Wednesday Morning Update

Wednesday, July 25th 2012, 5:31 am
By: Alan Crone

Another hot day is expected but the temperature heat index should stay near or just below 105.  Therefore the official heat advisory will not be in effect today, but in all reality, today will be very similar to yesterday.  We're looking for highs around 100 to 104 with south to southwest winds around 15 to 20 mph with some gusts nearing 30 mph.  The fire danger will again be elevated this afternoon.  Many locations across Eastern OK have county wide burn bans in place, including the Tulsa metro.  

We're still on track for a shot of showers and storms Thursday afternoon and evening into early Friday morning.  There may be a few showers or storms today to our west, but these are not expected to move into our immediate area. The odds of a pop up (isolated) storm in Eastern OK are not zero, but we'll not include the mention on the main 7 day planner for today. 

The mid-level ridge will temporarily give us a break by moving eastward and allowing a northwest flow aloft pattern for a period of approximately 36 hours.  This will occur as a very stout upper level system will slide southeast across the upper Midwest and a mid-level trough moves into the central plains.  This will shove a weak surface boundary southward to near northern OK Thursday afternoon and evening.  It's still unlikely that the real boundary will pass the region Friday, but some of the model data indicates an outflow boundary may slide southward for a few hours into Friday. I'll not make any wind shifts on the map and keep our winds from the south through the period.    

Before the boundary gets close to us Thursday, there is a remote chance that our temperatures will soar well above the forecasted high of 100 Thursday afternoon.  This pattern could easily see our temps go to 100 to 104 with southwest winds and compressional warming. Only the RAW NAM is suggesting this possibility, but past experience indicates this is something we should consider.  An increase of cloud cover, however, may keep us around 99.  I'll bring Thursday up to 100 and we'll see what happens.  

The chance of the storms will increase to almost 50% but I'll keep the chances near 40% which is an increase from yesterday morning's pops.  We have elected to "center up" the pops for the Thursday afternoon-evening time period and not carry Friday midday to afternoon pop for the Tulsa area.  This means the chance will continue into the early Friday morning hours, but for most of the day Friday, the chances for storms will be shifting across southern OK along and south of the I-40 corridor.  Some severe storms will be possible with downbursts of winds possible.  

The front, if it moves south of the Tulsa area Friday, would move back north Saturday as warm air aloft caps the atmosphere.  The mid-level ridge of high pressure at 594DM would also be likely to develop from the weekend into early next week.  EURO data suggest some extremely hot temps at 5K ft. will overspread western OK and western Kansas early next week and grow closer to the Eastern part of the state by midweek.  The temps aloft would easily support some 105 to 108 readings.  The unknown is how any possible precipitation Thursday evening into pre-dawn Friday will counter the rise by inducing the rain footprint across the region.  At this point, we have triple digit weather back this weekend with highs nearing 105 by Monday and Tuesday.

The very latest run of the EURO is now offering a weakness in the ridge on the eastern side for early next week.  This means a chance of showers or storms Sunday through early next week (isolated in nature) across extreme NE OK and NW Arkansas.  I will not include this mention for the morning forecast cycle, but it's something we should monitor. If this scenario pans out, the highs Monday and Tuesday will be down to near 102.  

There is no major relief in sight regarding the significant drought conditions across the state.  The fire danger will continue to increase, despite a small respite Thursday evening into Friday with some showers and storms.  It can be argued that the fire danger will be increasing to dangerous levels by early next week, even if we receive precipitation Thursday into Friday. Some model data is hinting at a pattern change by the beginning of August, but we'll use the "believe it when we see it" method at this point.