The White House has announced that President Trump will sign the Pelosi appropriations bill that includes limited funding for border security, and will simultaneously use a National Security Declaration to shift existing funds to build a structural barrier.
Senate majority leader Mitch McConnell met with the President and announced the plan from the senate floor before the chamber votes on the compromise bill.

.@senatemajldr: "I've just had an opportunity to speak with President Trump…he's prepared to sign the bill. He will also be issuing a national emergency declaration at the same time." pic.twitter.com/iukGKjmoZ8

— CSPAN (@cspan) February 14, 2019

White House Press Secretary Sarah Sanders statement:

Speaker Nancy Pelosi has stated she will review options to file legal challenges to stop the use of a national security declaration to build a border barrier.

https://twitter.com/Breaking911/status/1096147982351769600

Any declaration of a national emergency by Trump is expected to go to court. Public Citizen tells us they're already preparing a lawsuit on behalf of a group of Texas residents, including borderlands owners, and a Texas environmental group https://t.co/dKpI5b3AAc

— Zoe Tillman (@ZoeTillman) February 14, 2019