Strange Storm Prediction Center "Interstate" Graphic

[CoreySamson]

So Tulsa is in the crosshairs for severe weather for 4 days in a row this weekend, so naturally I went onto the NWS Storm Prediction Center website to get the latest information. I noticed a checkbox on the map labeled "interstates," and out of curiosity I clicked on it. What I got has to be one of the weirdest interstate maps I have ever seen:



Lots of very strange things on this map:
- Some interstates such as I-22, I-49 in Missouri and Arkansas, I-69 in Indiana, and parts of I-99 are not shown as being part of the interstate system.
- Some states (Ohio, California, Virginia, and North Carolina in particular) have every freeway bypass of small towns on expressway routes marked as an interstate, while other states where this should apply (Texas, etc.) do not have this.
- Some state highway and US highway freeways are included, while others are conspicuously absent (for example, in Oklahoma, OK 375 is obviously there, but the Cherokee Turnpike is not in its entirety).
- Numerous routes that connect into Canada and Mexico that are not even freeways are included (US 57 in Texas, US 201 in Maine, and US 93 in Montana, for example)

I'm very curious what data this map might be pulling from. You can visit the map here:
https://www.spc.noaa.gov/products/exper/day4-8/#

[GaryV]

one of the weirdest interstate maps I have ever seen

In Michigan it looks like it pretty much includes US-highway freeways. I don't think it includes state routes - like M-6 south of Grand Rapids doesn't appear to be there.

And as noted, it's old - witness lack of I-41 in Wisconsin and I-69 in SW Indiana.

[Road Hog]

Looks like "interstate-quality" highways judging by the disconnected segments that may be so. Includes some tollways, but not all because the Dallas North Tollway is not shown. Plus, I-49 north of I-40 and south of I-30 is incomplete.

They have some up-to-date info, but not even close to all of it.

[jlam]

Looks like "interstate-quality" highways judging by the disconnected segments that may be so. Includes some tollways, but not all because the Dallas North Tollway is not shown. Plus, I-49 north of I-40 and south of I-30 is incomplete.

And there's also a smattering of non-freeway expressways, such as US 83 and 85 in North Dakota and SR 90 down in Arizona

[kphoger]

- Numerous routes that connect into Canada and Mexico that are not even freeways are included (US 57 in Texas, US 201 in Maine, and US 93 in Montana, for example)

And there's also a smattering of non-freeway expressways, such as US 83 and 85 in North Dakota and SR 90 down in Arizona

Yet, a couple of other border-bound highways are strangely missing.  Where is US-67 to Presidio?  Where is US-277 to Del Rio?  Where is US-95 to Eastport?  Why do we get the southern bit of US-191 to Mexico but not the northern bit to Canada?

[CoreySamson]

I looked again, and for some reason, the interstate overlay for days 1-3 is different than the one for days 4-8 and is equally as confusing:


What the heck is happening in southern Arizona? Why is the I-49 Bella Vista bypass complete while I-49 north out of Shreveport isn't (even though that section opened first)? Why is nothing happening in the RGV? Where are the new I-69 segments (even those that were present in the other map)?

[Bobby5280]

Yeah those are strange route maps. More than a few of the black route lines get into fictional territory. I do like the line added from Wichita Falls to Fort Worth and hope that becomes a reality in the not too distant future. A Fort Worth to Amarillo Interstate would be even better.

Anyway, I am not liking the weather forecast for the next few days. Late Saturday thru next Wednesday is not looking too good for the Lawton area.

[Bruce]

Seeing as US 97 in Washington is on there, this definitely isn't just freeways on non-Interstate corridors. Also rules out STRAHNET, so maybe it's picking parts of the NHS?

[LilianaUwU]

that's what happens when *gestures broadly*

[bing101]

California has CA-14, CA-99, US-101 and CA-1 included 

[vdeane]

I think it's likely that this is based on "what is useful to show on local TV weather maps", not any objective criteria regarding interstates or other routes.

[The_Ginger]

West Virginia has only Interstates on its map and not any of the ADHSs or NHSs.

[LilianaUwU]

West Virginia has only Interstates on its map and not any of the ADHSs or NHSs.

This says a lot about the Appalachian corridors.

[ClassicHasClass]

California has CA-14, CA-99, US-101 and CA-1 included

Are you sure that's CA 14? That looks more like the I-15/I-215 twin.

No US 395 either, not even south of Reno.

[bing101]

California has CA-14, CA-99, US-101 and CA-1 included

Are you sure that's CA 14? That looks more like the I-15/I-215 twin.

No US 395 either, not even south of Reno.

The map near Newhall Pass looks like CA-14 at first. 

[ElishaGOtis]

Yet it doesn't have I-14 lol

[ZLoth]

In reviewing the map sections for California and Texas, it appears to have the Interstate Routes. However, there are also several US routes listed including US-101 that runs along the California coast as well as CA Route 99. These appear to be Interstate-grade highways.

I take the Interstates as more like reference points to help orient oneself. I really wish they would break down those maps into higher-resolution regions.