All Weather News

Mixed Bag Of Tricks, Spring?

4 Mar 2009, 5:09 pm
Forecast Maximum Temperatures (8 Day)
Forecast Maximum Temperatures (8 Day)
Forecast Precipitation Type (8 Day)
Forecast Precipitation Type (8 Day)
Forecast Minimum Temperature (8 Day)
Forecast Minimum Temperature (8 Day)

The snows certainly have pummeled the Sierras of northern California courtesy of the closed low we discussed on Monday. Precipitation will continue in the form of rains and snows as the remnants of energy continue to propagate inland into the central and northern Rockies.

Accumulations over the next few days will be highest from central Idaho through northwestern Montana, albeit to a greatly reduced extent to that received by northern California, on the order of 4-8″ in some locations.

The southeast will finally be breaking away from the colder temperatures of late and will begin to warm into something a little more seasonable. A look at our Forecast Maximum Temperature Animation (use controls at bottom to stop animation, choose first frame, and advance individually for best results), shows with the first image valid 1pm EST the warmth enjoyed by the southern plains that began with Monday’s discussion. Recall with our forecast maximum and minimum temperature animations, that each frame represents a 6 hour window of time, valid six hours prior to the valid time (timestamp on bottom) , and ending at the valid time. So each frame represents either the maximum or minimum temperature forecast to occur over each time interval.

As we advance to 7pm today, notice the wide breadth of warmth extending once again up into the southern fringes of Nebraska. Recall that on our temperature graphics, we use two “Temperatures of Interest.” The first, the thin blue line represents 72ºF, and the thin red line represents 32ºF. Notice on this frame that the only areas left at or below freezing in CONUS (Continental United States) are specs in the Rockies and Sierras of California, and the northeastern states ranging from Maryland through eastern Pennsylvania and most of New York State through Maine.

The reason this division has occurred is the large area of higher pressure we discussed on Monday has begun to propagate eastward as we will show you shortly.

Now advance the animation through Thursday at 7pm EST and compare the difference. Notice a similar distribution of the 32ºF TOI / freezing line exists in the northeastern United States, while the vast proportion of the southeast, Midwest, and Great Plains states are enjoying considerably milder temperatures than of late. However the poor northern Rockies have some weak cold air advection reducing their temperatures associated with the influx of precipitation we discussed above.

Now go ahead and advance the animation to 7pm Friday EST. Nearly ALL of CONUS from the Great Plains through the south and the northeast are above freezing with the exception of a teenie tiny bit of northern Maine in the northeast, and North Dakota in the northern plains. First time we’ve seen this type of activity for the season! Could spring be trying to show itself! =)

For a long term look go ahead and let the animation fly as the distribution of warm temperatures holds itself for a bit, yet in the future (when, can you tell?) some cold air masses sneak back in to let us know they are still in play. For a better look at those cold night time lows and advancing cold air masses in the future, use our Forecast Minimum Temperature Animation and enjoy yourself!

OK, now for the precipitation we have in our future. We already discussed what’s going on in the Rockies above, but what about what is headed our way? Well let’s open up our Forecast Precipitation Type Animation and see how the forecast of our system has developed. Recall that each frame represents 6 hours of time, prior to and ending at the valid time represented by the timestamp on the bottom. And if precipitation were to fall within that time frame, what type of precipitation might it be, with the addition of course of projected pressure centers and distributions.

On our first time frame valid 1pm EST today, we see the ridge of high pressure we have discussed centered over the mid-atlantic states as it has already begun its trek to the east. The squiggly lines in the Pacific Northwest represent the remnants of the ‘sheared out’ closed low we discussed would occur on Monday. Noticeable is the forecast snow we discussed for the area in higher elevations, and rainfall in lower elevations.

As we advance through Thursday morning at 7am EST, we see a baby low develop just north of Montana, i.e. another Alberta Clipper that is not very impressive, it will slink along to the east dipping slightly south in the northern tier for a bit and drop fairly meager snows, maybe as much as 4″ or so along the northern tier and into Canada. We also see the potential for liquid precipitation running along the Mississippi River, and the potential for mixed running from North Dakota along to Wisconsin. While the possibility for mixed does exist, I do not see the potential for another major ice storm but sleet and freezing rain is definitely possible.

Advance further to 7am on Friday Morning notice the clipper is situated just north of the Great Lakes with the potential for rains extending on the southern flank from the bootheel of Missouri through Massachusetts, the remnants of our high pressure is now situated in the Atlantic off the coast of New Jersey, and here is our little low that we discussed on Monday, at this point centered on the Cherokee Strip.

Advance the animation through 1pm on Saturday, our clipper is now up near Newfoundland, the high is off the east coast of South Carolina, and our new area of lower pressure is forecast to deepen slightly, centered over Dodge City Kansas. From that center of lower pressure, rains are forecast to spread across most of the Midwest, with snows developing from Colorado through the Northern Plains.

By Saturday at 1pm, the low is centered over Chicago with snows extending from northern Iowa through Minnesota, central and northern Wisconsin, and the UP of Michigan, while the balance is forecast to receive rains. Yet by Monday morning the low is over New York State, forecast quickly to head out to sea, while we have another area of lower pressure centered over Dodge City with the potential to dig a little deeper than the previous run. We will get a better view of this system with later model runs. It is kind of nice to have a pair of Dodge City lows though =) Also notice the ridge of high pressure centered over the PNW during this time frame. What will happen next there!

Please be sure to view our Advisory and Radar Centers for the latest updates and developments.

As always stay tuned to your favorite weather outlet, stay informed, and stay safe!



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