoma for

goodness sakes.  Goodbye Hermine – glad to make your acquaintance… and we

appreciated what rain we got for sure!

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Remnants of “Hermine” poised to move over Okarche tonight…

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A well defined low pressure area has developed late this evening near the southwest corner of Canadian County… or about 25 miles southwest of Okarche.  In all likelihood… this low will track over Okarche during the next few hours.

Most of the heavy precipitation has been confined well east and south of the low center.  So, we don’t expect much more in the way of heavy rain tonight.

Winds in Okarche did get gusty out of the east as the pressure has fallen to 29.72 inches.

As of midnight… 1.13 inches of rain has fallen.  Combined with the 0.54 of an inch yesterday… this storm total has been brought up to 1.67 inches.  A bit more rain is possible after midnight….but it shouldn’t be much.

“Hermine” center becoming difficult to locate

Trying to find the exact center of the low pressure area is becoming more and more difficult.  There are still radar indications that it could be located over eastern Caddo County… however, there is a strung out area of low pressure in mesonet data that extends east across Grady County.  The lowest pressure is at Chickasha and it is believed that this is where the center is likely reorganizing.  To what extent it reorganizes remains to be seen.  Dry air is evident on water vapor satellite imagery spreading into southwest Oklahoma which will continue to erode precipitation on the southwest side of the system.

An arc of heavy thunderstorms extends from northern Grady County to Pontotoc County to Marshall County.  A small supercell storm formed near the southeast corner of McClain County… however, this storm has weakened as it has moved into the southwest corner of Pottawatomie County.

A heavy rain and flooding threat will continue south and east of the metro area for the next several hours.

At 9:50 P.M…. the lowest pressure was 29.70 inches.

“Hermine” still in Comanche County

While I continue to refer to this system as “Hermine” – it has been many hours since it has been recognized by the National Hurricane Center as an organized system – having lost the necessary tropical characteristics to be considered a Tropical Depression.  Still, I feel that it warrants being referred to as something other than just “a low pressure area”.  So, I will continue to call this system “Hermine”.

At 8:50 P.M., careful examination of data from the TOKC TDWR shows a circulation center very close to Elgin in Comanche County.  This matches well with data from the Oklahoma Mesonet – meaning that Hermine has drifted only a few miles north over the past hour.  Three hour pressure falls are greatest over northern Grady County and Hermine should begin to move more to the northeast soon.

Rainfall totals are starting to become impressive with a swath of 4 to greater than 5 inch amounts observed from southern McClain to southern Grady Counties.  Also… greater than 4 inches of rain has fallen in parts of Love County.

The tornado threat has lessened over the past hour… but a few small supercells are still noted from eastern Love County northward to eastern Garvin and western Pontotoc Counties.

The greatest rainfall amount today: 5.09 inches at Acme in Grady County.

Current lowest pressure: 29.68 inches.

The highest wind with the system occurred around Noon at Ninnekah in Grady County – 47 M.P.H.

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“Hermine” getting ready to move northeast out of Comanche County

At 7:50 P.M., the center of the circulation was over eastern Comanche County – just south of Elgin.  This indicates a little turn to the right over the past hour.  Very heavy rainfall continues in Grady, McClain and Garvin Counties where a Flash Flood Warning is in effect.

A Tornado Warning is in effect for eastern Love County where an isolated supercell is moving quickly northeast.  This storm produced a tornado earlier near Gainesville, Texas.

The lowest pressure remains near 29.68 inches.

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“Hermine” makes it to Oklahoma

At 5:50 P.M… the center of what is left of “Hermine” has crossed the Red River into southwest Oklahoma.  The circulation is very close to Grandfield where winds have become calm and the pressure has dropped to 29.69 inches.

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Most of the heavy rainfall has been confined to southern Oklahoma where several places have seen over three inches of rain during the past 24 hours.

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“Here she come!”

At 7:00 A.M. this morning… the center of “Hermine” is well onshore in south Texas and is maintaining a well defined circulation.  Winds are probably quite gusty in the remaining eyewall circulation.  A large area of heavy rain is found in central and south Texas and the leading edge is now pushing into the Dallas/Fort Worth area.

Overnight model guidance from over 50 sources is well clustered and suggests high confidence in the forecast track heading first toward western north Texas and then northeast across western Oklahoma.  Flash Flood Watches now extend to the Kansas/Oklahoma border.

Hermine shouldn’t linger too long in Oklahoma which will limit the overall rainfall a bit.  Still, two to four inches of rain look likely across a large part of the state and local amounts of six inches or more are possible.  This will be a true tropical rain falling through an atmosphere that will be nearly saturated through the entire sounding.

Some of the heaviest rain to ever fall in Oklahoma has been associated with tropical systems.  And, climatology favors late summer and fall for these events.  It appears that the speed Hermine moves through will be the main limiting factor for record rainfall potential.

Depending upon the structure of the system as it moves through – there will still be a chance at severe weather in the form of gusty winds and isolated tornadoes.  The threat will be greatest if rainbands are able to break up sufficiently to allow a bit of sunshine which could enhance the low level instability.

Stay tuned!

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Hoping “her-MEEN” Means Business…

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NOW we have something good to talk about!  Model data over the past couple of days has been amazingly consistent with regard to the development of a tropical cyclone in the western gulf and its movement northward into Oklahoma by mid-week.  Indeed, Tropical Depression 10 became “Tropical Storm Hermine” earlier this morning.  Hermine is pronounced her-MEEN.  Steady intensification has occurred during the past 18 hours and this has forced the National Hurricane Center to issue a Hurricane Watch for portions of south Texas.  It remains to be seen if Hermine can reach Hurricane strength… however, no doubt remains about it being a well developed tropical system.  Systems such as these are capable of producing copious amounts of rain well after making landfall.

The various tropical cyclone model data is in pretty good agreement in moving the system northwestward through Texas before turning it northeast across Oklahoma.  The cluster of path forecast leans a little more toward western Oklahoma, but this would still put the heaviest rainfall over most all of the state just to the east of the center.  It’s very cool to see tropical cyclone forecast paths in this part of the world!

Track Guidance

This mornings NAM – takes the center of the system over Okarche during the early morning hours Thursday, and produces a large swath of three to five inch rain over most of the state.

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The official Hurricane Center forecast maintains Hermine as a Tropical Depression over northwest Oklahoma by daybreak Thursday.  It is hard to believe that we may be going from mild drought to a flash flooding situation during the next few days.

Hermine Forecast - NHC

Unlike the 2007 system – Erin – Hermine is unlikely to regenerate to Tropical Storm strength.  However, depending on the structure – it may still be capable of producing gusty winds upward of 45 M.P.H. in rainbands.  And, as the forecast low level shear below indicates, there could even be isolated tornadoes.

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We are still a few days away and errors in the track forecast this far out can be great.  But, at least we have something to talk about!

Okarche, Oklahoma