7/15 - 7pm CDT - The Heat Returns!

A few showers are ongoing across West Tennnessee right now, but this is quite a bit less than what was expected today. Dry air rotating around a area of high pressure has moved into the region because this high has nudged a bit further westward than originally forecast. This means that a majority of the shower activity has stayed west of the Mississippi River, but a couple thundershowers could still pop up before sunset. These should mostly dissipate before the overnight hours.

Heat and humidity are on their way back as a large ridge of high pressure moves eastward over the next few days. This should surpress storm chances a little bit, but not entirely because temperatures aloft will still be a little cool. This heat at the surface and the slightly cool air aloft should create the typical "summertime pop-up storm" environment that we're used to seeing in the afternoons this time of year. Temperatures underneath this ridge of high pressure should be in the lower to middle 90's in West Tenneessee and middle 90's until Wednesday in Kentuckiana. A front dropping south on Thursday will trigger higher rain chances in both Kentuckiana and West Tenneessee and there could be some slightly cooler temperatures behind the front for Kentuckiana. Things look to remain hot all week long in West Tennessee!

I'm in Jackson, TN right now getting ready for the 10 O'Clock news on WBBJ this evening before going back to Louisville tomorrow. Check out my Hokey Weather Fact from last night's show on the left and be sure to tune in to WBBJ tonight at 10 for a new one!

 

7/16 - 11am - Heat Building Back In

Ridge over Central US on Wednesday

It's been cooler and quiet over the past couple of days in Louisville with temperatures around and just below 90. That's going to change fast though as a hot and dry upper-level ridge begins to build into the eastern half of the nation next week. Today and tomorrow don't look particularly bad with temperatures in the low 90's and a slight chance of some afternoon pop-up thunderstorms

Thursday Eve. temperatures (GFS)

By Monday we'll be talking temperatures in the mid 90's and not a chance of rain in sight. The warming temperatures aloft with this ridge will limit instability for thunderstorm development significantly. Surface features like fronts will also be very hard to come by once this thing moves over us, so there won't be a trigger for storms either. What this means is that while the heat is building in we won't have any relief via the normal summertime afternoon storms that form. The compounding of the heat and dry air over the course of next week could send our temperatures to the 100 degree mark for the first time this season. Humidity-wise next week won't be as bad as it was earlier this week with dew points exceeding 80 degrees, but dew points in the mid 70's, still very humid, are possible especially on Tuesday and Wednesday. Below is some raw data from the GFS MOS output, which is basically a combination of numerical and statistical weather models. This output usually runs a  degree or two on the warm side this time of year, but I've highlighted the warmest temperatures of the week in red and highest dew points in green:

GFSX MOS (MEX)
 KSDF   GFSX MOS GUIDANCE   7/16/2011  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|
 SAT  16| SUN 17| MON 18| TUE 19| WED 20| THU 21| FRI 22|
 X/N  89| 73  93| 75  95| 78  96| 79  98| 78  99| 78  97|
 TMP  85| 75  88| 77  90| 80  91| 81  92| 80  93| 80  91|
 DPT  69| 70  69| 72  70| 75  74| 75  72| 72  71| 71  70| 
 CLD  PC| PC  PC| CL  PC| PC  PC| PC  PC| PC  PC| PC  PC| 
 WND   6|  6   7|  6   9|  9   9|  9   8|  7   8|  7   8|
 P12  24| 13  14|  7   9| 19  40| 27  20| 12  25| 14  19|
 P24    |     19|      9|     40|     40|     25|     34|
 Q12   0|  0   0|  0   0|  0   1|  0   0|  0   0|  0    |
 Q24    |      0|      0|      1|      1|      0|       |
 T12  26|  8  32| 10  24| 37  49| 49  39| 29  28| 21  36|
 T24    | 30    | 40    | 50    | 71    | 49    | 44    |

Looks pretty hot doesn't it? A span of three or more 90 degree plus days is usually considered a heat wave, so I think we'll meet and exceed that definition easily. Next week will be a good time to take it easy and drink lots of fluids when working or playing outside. Here comes the heat!