Wednesday, April 22, 2009
Green or Global?
Closed low moves out
A much better looking weather picture for the next several days. We have been dealing with a couple of anomalies which keep clouds and showers around for quite a while. First let's talk about a closed low or cut off low. Here is the definition from the National Weather Service:
- Cutoff Low
- A closed low which has become completely displaced (cut off) from basic westerly current, and moves independently of that current. Cutoff lows may remain nearly stationary for days, or on occasion may move westward opposite to the prevailing flow aloft (i.e., retrogression).
"Cutoff low" and "closed low" often are used interchangeably to describe low pressure centers aloft. However, not all closed lows are completely removed from the influence of the basic westerlies. Therefore, the recommended usage of the terms is to reserve the use of "cutoff low" only to those closed lows which clearly are detached completely from the westerlies.
Tuesday, April 21, 2009
Monday, April 20, 2009
Temperatures Tumble to Begin Week
A very chilly start to the day but southwest winds are going to bring in some warmer air with highs moving into the 50s. But the biggest problem for the next two days is going to be the rain. Showers will continue to be pushed northward by stubborn low pressure which will move gradually to the east over the next 36 to 48 hours. Most of the next two day will be kept in the clouds as well.
You can see the low parked across the area and that's the main factor for today and tomorrow. You can also see the QPF which is bringing in about another .50 to 75" of rainfall through Tuesday afternoon.
Thursday, April 16, 2009
You can see on this surface map that there is a lot going on around us. Low pressure to our west and east, but finally some high pressure blocking any cloud cover and changing very little over the next 3 days. That's about all you can hope for right now as we have a very fast moving jet stream. Okay, so I know this is going to be a little mind expanding and I apologize for it in advance, but I wanted to show you the 200 mb chart. This is the place where the jet stream resides. You can see by the legend that we do have 100 knot winds pushing weather systems through very quickly. Right now that jet is driving the fastest moving air to the north. High pressure is also a factor in pushing this jet stream north. There's always been a debate in meteorology on whether the jet stream steers high and low pressure or low and high pressure steer the jet stream.
Wednesday, April 15, 2009
A bit better today
Tuesday, April 14, 2009
Another day of clouds and showers
After this weather system passes warmer temperatures are on the way. In fact, we could see highs top out in the upper 60s through the end of the week. Sunday and Monday look like a very different story.
Sunday another wave of low pressure comes in from the south. While it looks like warm air advection in front of this system it's another story by Monday morning.
You can see 850 mb temperatures drop into -6 to -10. That's moderately colder air for this time of year and we'll have to watch to see if this moderates at all over the next couple of days.
Monday, April 13, 2009
It's Back
I'm a little concern with the QPF map putting a 'bulls eye' right across the northern part of the state. It has 1.30" of rain. That's not good news as the ground is still saturated from the six plus inches we've had in the last 20 days.
Here is the surface analysis for today. You can see that low pressure is being forced north by a fast moving jet stream. This strong jet stream is left over from our cold winter and is going to be a factor through the early part of the spring and may linger into early summer. Because of these factors we could see some violent spring weather across the south. Don't be surprised to hear about more tornadoes across the south today and tomorrow.
Here is the jet stream pattern for this week. For today you can see there is a real dip across the central part of the U.S. This is being caused by low pressure which will bring quite a bit of instability to what we traditionally call 'tornado alley' later today.
For us, I think heavy rain is about as severe as it will get around here. You can see the jet stream improving and moving north later in the week. That will be the return of high pressure which will greet us with sunshine after tomorrow.
Thursday, February 19, 2009
Friday, February 6, 2009
NOAA Unveils New Alert System for La Niña and El Niño
La Niña Likely to Continue into Spring
February 5, 2009
Pacific Sea Surface Temperature Animation (Nov. 12, 2008 to Jan. 28, 2009).
High resolution (Credit: NOAA)
NOAA’s Climate Prediction Center today issued the first La Niña advisory under its new El Niño Southern Oscillation (ENSO) Alert System. Forecasters expect La Niña to influence weather patterns across the United States during the remainder of the winter and into the early spring.
Defined as cooler than normal sea surface temperatures in the central and eastern equatorial Pacific Ocean, La Niña impacts the weather globally. La Niña’s opposite is El Niño, or warmer than normal ocean temperatures. These changes in ocean temperatures alter the tropical wind and rainfall patterns with far reaching implications.
“The typical weather patterns associated with La Niña and El Niño affect many industries including agriculture, transportation, energy, shipping and construction,” said Michael S. Halpert, deputy director of the Climate Prediction Center. “The ENSO Alert System will succinctly inform industry, government agencies, academia and the public about the onset and status of La Niña and El Niño. This system will also help decision makers plan for the potential effects presented by these conditions.”
La Niña conditions have been present since late December, but it is too early to say exactly how strong the event will be and precisely how long it will last. However, for the next few months La Niña is expected to bring milder and drier than average conditions to the southeastern and southwestern states. It is also expected to bring wetter-than-average conditions to the Ohio and Tennessee valleys, and cooler than average temperatures to the Pacific Northwest.
The new ENSO alert system includes La Niña and El Niño watches and advisories which the Climate Prediction Center will issue when specific conditions exist.
- La Niña or El Niño Watch: conditions in the equatorial Pacific are favorable for the development of La Niña or El Niño conditions in the next three months.
- La Niña or El Niño Advisory: La Niña or El Niño conditions have developed and are expected to continue.
These watches and advisories are now part of the ENSO Diagnostic Discussion, which is issued by the Climate Prediction Center on the Thursday falling between the 5th and 11th of every month. It is available online.
NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.Friday, January 30, 2009
Ice Storm Pictures
Wednesday, January 28, 2009
Tuesday, January 27, 2009
You can see in the 48 hour 850 mb plot that the low which will be responsible for this storm is well across the Northeast. I don't believe it travels far enough to the north and east for us to get into the heaviest snowfall. In fact, I put it on more of a Cincy to Buffalo track. This would bring snowfall in but would relegate the heaviest snowfall south of Fort Wayne. Maybe Bluffton on south ward may get 4 inches of snow. South of that especially in the Muncie are we could be looking at about 6"
Here is one of the models we use here at the weather center it's called Addonis and we call it Futurecast on TV. It shows the low across southern Kentucky. More importantly it takes it on a southward track.
Take a look at this snap shot early Wednesday morning. The track takes it south of Columbus, Ohio. That would put the heaviest snowfall south of our area.
Cold air will be back after that through Friday morning as 850 Celisus temperatures drop to around -12 degrees.
Thursday, January 22, 2009
You can actually see the mild air coming for a visit today with 850 mb temperatures near +3! Okay, so here's the other shoe...and it's big one. This usually happens ahead of an arctic weather system as that gateway to the north will be opened by another 'clipper' type weather system moves through the area and changes the flow to a north flow which opens up that arctic gateway.
You can see the cusp of the cold air moving in late Friday behind the clipper system with temperatures of -14 to -22 Celsius coming into northern Indiana by Friday evening.
It's not the core of the coldest air but it is certainly formidable as the coldest air (-50 C) sits in southern Canada and northern Michigan. But a couple of things really don't bode well for a quick moderation in temperatures. One is that the cold air is moving across an area which snow covers the ground. That makes it nearly impossible to moderate temperatures. The other is that the core of cold air is not far from the air mass we will be experiencing.
Monday, January 19, 2009
You can still see the arctic still opened up through Tuesday morning. That gateway will allow for another cold day Tuesday as well.
Mid-Week Warm up:
On Thursday morning you can see the cold air retreat up towards northern Canada. The gate way closes a bit with warmer air coming in. The core of the coldest air is back in the polar regions of the world.
Another Shot of Cold Air: It doesn't last though with another 'clipper' system coming in on Friday with snow chances and especially more cold air. You can see the low the moves across Ohio and to the east coast.
The core of the coldest air comes down from the north again to southern Canada. This is a little troubling as we will see cold air through the weekend. Not as cold as last week but still very cold. A word of caution here, this is the only model carrying the cold air. As usual we'll wait for the other models to come around to this solution.
Thursday, January 15, 2009
Wind Chills
Wind chill temperature = 35.74 + 0.6215T - 35.75V (**0.16) + 0.4275TV(**0.16)
In the formula, V is in the wind speed in statute miles per hour, and T is the temperature in degrees Fahrenheit.
Note: In the formula, ** means the following term is an exponent (i.e. 10**(0.5 ) means 10 to the 0.5 power, or the square root of V), - means to subtract, + means to add. A letter next to a number means to multiply that quantity represented by the letter by the number. The standard rules of algebra apply.
For reference, the old wind chill formula was:
T(wc) = 0.0817(3.71V**0.5 + 5.81 -0.25V)(T - 91.4) + 91.4
Source for both formulas: The National Weather ServiceBy the way wind chill only applies to people and animals not objects.
Wednesday, January 14, 2009
Can it be too cold for snow? Nope it can snow at any temperature. As the temperature gets colder the snow grain gets smaller because the colder the air is the less moisture the air can hold.
It stays cold: You can see this red color on this 850 mb map. It depicts -26 Celsius. That's bitter cold.
The cold air stays in place through Saturday. Here's Saturday morning with 850 mb temperatures still -26 Celsius.
Tuesday, January 13, 2009
Watchs warnings all dropped
I know I have simplified this a little but the NWS does coordinate with other offices and sometimes they don't like the warnings either but you can have single counties in one region with warnings and when counties that connect to them don't have warnings. I understand the dilemma but it doesn't mean I like it. I guess we can chalk it up to the government and as you know nothing gets done easily or for that matter seamlessly by the Feds. Okay my rant is over. For a full discussion of today's forecast check below.
I know this surface analysis is a little messy but bare with me here. The isobars on the map are tightly packed with means some gusty winds on what we call a tight pressure gradient. That means the pressure is going to be changing. You will see barometric pressure of 30.30" and higher because cold air is very heavy.
It's here to stay: Bitter cold air will stick around.
Not only will the bitter cold air stick around it looks like another couple shots of snow as well. It's still cold with -16 Celsius temperatures at 850 mph by Saturday. It looks like cold air is not the only story. Another weather system will come in late Saturday and into Sunday.
You can see this system here as it will bring another chance of accumulating snow on Sunday.
Sunday, January 11, 2009
Friday, January 9, 2009
Here is what the general consensus of models and thinking is right now. The heaviest snowfall band should be across extreme northern Indiana over the next 24 hours.
Here's the interesting part, the track of the low pressure with the low tracking right through Lafayette and just south of Fort Wayne. This track is troubling since it puts the heavy snowfall north of the area. I believe that's why NWS has put most of it's emphasis for the 'winter storm warning' north of Fort Wayne.
Here is the position of the low by Sunday afternoon so you can see the northward track this system is taking.
Then it's just plain ol' cold: I won't spend a lot of time on this right now as we are dealing with this weekend's storm system. But needless to say bitter cold air will be here next week. We could see some below zero temperatures by the middle of next week.
Thursday, January 8, 2009
Baby it's cold outside.
It's going to get colder: It will cold on Sunday with 850 mb falling to -12! But take a look to the north and keep this in mind before looking below.
Bitter cold?
This is the release of the 'polar vortex' or the coldest core of air from the Arctic Circle. The coldest air will still be just a little bit north of our area. That said, it looks like -24 Celsius temperatures at 850 mb. Baby that's really cold
Wednesday, January 7, 2009
Lake Effect Snow Machine
The lake effect snow machine could turn on later this afternoon with a good set up for some places around Fort Wayne to get some accumulating snow. Strong westerly winds will create a pretty good fetch and it will be slippery into this afternoon.