Roller Coaster Ride Weather the Next Few Days -- March 1, 2015

IN REVIEW: Quite the difference in weather across the area yesterday. A snow storm did effect northern parts of our region Saturday into Sunday, just in case you didn't notice. It was a very sharp cutoff with totals; as much as 9" fell in Palestine, IL in Crawford County while most of the Lower Ohio Valley received NOTHING. The cutoff line was approximately located from near Mcleansboro, IL northeast to Vincennes, IN. Anything south of there received nothing -- just a few light rain/freezing rain showers. Stubborn dry air held over much of the area in the nighttime hours of Saturday limiting precipitation; including my location in Warrick County. Our counties were on the southern edge of a larger snow storm; St. Louis and Indianapolis received a decent amount of snow out of this as well. 

WHAT'S AHEAD: The next few days will be a wild ride weather wise. Tomorrow, though cold, won't be that crazy compared to what is forecast for the two days following. Highs temperatures will range from near 32F in northern areas where the snow pack resides to lower 40s across the southern tip of Illinois into Western Kentucky. Still won't see much sun. Frown.

--TUESDAY--

Precipitation will break out early Tuesday morning mainly in the form of rain; though a brief period of freezing rain is possible with this right as the precipitation starts especially across our northern tier. By the middle of the day Tuesday, all areas across our region will make the transition to rain as southwesterly winds will pick up. The rain could become heavy at times, especially across southeastern parts. Totals could end up over 2" southeast of a line from Paducah to Owensboro. I think widespread totals of an 1" or so is likely. There is some elevated instability with this, so a few thunderstorms are possible. High temperatures Tuesday afternoon will be a welcome site for most folks. Mid 40s across the far north to near 60F in the Bowling Green, KY area. However, the mild temperatures won't last for long. The front, instigated the precipitation, will begin to stall southeast of the area as we head into Wednesday. This is where the potential fun will begin with wintry precipitation.

--WEDNESDAY--

Where the front stalls and the resulting thermal profiles will make difference as to where the wintry precip will setup and what type of precipitation you will receive. All of the numerical models show a secondary wave of low pressure riding the front Wednesday, so confidence is fairly high that a winter weather event will occur SOMEWHERE in the region. The data tonight continues that trend. The GFS is the only model that shows a suppressed solution that would limit any wintry mischief to our far southern counties. The rest of the guidance shows a more widespread wintry scenario. A lot goes with this forecast:

1.) The Arctic High: The delivery mechanism of the cold air, the strength and position of which will affect precipitation potential. *The GFS is a bit stronger, further east. Suppression would occur for most of the area.*

2.) Stalling Frontal Boundary: Where exactly does it stall out? All data shows southeast of us. Location is critical to the track of the wave and our temperatures. *GFS a little further southeast than other guidance.

Then the story after the potential wintry weather will be the cold. Highs Thursday will stay in the 20s, perhaps lower 20s for areas with a decent snow cover. Overnight lows would then drop accordingly into the single digits for those areas. Ouch.

Warmer weather (above freezing) would probably return by Friday. It is March after all.

ADDITIONAL NOTES:
Most of the remaining snow pack from the Feb. 16-17 storm has melted. This ends a streak of about two weeks (Feb. 17-Mar. 1) where at least 1" of snow has been on the ground. While not unprecedented, a snow depth of 1" for that long is something that doesn't happen quite that often at this low of a latitude. 

The snow that fell with the Feb. 21-22 storm has remained in our northern counties, and with the new snow of 5-8" that fell yesterday, folks have a decent snowpack up there in excess of 9". A lot of melting will occur Tuesday, however, as temperatures will rise at least in the lower 40s and rain falls. Wouldn't be surprised for a bit of flooding in remaining snow-ridden areas as rapid snow melt and falling rain will create lots of water.
-------------------------------------------------------------------------------------------------

Note: No images in today's blog (makes it kind of boring). Future posts will have images of maps, guidance, weather pictures, etc. Just couldn't get them tonight. 

Thanks for reading!

The Weather Week Ahead: September 7, 2014

TODAY: Today's weather was absolutely amazing with a crystal clear cobalt blue sky all day and a nice northerly wind fetching in low dewpoints and pleasant temperatures. Highs across the area ranged from the upper 70s to low 80s, with comfortable dewpoints everywhere in the 55-60F range.

LOOKING AHEAD: Yes, tomorrow will be pretty much the exact same as today: sunny and nice, but actually the morning will be a bit cooler. Expecting low temperatures for tomorrow morning to be in the lower 50s. Highs may top out a little warmer than today, but still nice. Lower 80s. Tuesday looks to be a day of change. After another cool morning starting in the lower 50s areawide, southerly winds will take over in the afternoon as our next storm system takes shape to our west. It will be more humid Tuesday afternoon as dewpoint values rise, with high temperatures in the upper 80s to near 90F. Tuesday night will be warm, 68-72F, setting the stage for a potential convectively active day for the region Wednesday. Cyclogenesis will take place across the plains Tuesday, and the area of low pressure will deepen as it moves east into the Great Lakes Tuesday night into Wednesday to under 1000mb. Attached to this low will be a strong cold front, associated with it the chance of severe weather. Convection will likely be ongoing Wednesday during the day for areas northwest of the Lower Ohio Valley, but this activity will stay north and west probably through the day with our greatest chance of storms coming in the evening hours. The 18z run of the GFS initalizes convection to our west by the mid afternoon, with northwestern parts of our region being affected by the late afternoon. This line will be pressing southeast across the area Wednesday evening, and the threat could remain until the early morning hours of Thursday. The numerical models are all showing this line weakening by the early morning hours as dynamic & diurnal support weakens, with different ideas as to the location of where the storms will weaken. This will come into better focus for the next few days. I think the main threat with this system will be damaging straight line winds, a low hail and tornado threat exists for now. For our area, I think the areas with the most likely chance to have any sort of severe weather will be across Southeast Illinois, with gradual lower chances of severe to the east of there across Southwest Indiana and Western Kentucky.

FALL ARRIVES: Behind the cold front, the October-like airmass will rush in, as a 1030mb surface high glides across the Great Lakes. Thursday, Friday, and the weekend will feature highs ranging from the upper 60s to the mid 70s. Not to mention, low temperatures will be crisp. Looking at the potential for upper 40s for low temps next weekend, with lower 50s a sure guarantee. Sunny skies will prevail for Thursday through Saturday, turning mostly cloudy though as an upper disturbance moves along Sunday associated with it a chance of light rain. All in all though, it will be delightful.

CLIMATE: 80F was the high temperature today at 2:49 PM. The low, thus far today, has been 59F at 5:51 AM. The normal high temperature for this date at Evansville is 85F, while the average low for September 7 is 61F. The record high for today is a sultry 101F, set in 1925, while the record low temperature for this date is 43F, set in 1988. Today we received 0.00" precipitation. The record daily amount for today is 1.49", set 100 years ago in 1914. Through September 7, Evansville has received 1.11" of rain, 0.44" above the normal through this date of 0.67". For the year, Evansville has received 35.29" of precipitation, above normal by 3.70". Through September 6, temperatures for the month have been running warmer than normal, with an average temperature so far this month being 77.5F, 3.8F above.

--------------------------------------------------------------------------------------------------------

Thanks for reading!

July 14, 2014: BIG Cool Down Coming

TODAY'S WEATHER: A few spots across the area, mostly across northern areas of southern IL, had to deal with some severe weather today in association with the secondary and "main" cold front. There was a severe thunderstorm watch posted for areas north of US-50 in IL and IN this afternoon, where a few severe thunderstorm warnings were issued. The Lawrenceville Airport in Lawrence County, IL recorded a 63mph wind gust as the storms blew threw there. Most of the region, though, was spared from the severe weather just dealing with some showers. Temperatures weren't terrible but the humidity was there this afternoon. Highs today ranged from the mid to upper 80s across the Lower Ohio Valley, with a 86F at EVV, an 87F at LOU, and the warm spot of 89F at PAH.

COOL DOWN COMING: Yes, a very nice cool down is coming. It will feel more like September or even early October as an anomalous upper low and trough dig in over the Eastern US. Starting tomorrow morning you'll feel it. It will be in the lower 60s to start tomorrow, with afternoon highs ranging from 72F-76F across the region. Of course dewpoints will be dry probably dipping down to near 50F by tomorrow afternoon. It's going to be a gorgeous day no matter where you head.

18z GFS 500mb level valid 4pm tomorrow - shows the upper low centered on top Lake Huron

Great looking surface map as well with a nice northerly wind w/ surface high pressure to our west as CAA takes place - GFS valid 4p tomorrow

Tomorrow night is going to be a very cool morning, getting pretty close to record territory. Lows will range from 52-56F areawide. The record Wednesday morning at Paducah is 56F set in 1967, record at Evansville is a tough to beat 47F set in 1930, and for the Louisville area it is 55F. We will be close to records in some areas. Wednesday will be about the same as Tuesday - mix of sun and cumulus clouds and perhaps a touch warmer. Highs 75-79F. Just great. Wednesday night cool again, with low temps 54-58F. The low humidity and comfortable will continue AGAIN for Thursday, as general "trougheness" will remain. Highs a touch warmer again, but still very nice 77-81F. Slight chance of rain will exist Friday for areas in KY, but shouldn't be a big deal as the mid level wave instigating the precipiation should steer south enough to be a nuisance. There will be more clouds around during the day Friday due to the increased moisture associated with the mid level shortwave, but the temperatures will once again be comfortable in the mid to upper 70s for highs.

To wrap things up, I wanted to show you a graphic showing how far south this cool air outbreak will stretch. Take a look at this map showing surface temperatures across the southern half of the US. Look at far south the closest 80F contour is. It's well down into Arkansas and Tennessee! And the closest 90F? Way down on the Gulf Coast!

18z GFS valid 4p tomorrow - 2m temperatures. 70s for highs as far south as Tennessee & Arkansas.

Get out and enjoy this cool spell! I think the humidity will become noticeable again by Saturday, but certainly 5 days of low humidity and comfortable temps is welcome as it's a rarity here in mid-July. Thanks for reading!

July 12, 2014: Look at the Severe Risk for Tomorrow

TODAY'S WEATHER: A few showers/storms late this morning and into the early afternoon today gave way to a pretty nice day, albeit humid. The high made it to 85F at EVV this afternoon, after 0.26" of rain was recorded with the convection earlier in the day. The low this morning was a muggy 72F.

SEVERE WEATHER OUTLINE: The real purpose of this post, though, is to outline the severe risk for tomorrow evening. The Storm Prediction Center has placed the entire Lower Ohio Valley under a slight risk for severe thunderstorms tomorrow afternoon and evening:

SPC Convective Outlook for Tomorrow, July 13

The threat is associated with a cold front that will dive across the Great Lakes into the Ohio Valley tomorrow. Forecasting the convection to fire well north of the Ohio River by 4 PM tomorrow, and gradually push southeast across the region heading into the evening hours. Here is the simulated radar reflectivity from the 12z NAM 4KM for tomorrow, valid at 7 PM CDT:

NAM 4KM shows convection south of the Ohio River by 7 PM.

With CAPE values expected to exceed 2,000 J/KG tomorrow afternoon, along with effective bulk shear values above 30kts, the storms should have no problem organizing into bowing line segments. Damaging wind is the main threat with these storms tomorrow, along with a chance of a tornado. The large hail risk is lower than previous events as the freezing level is well above the surface, in the 600mb range. Of course the hail potential is still there, but it will have to fall through a decent layer of above freezing air before reaching the surface.

Another threat for tomorrow is the heavy rainfall. The heavy rain threat is elevated for tomorrow greater than it normally would because of PWAT values approaching if not exceeding 2" just ahead of the boundary (basically, the atmosphere's ability to "ring" out the moisture available through all levels). Precipitable water values over 2" mean that the atmosphere is LOADED with moisture. Flash flooding is a big concern. Here is the projected PWAT values for tomorrow evening coming from the 18z run of the NAM:

Greatest precipitable water values (in excess of 2") across Southern IL into Southwest IN at 7 PM, according to the NAM.

REFRESHING air will be the story heading into midweek. I'll have details on that coming up after this severe weather. Follow @wxSam on Twitter for realtime updates tomorrow.

The Outlook: June 18, 2014

LOCAL WEATHER: It was once again a hot, humid day across the Lower Ohio Valley. The temperature reached 94F at EVV this afternoon, 93F at PAH. Besides the heat, we have had a few isolated storms pop up today. There was actually some strong thunderstorms in Southwest IN this afternoon; namely in parts of Gibson, Daviess, Pike, Knox, and Martin counties. These did produce heavy rainfall but they were not severe. The severe weather has been confined to areas east of the area; where severe t'storm watch #326 is in effect from the Southeastern part of Indiana up through Western Pennsylvania. Tonight, we could deal with some of the remants of some strong storms presently in Northern IL, but they are expected to be no more than showers by the time they reach northern stretches of our region. Low tonight near 74F. Another hot one for tomorrow. High temperature near 92F with a mix of sun and cumulus clouds. The chance for a thunderstorm during the afternoon remains, but they will still be isolated in nature. Friday the coverage of showers and thunderstorms look to increase. After another very warm start, near 75F, some convection could be in the area as soon as the morning hours as some of the models advertise. The coverage of the storms will grow as we head into the afternoon Friday as a weak boundary approaches from the northwest. Some of the storms could be strong; but an organized severe threat isn't expected. High temperatures on Friday a touch cooler, near 88F but it will remain humid. Friday night looks like a gradual drying trend. Lows a little cooler (still warm), near 70F. Saturday looks to remain warm and humid as the tropical airmass remains in place; highs near 90F with a mix of sun and clouds. There is a a a bit of model discrepancy for whether showers/storms will be in the area on Saturday. I'm going to cite with the drier NAM solution, but going to leave a 10% chance of a storm just in case. The upper ridge looks to break down and lose its place as a domiant weather factor in the coming days.

TROPICAL ATLANTIC: No tropical cyclone formation expected in the next 48 hours.

THE EAST PAC: The NHC has removed the invest area that they previously had south of the Pacific Mexican Coast. Shower and thunderstorm has become too disorganized for any tropical cyclone development in the near term.

CLIMATE EVV:
For yesterday - June 17, 2014:
High 92F Low 75F Avg 84F
Precipitation: 0.00"
Normals for June 17
High 86F Low 65F Avg 75F
Records for June 17
High 100F (1918, 1936) Low 50F (1961)

Since June 1 Precipitation: 2.56" (0.26" above normal)

The Outlook: June 17, 2014

LOCAL WEATHER: Just like yesterday, it is hot and it is humid. The temperature at EVV at 3 PM was 91F, a dewpoint of 69F, and there is a southwest wind present at 14 MPH. We have a mix of sun and clouds, with more sun north. There are a few returns on radar, as a few popup showers (really just sprinkles) are around. If you get under one of these, it will not last long - maybe a minute or two today. Temperatures through the evening will fall through the 80s to a rather warm overnight low near 73F. Tomorrow looks about the same as the past few - a mix of sun and clouds with SW breezes with a humid high near 92F. Could see a pop up shower tomorrow as in the summer you can rarely say there's a 0% chance of rain because of the buoyant nature of summer air masses even though there is no "real" forcing mechanism and that there is still an upper high over the region, but they will be isolated. Tomorrow night looks dry with another very warm overnight low near 74F. Really looks about the same for Thursday as well. High temperatures near 92F, with a mix of sun and clouds with a slight (20%) chance of a shower/storm. Broken record. Perhaps on Friday the coverage of the showers/storms will be slightly greater, as the upper high gets beaten down somewhat. 30% chance, so still not very high but it's higher. Highs on Friday near 91F with partly sunny skies. It's going to remain a pretty boring weather pattern through the end of the week.

TROPICAL ATLANTIC: No tropical cyclone formation is expected over the next 48 hours.

THE EAST PAC: The NHC continues to outline an invest area with a tropical wave well south of Mexico. The showers and storms associated remain disorganized, and thus the NHC has given the wave a 30% chance of tropical formation in the next 5 days.

The Outlook: June 15, 2014

LOCAL WEATHER: Well, the heat and humidity has come as promised. The temperature at EVV at 4 PM was 87F, a muggy dewpoint of 66F, and a wind out of the south at 16 MPH. We have had some shower activity over Southern IL, but it has diminished for now. We have reached our high for the day, and we'll slowly fall through the 80s this evening to a overnight low much warmer than previous mornings, near 71F. The SPC has actually outlined areas northwest of Evansville in Southern IL under a slight risk for severe weather through this evening. The latest HRRR model does fire some more convection today, initating it pretty much along the Mississippi River this evening. We'll see if this plays out. If it does, then there could be a severe t'storm watch issued this evening and some reports of severe weather across Southern IL. I don't it'll make it into Southwest IN or Northwest KY at severe criteria, but we could deal with the remant showers/generic thunderstorms. Tomorrow, with the weak boundary in the area, a few more showers/storms could fire. Sticking with that 40% chance. The sky will be partly cloudy tomorrow, with an afternoon high near 90F. Our first official 90 degree day for the year. Monday night looks dry, low near 71F. The day Tuesday looks dry and hot. The high temperature will be even warmer than Monday, with an afternoon high near 92F. The sky will be mostly sunny, with the muggy dewpoints sticking around - upper 60s. Really nice. Wednesday looks about the same. After a warm start near 70F, the afternoon high will be near 92F. The GFS does fire a few storms during the day, but with the upper high firmly in place across the region I won't put it in the forecast for now. The hot, humid, sunny weather will continue on Wednesday.

TROPICAL ATLANTIC: There is no tropical cyclone formation expected over the next 48 hours.

THE EAST PAC: The last advisory has been issued on Cristina. It is now a 35 MPH post-tropical cyclone, with a low central pressure of 1005 MB. It will be pretty much off the radar screen by Monday. Besides Cristina, the NHC has outlined an invest area a few hundred miles south of Guatemala. The NHC has a 10% chance of this thing developing into a tropical cyclone over the next 48 hours, with a medium 30% chance of development in the next 5 days. The area of disorganized t'storms now is expected to get more organized in upcoming days as the environment is favorable west of the system. We'll keep an eye on it.