When you hear that high pressure is moving into the area, you usually expect fair weather and clear skies. Most of the time that is the case, but every now and then we get what’s called a “dirty high” pressure. This typically happens when a cool high pressure system moves over saturated land.
SURFACE MAP (MONDAY 4PM)
CLOUD FORECAST (MONDAY 4PM)
BLOG ENTRY BY: PATRICK CRAWFORD (6:16 AM)
Rainfall totals were the highest across the southern part of our viewing area. Below are a few totals from Independence day.
Now the story is the cool weather that is moving into the area. Some locations didn’t even reach 80 degree this afternoon. Here are a couple cool weather statistics while they last. Temperatures will soar by late this coming week.
Ross Ellet
The morning storms have helped to stabilize our atmosphere. It has also pushed the outflow boundary much further to the south this afternoon. As a result the severe weather potential will stay low across the river valley and very low in northwest Arkansas. More storms could develop across the river valley later tonight and train through the area which could lead to heavy rainfall and perhaps some gusty winds. However these will remain the biggest threats. As for the fireworks forecast…it is tricky. At this time it appears that northwest Arkansas will stay mostly dry, however scattered thunderstorms will continue across the river valley. Many fireworks displays will likely be able to get off the ground between storms, however it will be a wait and see situation. Here is the NAM computer model showing tonight’s storms. The first image is showing the accumulated rainfall before 7pm.
The second image is showing the accumulated rainfall between 7pm and 1am tonight.
Ross Ellet
Big forecast changes have occurred since yesterday. The cold front that was advertised to spark off showers and storms during the evening has moved further south. Showers and storms have already developed this morning across NE OK and NW AR.
Look for showers and storms throughout northwest Arkansas during the rest of the afternoon. The severe weather threat will be low; however, locally heavy rainfall may become an issue. Expect .25″ to 1.00″ of rain. By this evening the rain should be moving out, so hopefully the fireworks will be ok.
The River Valley and south is a different story. Showers and storms will have a better chance of becomingstrong to severe during the afternoon along I-40 and south with an increase amount of instability. Numerous outflow boundaries will serve as a focus for showers and storms this afternoon. CAPE values have already jumped to near 3,000 J/KG across SE OK.
Large hail and gusty winds are the primary threats. Fireworks displays may be in jeopardy with the scattered nature of the storms.
Drew Michaels
The rain that fell this morning broke a two and a half week dry spell across northwest Arkansas. The river valley will have to wait another day to get the much needed rain. The showers and storms were scattered with locally heavy rainfall. The southern part of Fayetteville (at the airport) only picked up 0.16″ while an observer 1 mile east of Fayetteville picked up 0.79″.
Ross Ellet
Most of the showers and storms are starting to clear out. We will continue to see a few showers in Benton County for the next couple of hours, but most of the viewing area will see some dry weather. The latest visible is showing a big clearing off to the West. This clearing has already started to move into parts of Eastern Oklahoma. Everyone should start to see some sunshine this afternoon and then quiet weather arrives for tonight.
VISIBLE SATTELITE IMAGE
BLOG ENTRY BY PATRICK CRAWFORD (7-3 9:25 AM)
Where is all the rain you may ask? Try the desert. An upper level ridge has continued to keep us baking while the “ring of fire” (storms on the outer edge of the upper level ridge has continued to stay in the west and upper Midwest. That favorable flow has allowed the annually Arizona Monsoon season to begin (also known as Southwest Monsoon, or Mexican Monsoon) a couple weeks early. A monsoon is defined as a seasonal shift in the average wind direction. During the Arizona Monsoon converging winds draw moisture from both Baja California and the Gulf of Mexico into the desert southwest. This moisture along with the strong daytime heating often leads to afternoon and evening thunderstorms.
This process has begun and acording to climate experts this may be a very strong monsoon season across the southwest including above normal rainfall which often leads to flash flooding. If this pattern does continue it may mean more heat and dry weather over the next couple of months for us here at home. This is assuming the upper level ridge continues to hold in place. For more information on the Arizona Monsoon you can click on the link below:
http://www.wrh.noaa.gov/twc/monsoon/2009monsoon_outlook.php
Below are today’s satellite images showing the monsoon flow.
Ross Ellet
The heavy spring rains in late April and early May was to much and to early in the season. The rains that fell 2 months ago are proving to be a weak match to the extended hot and dry period as of late. The U.S. Drought Monitor has now issued a D1 drought ”Moderate Drought” area across central Oklahoma and a D0 “abnormally dry” area has been issued for all of northeast Oklahoma and western Benton and Washington counties in Arkansas. Here are the Oklahoma statistics.
Most of the area has now gone through between 16 to 18 consecutive dry days. This along with the extended forecast is not to encouraging. Here is the 8 to 14 day outlook which shows the conditions for mid July. The result is a similar pattern, hot and dry. The following image is a drought outlook which shows drought conditions continuing or even getting worse over the following several months.
Ross Ellet
Now that we are getting closer to the weekend the forecast models are starting to show consistency. The latest outlook from the storm prediction center is showing a slight severe weather risk Saturday and Sunday. The latest weather models are indicating our severe storm chances late Saturday and early Sunday morning.
SEVERE WEATHER RISK (7AM SATURDAY – 7AM SUNDAY)
SURFACE MAP (SUNDAY MORNING)
A cold front moving in from the Northwest will be responsible for our storm chances and the timing of this front will determine when our storms will fire up. Right now, the best chance for storms will be Saturday night and Sunday morning. Here is a look at the latest precipitation forecast.
PRECIPITATION FORECAST (SUNDAY 1AM)
The main weather threat with these storms will be isolated damaging winds and large hail. Keep on checking the 4029 tv weather blog for all the latest updates. Also, don’t forget…you can follow the 4029 Super Doppler Storm Team on Twitter! www.twitter.com/4029weather
BLOG ENTRY BY: PATRICK CRAWFORD (7/2 4:10AM)
I’m sure you have enjoyed the lower humidity this afternoon. We’re sitting in a great spot between an area of low pressure to the east, and a dominant high across the southwest.
The low across the northeast is responsible for the lower humidity. Air around the low flows counter clockwise, and that’s why our winds have been more northerly. That northerly wind has helped to usher in dry air from the north.
Unfortunately, this pattern won’t last, and the heat and humidity will push back in from the southwest for Friday and Saturday. Enjoy this airmass while we have it!
Drew Michaels
