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First off - let me just comment on the Sunday into Tuesday weather. There is debate surrounding the development of a cut off low over the Ohio Valley (cut off lows usually bring lots of clouds and light precipitation with them - cooler temperatures, as well). If this feature forms then there will be a better chance for clouds and possibly rain during the Sunday afternoon into Monday/Tuesday time period. There is basically no model agreement on this feature. Which means there is a lot of uncertainty as to what eventually develops. Something to watch in the coming days.
Below you will see one of the forecast models that I use to make my forecast. The GFS (from www.wright-weather.com). The pink/purple/blue areas are rainfall. You can see the low pressure area over our region and quite a bit of precipitation. IF this verifies then obviously the Sunday into Tuesday official forecast from the NWS (and they have already commented on this subject, as well in their area forecast discussion) will need to be changed. So - if you have weekend plans (especially Sunday) then you might want to check back. Click image for larger view.
Welcome to Fall (which begins later today). We have been in meteorological fall since September 1st (meteorologist consider fall to be from the first of September through the end of November). If you don't have a NOAA Weather Radio then you should get one! Severe weather can occur in our region during every season of the year. Fall and winter is no different. You can click on the NOAA Weather Radio link on my home page - here.
Up to this point, September has behaved just about as forecast. We discussed the potential for above normal temperatures and below normal rainfall - with the wild card being tropical threats. We did receive beneficial rainfall from the remnants of Hermine. Because of this tropical system we added quite a bit of rain to the gauge earlier in the month (over 4 inches here at my location). Otherwise, it has been quite dry across our region.
Temperatures this week have been WELL above normal. I recorded a high temperature of 97 on Tuesday. Almost a record. Quite amazing. Many counties in southern Illinois,southern Indiana, and western Kentucky recorded temperatures in the middle to upper 90s. Unusual to say the least.
Drought conditions continue to spread across more and more territory over the central and eastern United States. The map below shows the September 14, 2010 drought monitor data. The areas in yellow and brown are in need of rain. More information can be viewed at their web-site here. You can also read the drought forecast from NOAA by clicking here.
As we head into the next 6-10 day period it appears that we will experience at least one or two cold fronts and the potential for a cut-off low later this weekend (which would mean some clouds). I am also watching the potential for a tropical storm or hurricane to form in the Caribbean. This system will likely impact portions of Central America and Mexico later this week and weekend and then has the potential to move north into the Gulf of Mexico next week (or a second system could form behind Matthew - some debate on how this plays out). Still some time to watch the formation of this system. You can visit the National Hurricane Center web-site for updated tropical forecasts.
Here are some of the forecast tracks for this future tropical system - assuming it does develop then it will be named Matthew. Forecast tracks below (click for larger image)
One item of note (before we talk about our local weather) - you can see the long range GFS Model (from http://www.wright-weather.com/) bringing a hurricane into the Gulf of Mexico during the first part of October (still plenty of time to keep an eye on this potential system). The data has indicated this for multiple runs (more than 40 runs). So - this is a concern. Keep in mind that this map is a forecast map - this is what one model believes will happen. There are many different models (in other words this isn't written in stone). I believe there could be several tropical systems threaten the United States over the next several weeks (see comments below). Click image for a larger view.
Overall the pattern is shifting towards a greater threat for tropical development in the Caribbean and Gulf of Mexico. Much of this tropical season has developed systems that either pushed out to sea or impacted far southern Texas and Mexico. Several national forecasters have addressed this subject over the last two weeks. Most data indicates that the next 4-6 week period will bring favorable conditions for tropical development anywhere from the eastern part of the Caribbean into and through the Gulf of Mexico. So - an enhanced threat for U.S. impacts. Something to watch.
Back to our local weather...
Today and tomorrow will bring a few scattered showers and thunderstorms (as has been the case the last few days) to our region. Data actually indicates quite a bit of lift around today - especially across then northern half of southeast Missouri and southern Illinois - to help form those showers and storms. Above normal temperatures, as well. You can view your local radar by clicking here.
A cold front will approach and push through our region on Friday and Friday night. A few showers and thunderstorms are expected along the front. Models are not painting much in the way of heavy precipitation. I don't believe everyone will experience rain (about like the last few months - hit and miss). Severe weather threat appears low. This cold front will bring cooler air (relatively speaking) into our region for the weekend. Lower humidity levels, as well. It will at least feel a bit more like fall.
Your seven day forecast can be viewed here - issued by the National Weather Service. Enter your state/city/zip code for your local area. Keep in mind that there is some debate on how the upcoming weekend pans out. So - check back for updates. If this cut off low does develop them we will have to add clouds and precipitation into the forecast - which appears quite likely.
Below are two models that I use (the NAM and the GFS from http://www.wright-weather.com/) - you can see the front by the area of purple on the map. The pink/purple area would be the precipitation totals (blue would be heavier precipitation). Click image for large view (keep in mind that these maps are just showing the Friday event and don't include the potential cut off low later in the weekend)
NAM (above) - one model - light precip painted along the cold front on Friday
GFS (above) - another model of choice. Shows a bit of precip along the cold front (Friday)
There are still some questions as to how the rest of weekend will turn out weather-wise. Quite a bit of data indicates the potential for a cut-off low to develop over the Ohio Valley. If this does form then clouds and rain may need to be introduced into the forecast for Sunday and Monday. For now we will just keep an eye on it. I know there are quite of few outdoor activities this weekend (including the BBQ Festival in Paducah).
Although the last few weeks have brought above normal temperatures - next week should bring temperatures that are closer to normal. The latest official National Weather Service 8-14 day outlook actually indicates that odds favor normal to below normal temperatures. Something we have not seen in quite some time.
Click image for larger view.
8-14 Day Temperature Outlook (blue shaded areas favor below normal temperatures).
Meanwhile the long range temperature maps (from one source - there are multiple sources) still have not changed their tune concerning the coming 4-6 month period. Most data indicates above normal temperatures as we push into the fall and winter months. That does NOT mean we will have a mild winter - it just means that the odds favor above normal temperatures (see my fall forecast for more details). Click maps for larger view (red shaded areas would favor above normal temps and blue would favor below normal temps).
September through November Temperature Outlook (above)
December through February Temperature Outlook (above)
And for those interested in La Nina (Pacific Ocean waters are below normal). The potential is there for a strong La Nina this fall and winter (the current development is amazing - near record drop). The map above shows the dramatic drop in sea surface temperatures. We were in an El Nino pattern - but not any more. The drop below the zero line indicates La Nina. This could have profound implications on our winter weather (see the fall forecast link I posted above).
And finally (are you tired of maps?) here is the latest October outlook from the National Weather Service - it indicates that odds favor above normal temperatures and below normal precipitation.
Temperature forecast map (above) for October (red/orange is above normal temps - odds favor)
October precipitation outlook (above). Brown favors below normal precipitation. Keep in mind the tropical wild cards that I talk about from time to time. If we can bring a tropical storm or hurricane into the Gulf of Mexico then the potential for heavy rainfall events will increase in our region - depending on storm track (same as what happened earlier this month - imagine how dry it would be right now had we not received the remnants of Hermine).
- Beau Dodson
Meteorologist for the McCracken County Office of Emergency Management
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