As of 4:00 PM CDT, a significant flash flooding event is unfolding across parts of Arkansas, Kansas, Oklahoma, and Texas. The latest forecast discussion from the Tulsa National Weather Service (NWS) underscores this point and doesn’t mince words as to the significant dangers.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
337 PM CDT SAT MAY 23 2015 .
…LIFE THREATENING FLOOD POTENTIAL TONIGHT THROUGH SUNDAY…
WIDESPREAD CONVECTION IS UNDERWAY ACROSS THE CENTRAL AND SOUTHERN PLAINS WITHIN AN EXPANDING PLUME OF TROPICAL MOISTURE. OBSERVED RAINFALL RATES HAVE BEEN IMPRESSIVE ESPECIALLY FOR AREAS BENEATH ANY CONVECTIVE SEGMENT THAT BECOMES ORIENTATED PERPENDICULAR TO THE LOW LEVEL SOUTHERLY FLOW. FLOW ALOFT WILL CONTINUE TO BACK AS UPPER TROUGH APPROACHES WHILE DIFFLUENT REGION GRADUALLY SPREADS EASTWARD. THIS WILL ALLOW THE ONGOING CONVECTION TO EXPAND IN COVERAGE FROM WEST TX NORTHWARD INTO CENTRAL AND EASTERN OK THIS EVENING AND OVERNIGHT. RAINFALL FORECASTS MAY BE CONSERVATIVE BASED ON OBSERVED CONDITIONS THIS AFTERNOON…AND LATER UPDATES MAY NEED TO INCREASE TOTALS A BIT FURTHER ESPECIALLY FROM LATE TONIGHT THROUGH SUNDAY MORNING ACROSS EASTERN OKLAHOMA.
IMPACT: WET SOILS ALONG WITH MANY LARGER RIVERS NEAR OR CURRENTLY IN FLOOD STAGE WILL ALLOW FOR RAPID ONSET OF FLASH FLOODING. EVEN THE CONSERVATIVE RAINFALL TOTALS WILL PRODUCE LIFE AND PROPERTY THREATENING FLOODING. THE RAINFALL AXIS WILL SHIFT EASTWARD SUNDAY AFTERNOON / OVERNIGHT AND IMPACT WESTERN ARKANSAS. WHILE THE RAINFALL TOTALS MAY TAPER A BIT AS THE UPPER FORCING REMAINS LESS…THE SATURATED CONDITIONS WILL MAINTAIN THE POTENTIAL FOR DANGEROUS FLOODING. OF ADDITIONAL CONCERN WILL BE MONDAY NIGHT INTO TUESDAY AS A LARGE COMPLEX OF STORMS ORIGINATES ACROSS WESTERN TX AND SPREADS NORTHEASTWARD. WHILE THE BULK OF THIS RAINFALL IS CURRENTLY FORECAST NEAR THE ARKLATEX REGION…HEALTHY RAINFALL TOTALS ARE LIKELY TO SPREAD INTO SE OK AND WEST CENTRAL ARKANSAS WHICH WILL QUICKLY WORSEN ANY ONGOING FLOOD CONDITIONS. A LULL IN CONVECTIVE COVERAGE IS EXPECTED FOR THE MID WEEK PERIOD BEFORE A COLD FRONT AND UPPER WAVE IMPACT THE REGION BY LATE NEXT WEEK WITH MORE WIDESPREAD RAINFALL POSSIBLE.
Though rather technical in nature, the basic message behind the forecast discussion is quite simple. Over a vast area of the southern plains, a significant and potentially life-threatening flash flooding potential exists. As a result, the Tulsa NWS has also issued a Flash Flood Watch.
NATIONAL WEATHER SERVICE TULSA OK
355 PM CDT SAT MAY 23 2015
PUSHMATAHA-CHOCTAW-OSAGE-WASHINGTON OK-NOWATA-CRAIG-OTTAWA-PAWNEE- TULSA-ROGERS-MAYES-DELAWARE-CREEK-OKFUSKEE-OKMULGEE-WAGONER- CHEROKEE-ADAIR-MUSKOGEE-MCINTOSH-SEQUOYAH-PITTSBURG-HASKELL- LATIMER-LE FLORE- INCLUDING THE CITIES OF…ANTLERS…CLAYTON…HUGO…PAWHUSKA… BARTLESVILLE…NOWATA…VINITA…MIAMI…PAWNEE…TULSA… CLAREMORE…PRYOR…JAY…BRISTOW…OKEMAH…OKMULGEE…WAGONER… TAHLEQUAH…STILWELL…MUSKOGEE…EUFAULA…SALLISAW… MCALESTER…STIGLER…WILBURTON…POTEAU
355 PM CDT SAT MAY 23 2015
…FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH MONDAY MORNING…
…LIFE AND PROPERTY THREATENING FLOODING EVENT UNDERWAY…
THE FLASH FLOOD WATCH CONTINUES FOR
* PORTIONS OF EAST CENTRAL OKLAHOMA…NORTHEAST OKLAHOMA AND SOUTHEAST OKLAHOMA…INCLUDING THE FOLLOWING AREAS…IN EAST CENTRAL OKLAHOMA…CHEROKEE…MUSKOGEE…OKFUSKEE AND SEQUOYAH. IN NORTHEAST OKLAHOMA…ADAIR…CRAIG…CREEK… DELAWARE…MAYES…NOWATA…OKMULGEE…OSAGE…OTTAWA… PAWNEE…ROGERS…TULSA…WAGONER AND WASHINGTON. IN SOUTHEAST OKLAHOMA…CHOCTAW…HASKELL…LATIMER…LE FLORE…MCINTOSH… PITTSBURG AND PUSHMATAHA.
* THROUGH MONDAY MORNING
* WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OVERSPREAD MUCH OF EASTERN OKLAHOMA TONIGHT…AND SPREAD EASTWARD INTO WESTERN ARKANSAS DURING THE DAY ON SUNDAY. RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE COMMON WITH THE HEAVIEST RAINS.
* WIDESPREAD RAINFALL TOTALS OF 3 TO 6 INCHES ARE EXPECTED ACROSS MUCH OF EASTERN OKLAHOMA…ESPECIALLY AREAS ALONG AND WEST OF A LINE FROM MIAMI OKLAHOMA TO HUGO OKLAHOMA. LOCAL AMOUNTS OF 8 TO 9 INCHES WILL BE POSSIBLE WITHIN THIS SAME AREA.
LIFE THREATENING FLOODING CAN QUICKLY DEVELOP WITH THESE RAINFALL AMOUNTS…ESPECIALLY NEAR AREA RIVERS AND LAKES. BE PREPARED TO ACT QUICKLY SHOULD WARNINGS BE ISSUED FOR YOUR AREA.
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE WATER COVERS THE ROAD TO UNKNOWN DEPTHS. TAKE A DIFFERENT ROUTE TO REACH YOUR DESTINATION OR WAIT UNTIL THE WATER RECEDES.
IF YOU ARE IN THE WATCH AREA…KEEP INFORMED…AND BE READY FOR QUICK ACTION IF FLASH FLOODING IS OBSERVED OR IF A WARNING IS ISSUED. HAVE A MEANS OF RECEIVING ANY WARNINGS ISSUED OVERNIGHT SUCH AS A WEATHER RADIO.
For many parts of Arkansas, Kansas, and Texas, the flooding threat is just as significant. The latest information from your local NWS office can be obtained by NOAA weather radio or clicking your locale on this map which will take you directly to your NWS office. Obviously, the weather media (local and national) outlets of your choice have excellent information as well. Most of the flooding will take place in the Arkansas/Red Basin region. The West Gulf region is also expecting major flooding as well.
Here’s some important flash flooding safety information from the NWS. Remember, Turn Around, Don’t Drown. More people are killed every year from flooding than all other weather hazards combined. Last but not least, here’s some helpful disaster supply kit information from Ready.gov.
Stay safe and stay very weather aware during this event. With knowledge being power, you have all the information at your fingertips to keep you and your loved ones safe.
The potential for severe weather on Wednesday and Thursday is becoming more clear with the addition of new weather data to the forecast. Let me preface the rest of this post with two points. 1.) I’ve included for your convenience some severe weather safety links at the bottom of this post and 2.) it’s my hope that the information I’m sharing will alleviate some of the unnecessary anxiety and stress that is so often fostered by attention hungry fear mongers in social media. Having said that, let’s take a look at this week’s severe weather potential.
Updated 7:20 PM CDT: There is a Slight Risk tonight for parts of Kansas, Missouri, and Oklahoma with a pending watch from the Storm Prediction Center. If any storms for tonight, they could have an effect on the atmosphere in such a way that Wednesday’s severe weather outlook could be changed.
It’s no surprise that the Storm Prediction Center added an Enhanced Risk to Wednesday’s severe weather outlook. As is often the case, as more data become available, it’s easier to put the pieces of the puzzle together. Here’s a look at Wednesday’s SPC severe weather outlook. While some severe weather scenarios are almost textbook, this forecast challenge has become more daunting as the days when storms are likely has drawn closer.
Tomorrow’s severe weather setup is a very complex scenario. The next two days will certainly be no small challenge to any meteorologist. As of this post, SPC forecasters feel that storms may form much earlier than usual. This will have a significant effect on where and when any additional storms form later in the day. From the SPC discussion, “STILL..DEEP LAYER
SHEAR SHOULD BE STRONG ENOUGH FOR ORGANIZED CONVECTION…INCLUDING SUPERCELLS AND AN EVOLVING STORM CLUSTER…IN THE PRESENCE OF SIZABLE CAPE.” In other words, in spite of the fact that storms may form early, there are ingredients available for them to become potent supercells. It’s possible that if storms form early, it could be in the north-central Oklahoma/south-central Kansas border region…but that is subject to change. As the afternoon progresses, peak heating occurs, and several other elements fall into place making the atmosphere more volatile, there will be, “AN INCREASED RISK FOR SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL AND A COUPLE OF TORNADOES. INITIALLY ROUGHLY NEAR THE CENTRAL AND EASTERN KANSAS/OKLAHOMA BORDER AREA…THIS ACTIVITY IS EXPECTED TO SPREAD NORTHEASTWARD/EASTWARD TOWARD THE LOWER MISSOURI VALLEY…BEFORE GRADUALLY WEAKENING WEDNESDAY NIGHT.” Now, let’s take a look at the SPC’s severe weather probability map.
WEDNESDAY’S SEVERE WEATHER PROBABILITY MAP
As I’ve stated in previous posts, the purpose of the probabilistic map is to give people in the shaded areas an idea of their chances of seeing some kind of severe weather within twenty-five miles of a point. For parts of Kansas, Missouri, and Oklahoma shaded in red, there’s almost a one in three chance of some kind of severe weather occurring fairly close to any specific area. In the “hatched” area that’s outlined in black, there’s a higher probability of storms with a bit of extra power to their punch. The main thing to keep in mind is that if you are properly prepared for severe weather and aren’t doing anything foolishly risky, you’ll be just fine. If you live in a mobile home or will be working in a large room with a wide span roof, a barn, outbuilding, or outdoors (all typically areas that have an increased danger and are particularly vulnerable to even weak tornadoes or strong straight-line winds), you might consider planning today where you would take shelter if you’re in a warning. Outside of the red shaded area is our 15% and 5% probabilities regions which cover a large part of the southern plains to the Ohio valley. Keep in mind that storms may be very isolated in the 5% area, but can still pack quite a punch. So, to wrap up Wednesday’s outlook in lay terms…current SPC forecasts convey the possibility that some storms may get an early start. If they do form, expect them to be severe. Later in the day, the atmosphere will be primed for even more robust storms to form. Expect all modes of severe weather (aka: large hail, damaging straight-line winds, flash flooding potential, and tornadoes), numerous severe thunderstorm and/or tornado watches, and many warnings issued by your local National Weather Service office. Perhaps most importantly and once again, I can’t emphasize enough the importance of following official sources of watch and warning information.
Thursday’s severe weather outlook will be just as challenging as Wednesday’s…perhaps even more difficult…but the same hazards will be possible, especially in the Slight and Enhanced Risk areas. From the SPC discussion, “WHILE RESIDUAL CONVECTION/CLOUD COVER COULD ALTER THE LOCATION OF — OR EVEN HINDER DEVELOPMENT OF — THE NEXT ROUND OF AFTERNOON/EVENING STORMS AHEAD OF THE ADVANCING SYSTEM…IT APPEARS AT THIS TIME THAT AMPLE DESTABILIZATION WILL OCCUR AHEAD OF THE FRONT IN THE WAKE OF PRIOR PRECIPITATION. In a nutshell, in spite of widespread storms Wednesday that will have used up a lot of “energy,” the atmosphere will have plenty of time to re-charge its batteries for another round of rowdy weather. This time, the focus will be from northeastern Texas to southern Wisconsin and southwestern Michigan. The Enhanced Risk introduced yesterday by the SPC still holds. In fact, population wise, there will be almost three times as many people in the Thursday Enhanced Risk area as there were on Wednesday in spite of the fact that it is a slightly smaller area. Now, let’s take a look at Thursday’s probability map.
THURSDAY’S SEVERE WEATHER PROBABILITY MAP
Once again, the purpose of this map is to convey to you the probabilities of severe weather in or close to where you live. It’s not meant to scare or alarm anyone but, knowledge being power, to inform you so you can prepare for the possibility of storms and take necessary precautions if you’re in a warned area. The current thinking is that the highest probabilities will exist for much of eastern Missouri and most of Illinois…including the St. Louis and Chicago metro areas and surrounding suburbs. From the SPC discussion, “EXPECT SUPERCELL MODE TO EXIST — AT LEAST INITIALLY — WHICH THUS SUPPORTS INTRODUCTION OF AN SIGNIFICANT SEVERE-WEATHER AREA AND ENHANCED CATEGORICAL RISK ACROSS ILLINOIS/EASTERN MISSOURI AND VICINITY…WHERE LARGE HAIL AND DAMAGING WINDS APPEAR LIKELY ALONG WITH A FEW TORNADOES.” Just like Wednesday, supercell thunderstorms will exist with all the trimmings. Regardless of where you live in the Marginal, Slight, or Enhanced risk area, prepare accordingly for the possibility of all modes of severe weather. Friday could be active as well from Georgia to the DelMarVa region and Saturday in western Texas…but with two rather significant days of severe weather already on our doorstep, we’ll cross those bridges if/when necessary.
Before I wrap this up, I’d like to pass along some helpful information from the Storm Prediction Center. This graphic is an excellent resource and clearly explains the new severe weather risk categories.
- Storm Prediction Center
- National Weather Service
- Tornado Safety
- Flood Safety
- Lightning Safety
- NOAA Weather Radio
- American Red Cross
Let’s meet again tomorrow to take a look at the day’s severe weather setup. It’ll be a much briefer post than this one, and will only focus on tomorrow’s severe weather probabilities. Once again…follow only official National Weather Service sources of watch and warning information along with the broadcast meteorologists of your choice…plan accordingly if you are in a watch…take proper precautions if you are in a warning…and you’ll be just fine. It comes as a surprise to many…but regardless of what these storms throw at you…if you take the necessary safety precautions you’ll come through smelling like a rose.
See you good folks later…